Page 1
'^;v
; I
T. 0 33A1-12-989-4
VOLTMETER,
ELECTRONiC
MODEL 893A/AC
CONTRACT NO.
F41608-74-D-175€
JOHN FLUKE
mfg. co., inc
Page 2
Page 3
JOHN
FLUKE
MFG.CO,, INC.
RO. Box 43210
Mountiake
Terrace,
Washington
98043
T. 0 33AM2-989-4
VOLTMETER,
ELECTRONIC
MODEL 893A/
AC
CONTRACT NO.
F41608-74-D-1756
Page 4
The
JOHN FLUKE MFC,
CO., INC.* warrants
each instrument
manufactured
by them to
be free from
defects in material
and workmanship.
Their
obligation under this
Warranty is
limited
to
servicing or
adjusting
an instrument
returned to
the factory for
that purpose, and to making
good at the factory
any part or parts
thereof; except
tubes, fuses,
choppers and batteries,
which shali, within
one year after
making delivery
to
the original
purchaser, be
returned
by
the original
purchaser with
transportation
charges
prepaid, and which
upon their examination
shall dis-
close To their
satisfaction to
have been thus defective,
(f the fault
has been caused
by misuse or abnormal
conditions of
operations, repairs
wiii
be
billed
at
a
nominal
cost, in this
case, an estimate will
be submitted before
work is started,
if requested.
If
any fault
develops,
the following
steps should
be taken;
1
.
Notify
the John Fluke
Mfg. Co.,
Inc.,* giving full
details of
the
difficulty,
and include
the Mode!
number, type number,
and
serial
number.
On
receipt of this information,
service data or
shipping instructions
wilt
be forwarded to
you.
2.
On
receipt of
the shipping
instructions, forward
the instrument
prepaid,
and repairs will
be made
at
the factory, if
requested,
an
estimate wiil
be
made before the work
begins,
provided the instrument
is not
covered by the Warranty.
“The foregoing
warranty
is in lieu of all other
warramies,
express or implied,
including
but not limited
to,
any implied
warranty of
merchantability,
fitness or
adequacy for
any particular
purpose or use.
Fluke shall
not
be liable for any special,
incident or
consequential
damages."
SHIPPING
Ail
shipments of John Fluke
Mfg. Co., Inc.*
instruments should
be made via United Parcel
Service or
"Best
Way"*
*
prepaid. The instrument
should be shipped in
the original packing carton;
or if it is not available,
use any suitable
container that is rigid. If
a substitute container is
used,
the instrument should
be wrapped in paper
and surrounded
with at least four
inches of excelsior or similar
shock-absorbing material.
CLAIM FOR
DAMAGE
IN SHIPMENT
The
instrument should
be thoroughly
inspected
immediately upon
receipt. All material
in the
container should
be checked against
the enclosed
packing
list. The
manufacturer will
not be
responsible for
shortages against
the
packing
sheet unless
notified
immediately, If the
instrument
fails
to operate properly,
or is
damaged in any
way. a claim
should be filed with the
carrier.
A
full
report of
the damage should
be obtained
by
the
claim agent,
and this report
should
be forwarded to John
Fluke Mfg. Co., Inc.*
Upon
receipt of this
report, you will
be
advised
of
the
di^osition of
the equipment for
repair or
repiecement. Include
the model
number, type
number, and serial
number
when
referring
to this
instrument
for any reason.
The John Fluke Mfg. Co..
Inc.* will
be happy to
answer all application
questions which
will
enhance your use
of this instrument.
Please ad-
dress
your requests to; JOHN
FLUKE MFG.
CO,,
INC.,
P. O. Sox
7428, SEATTLE,
WASHINGTON
98133*.
*
For European
customers: FLUKE
(Nederland)
B.V.
Ledeboerstraat
27
Tilburg,
Netherlands
**For European
customers. Air Freight prepaid,
FLUKE
TECHNICAL
SERVICE
CENTERS
Fluke
Western
Technical
Center
Mike
Nagy, Service
Manager
2020 North
Lincoln
St.
Burbank,
CA 91504
Tei.
213-849-4641
TWX: 910-497-2086
Fluke Western
Technical
Center
Tom
Marshall, Service
Manager
4805
Mercury
St.
San
Diego,
CA 92111
Tel. 714-565-4455
TWX: 910-337-1273
Fluke
Western
Technical
Center
Attn;
Tom Marshall
2359 De
La Cruz Blvd
Santa Clara,
CA
95050
Tei. 408-244-1505
TWX:
910-338-0121
Fluke S.W.
Technical
Center
Mel
Sueizie,
Service Manager
Unit
4
1980
South
Quebec Street
Denver, CO
80231
Tel. 303-700-1228
Fluke S.E.
Technical Center
Jesse Morse,
Service
Manager
P.O.
Box
6578
940
Nortfi Fern
Creek Avenue
Orlando,
FL 32803
Tel.
305-896-2296
TWX:
810-850-0185
Fluke
Midwestern
Tech Center
Bruce Hunt, Service
Manager
1287 North
Rand Road
Des Plaines,
i L 60016
Tel. 312-298-7470
TWX; 910-233-4978
Fluke
Mideastern
Tech
Center
John Hines,
Service
Manager
11501 Huff
Court
Kensington,
MD
20795
Tel. 301-881-5300
TWX;
710-825-9645
Fluke
N.E.
Technical Center
Dick Zemba,
Service
Manager
109
Massachussetts
Ave.
Lexington,
MA
02173
Tel. 617-861-8620
TWX; 710-826-17
15
Fluke
Midwestern Tech
Center
Robert Wayne,
Service Mgr.
10800 Lyndale Avenue
South
Minneapoiis,
MN 55420
Tei. 612-8844541
TWX: 910-576-3141
Fluke Eastern
Technical
Center
Bernard Ciongoii,
Service Mgr.
101 Berkshire
Ave.
Paterson, NJ
07502
Tei. 201-742-3215
TWX: 710-988-5945
Fluke
Eastern Technical
Center
Frank
Forte,
Service Manager
4515
Culver
Road
Rochester, NY
14622
Tel - 716-342-6940
TWX; 510-253-6145
Fluke
S.E. Technical
Center
Dwain
Cox, Sewice
Manager
P.O.Box
9619
1310 Beaman Place
Greensboro,
NC 27408
Tel. 919-273-1918
I WX: 5
10-925-1
173
John Fluke Mfg.
Co.,
Inc.
Bill
Fetrow, Tech, Services
Spvr.
7001
-
220th S.W.
Mountlake Terrace,
WA
98043
Tel.
206-774-2238
TWX; 910449-2850
Fluke
Canadian Techtiical Center
Tony
Unser, Service Manager
640
nth Ave. S.W.
Calgary,
Alberta
Tel. 403-261-0780
TWX: 610-821-2233
Fluke
Canadian Technical Center
Herb
Duval, Service Manager
6427
Northam Drive
Mississauga,
Ontario
Tel.
416-678-1500
TWX: 610492-2119
Rev.
5/75
Page 5
ADDENDUM
Model
893A/AC
Electronic
Voltmeter
T.O. 33A1
-
12-989-4
'Diis Instruction Manual for the Model 893A AC/DC
Differential Voltmeter has been
modified to meet the requirements of Air Force Contract No. F41608-74-D-1756.
All information contained in this manual, modified as required, is applicable to
instru-
ments provided on this contract.
Page 6
Page 7
JOHN
FLUKE
MFG.COJNC.
RO,
Box 43210
Mountiake
Terrace,
Washington 98043
Rev. 1
8/30/71
Rev. 2
9/22/71
Rev.
3 6/16/72
Rev.
4 7/23/73
Rev. 5
2/10/75
294272
MAY,
1969
Page 8
The
JOHN FLUKE MFG.
CO., INC.* warrants
each instrument
manufactured by them to
be free from
defects in
material and workmanship.
Their obligation
under this Warranty
is limited
to servicing or adjusting
an instrument
returned to
the
factory
for
that purpose,
and to making
good at the factory
any
part
or parts thereof;
except tubes, fuses,
choppers and batteries,
which shall, within
one
year after making
delivery to
the original
purchaser,
be
returned
by the original
purchaser with transportation
charges prepaid,
and which
upon their
examination shall
dis-
close
to their satisfaction
to have been thus
defective, if
the
fault
has been caused by misuse or
abnormal
conditions
of operations,
repairs wifi
be billed at
a
nominal cost. In
this case, an estimate
wit! be submitted
before work is started, if
requested.
If any fault
develops, the following
steps should
be
taken:
1. Notify
the John Fluke Mfg.
Co., Inc.,* giving
full details of
the
difficulty,
and include
the Model
number,
type
number,
and serial
number.
On receipt
of this information,
service data or
shipping instructions
will
be
forwarded
to you.
2. On receipt
of the shipping
instructions, forward
the instrument
prepaid,
and repairs will
be made
at the factory. If
requested, an
estimate will
be made before
the work begins,
provided the
instrument is not
covered
by
the Warranty.
"The foregoing warranty
is in lieu of all other
warranties,
express or implied,
including
but not limited
to,
any implied warranty of
merchantability,
fitness or
adequacy
for
any
particular
purpose or use.
Fluke shall
not be liable for any
special, incident
or consequential
damages."
SHIPPING
All
shipments of John Fluke Mfg. Co.,
Inc.* instruments should
be made via United Parcel Service
or
"Best Way"** prepaid. The
instrument
should be shipped in the original packing
carton; or if it is not
available, use any suitable
container that is rigid. If
a substitute
container is
used,
the instrument should be wrapped
in paper and surrounded
with at least four inches of
excelsior or similar
shock-absorbing
material.
CLAIM FOR
DAMAGE IN
SHIPMENT
The
instrument should be
thoroughly
inspected immediately
upon receipt. All material
in
the container should
be checked
against the enclosed
packing
list.
The manufacturer will
not be responsible for
shortages against
the packing sheet
unless notified
immediately.
If the
instrument
fails
to operate properly,
or is damaged
in any way.
a claim should ba filed
with the carrier.
A full report
of the damage
should
be obtained
by the claim agent,
and this report
should be forwarded
to John Fluke Mfg.
Co.,
Inc.'
Upon
receipt of
this report, you
will be advised
of the
disposition
of the equipment for repair or
replacement,
include the model
number,
type number, and serial
number
when referring
to this
instrument
for any reason.
The John Fluke Mfg. Co.,
Inc.* will
be happy to answer all
application
questions which will
enhance your
use of this
instrument.
Please ad-
dress
your requests to: JOHN
FLUKE MFG.
CO.. INC,, P,
O. Box
7428,
SEATTLE.
WASHINGTON 98133*.
*
For European customers:
FLUKE
(Nederland) B.V.
Ledeboerstraat
27
Tilburg,
Netherlands
**For European
customers, Air Freight
prepaid.
Fluke
Western Technical
Center
Mike Nagy.
Service
Manager
2020 North
Lincoln
St.
Burbank,
CA
91504
Tel. 213-849-464!
TWX:
910-497-2086
Fluke
Western
Technical
Center
Tom
Marshall,
Service
Manager
4805
Mercury
St.
San Diego,
CA 9211 1
Tel. 714-565-4455
TWX: 910-337-1273
Fluke
Western
Technical
Center
Attn;
Tom Marshall
2359 De
La
Cruz
Bivd
Santa Clara,
CA 95050
Tel. 408-244-1505
TWX; 910-338-0121
Fluke
S.W.
Technical Center
Mel
Suelzle, Service
Manager
Unit
4
1980 South
Quebec Street
Denver,
CO
80231
Tel-303-750-1228
Fluke
S.E. Technical Center
Jesse
Morse, Service Manager
P.O.Box
6578
940 North Fern
Creek
Avenue
Orlando,
FL 32803
Tel. 305-896-2296
TWX:
810-850-0185
Fluke
Midwestern
Tech Center
Bruce
Hunt, Service
Manager
1287 North
Rand Road
Des
Plaines,
!L 60016
Tel
-
312-298-7470
TWX:
9I0-233-497S
Fluke
Mideastern
Tech Center
John Hines,
Service Manager
1
1501 Huff Court
Kensington,
MD 20795
Tel.
301-881-5300
TWX:
710-825-9645
Fluke
N.E. Technical Center
Dick
Zemba, Service
Manager
109
Massachussetts
Ave.
Lexington, MA
02173
Tel. 617-861-8620
TWX: 710-826-1715
Fluke
Midwestern Tech
Center
Robert Wayne, Service
Mgr.
10800 Lyndale Avenue
South
Minneapolis, MN
55420
Tel.
612-884-4541
TWX: 910-576-3141
Fluke Eastern
Technical Center
Bernard Ciongoli,
Service Mgr.
101
Berkshire Ave.
Paterson,
NJ 07502
Tei. 201-742-3215
TWX; 710-988-5945
Fluke Eastern
Technical Center
Frank Forte,
Service Manager
4515 Culver
Road
Rochester,
NY 14622
Tei. 716-342-6940
TWX: 510-253-6145
Fluke
S.E. Technical Center
Dwain Cox,
Service Manager
P.O.Box
9619
1310 Beaman Place
Greensboro,
NC 27408
Tel.
919-273-1918
TWX:
510-925-1
173
John Fluke Mfg.
Co.. Inc.
Bill Fetrow,
Tech, Services Spvr.
7001
-
220th S.W.
Mountiake
Terrace, WA 98043
Tel.
206-774-2238
TWX; 910-449-2850
Fluke
Canadian Technical
Center
Tony Unser,
Service Manager
640
11th
Ave.
S.W.
Calgary, Alberta
Tel.
403-261-0780
TWX; 610-821-2233
Fluke Canadian
Technical Center
Herb
Duvat, Service
Manager
6427
Northam Drive
Mississauga,
Ontario
Tel. 416-678-1500
TWX:
610492-21
19
Rev. 5/75
Page 9
Section Title
Page
I INTRODUCTION AND SPECIFICATIONS 1-1
1-1. Introduction 1-1
1-5.
Electrical Specifications 1-1
1-6.
Differential Voltmeter 1-1
1-
7. Conventional
Voltmeter (TVM)
1-2
1-8.
General Specifications 1-2
1-9,
Environmental Specifications
1-2
1-
10. Mechanical Specifications
1-3
n OPERATING INSTRUCTIONS 2-1
2-
1.
introduction
2-1
2-4.
Operating Features
2-1
2-6.
C^eration from
115/230
volt
AC
Power Lines 2-1
2-9.
Preliminary Operating Procedures 2-1
2-11.
C^erational Test
2-1
2-15,
Operating Notes 2-4
2-
16. Ground Loop Currents 2-4
2-18. Common
Mode Voltages
2-4
2-20.
Use of Shorting Link
2-4
2-22.
DC Differential Off-Null iiput Resistance .
. .
2-4
2-24. TVM Mode Operation 2-5
2-26. Differential
Mode Operation
2-5
2-28. Optional Recorder
Output Operation
2-6
2-
30.
Applications
2-31.
Introduction
2-6
2-33.
Measurement of Voltage Excursions About
a Nominal Value
2-6
2-35.
Measurement of Extremely High Resistances
.
2-6
2-37.
Operation as
a
Null Detector
2-7
2-
39. Measurement of DBM
2-7
m
THEORY
OF
OPERATION 3-1
3-
1. fiitroduction
3-1
3-3.
Block Diagram Analysis 3-1
3-
4. fiitroduction 3-1
3-6.
Conventional
TVM
Mode 3-1
3-9.
Differential Null Mode 3-1
3-12.
Optional Recorder Output 3-2
3-14. Circuit Analysis 3-2
3-15.
Introduction 3-2
3-17. Power Supply/Battery Charger 3-2
3-20. The
Reference Supply
3-3
3-28.
Kelvin- Varley Divider
3-4
3-33.
AC Converter 3-5
3-38.
NullDetector 3-6
3-43.
DC Input Divider 3-7
3-46.
Optional
Recorder
Output 3-7
(Continued
pg.
ii)
89.“^
A
Page 10
(Table
of Contents,
continued)
Section
Title
Page
IV
MAmTENANCE
4_1
4-1.
Introduction
4_1
4-5.
Service
Morination
4_i
4-8.
Disassembly
Eistructions
4-2
4-9.
The Model
893A Disassembly
Instructions
. .
4-2
4-11.
The Model
893AR
Disassembly
Instructions
.
.
4-3
4-13.
General Maintenance
4_3
4-14.
Periodic
Cleaning
4-3
4-17,
Fuse
Replacement
4-3
4-19.
Battery
Replacement
4-3
4-21.
Precalibration
and
Troubieshootii^
4-7
4-22.
Introduction
4-7
4-25.
Reference Amplifier/Reference
Inverter
Checks
4-7
4-28.
Null
Detector/Divider
Checks
4-9
4-31.
Kelvin-
Varley Divider Checks
4-10
4-34.
Recorder
Output Option
Checks
4-10
4-37.
AC Converter
Checks
4-11
4-
40.
Calibration Procedures
4-12
4-41.
Introduction
4-12
4-45.
Meter
Mechanical Zero
Adjust
4-12
4-47.
Zener Reference
Supply Calibration
4-14
4-49.
Null Detector
Calibration
4-14
4-51.
Kelvin-
Varley Divider Calibration
4-15
4-53.
DC
Voltage
Range Calibration
4-15
4-55.
AC Converter
Calibration
.
4-16
V LIST OF REPLACEABLE
PARTS
5-1
5-
1,
Eitroduction
5-1
5-4.
Column
Description
5-1
5-5.
How
to Obtain Parts
5-2
5-8.
List
of Abbreviations
5-2
5-9.
Serial
Number Effectivity
5-37
APPENDIX
A
JOHN
FLUKE MFG. CO.
WARRANTY
LIST OF SALES
REPRESENTATIVES
LIST
OF FACTORY
AUTHORIZED
SERVICE CENTERS
SCHEMATIC DIAGRAM
Rev. 4
7/23/73
ii
893A
Page 11
Ut7iiA.
IONS
Figure
Title
Page
Frontispiece
Models 893A
and 893AR AC-DC Differential
Voltmeter
vi
1-1.
Model
893A Outline
Drawing.
1-3
1-
2.
Model 893AR Outline Drawing 1-3
2-
1.
The Model 893A Controls, Terminals,
and
Indicators
{Sheet
1
of
2). . .
2-2
2-1.
The
Model
893A
Controls, Terminals, and Indicators (Sheet
2 of
2).
.
.
2-3
2-2. The Model 893AR Controls, Terminals,
and
Indicators (Sheet
1 of
2) . .
2-3
2-2. The Model 893AR Controls, Terminals, and Indicators (Sheet
2
of
2) . .
2-4
2-3.
Readout Dials
Versus Null Sens Checks
2-4
2-4.
Off-Null DC
Input
Resistances
2-5
2-5. Bridge Detector-Floating Supply
2-7
2-6. Bridge Detector-Floating Null Detector
2-7
2-
7.
1
Volt Range DBM Conversion Table
2-7
3-
1.
Model
893A/AR
Block
Diagram 3-2
3-2.
Reference
Amplifier/Reference Inverter
-
Simplified
3-3
3-3. AC Converter Block Diagram
3-5
3-
4.
Null Detector Block Diagram 3-6
4-
1.
Required Test Equipment
4-2
4-2. Adjustment and Test Point Locations (Sheet
1
of
4)
4-4
4-2.
Adjustment and Test Point Locations (Sheet
2
of
4)
4-5
4-2. Adjustment and Test Point Locations (Sheet 3 of
4)
4-6
4-2. Adjustment and
Test
Point
Locations
(Sheet
4 of
4). .
4-7
4-3. Reference Amplifier/Reference Inverter Checks
-
Equipment
Connections
4-8
4-4. Reference Amplifier/Reference
Eiverter Waveforms
4-9
(Continued
pg.
iv)
iii
aao A
Page 12
(List of aiustrations,
continued)
r-v
i
i
Figure
Title
Page
4-5.
Input DC
Voltage Versus
Range
-
Checks
4-10
4-6.
Null Detector Waveforms
4-10
4-7.
Input Voltages
Versus Readout Settings
-
Checks
4-10
4-8.
Recorder Output
Waveforms
4-11
4-9.
AC Converter
Range Checks
4-12
4-10.
AC Converter
Waveforms
4-12
4-11.
Summary of Calibration
Adjustments (Sheet
1 of
2)
4-13
4-11.
Summary of Calibration
Adjustments
(Sheet 2 of
2)
4-14
4-12.
TVM Range
Checks
4-15
4-13.
Jumper Wire Location
4-15
4-14.
Jumper Wire Selection
4-16
4-15.
Vernier
Dial
Set Screw Location
4-16
4-16.
100 Volt Range Checks
4-17
4-17.
10 Volt Range Checks
4-17
4-18.
1 Volt Range
Checks
4-17
4-19.
1 Volt Range
(0,
1
Scale)
Checks
4-17
4-
20. 1 Volt Range
(0.
001 Scale) Checks
4-17
5-
1.
893A AC/DC
Differential Voltmeter (Sheet
1 of
2)
5-4
5-1.
893A AC/DC Differential Voltmeter (Sheet
2 of
2)
5-5
5-2.
Front Panel Assembly
(893A) 5-6
5-3.
Reference Amplifier P/C Assembly
5-8
5-4.
Reference Inverter P/C Assembly
5-12
5-5.
Null Detector
P/C Assembly
5-14
(Continued
pg.
v)
iv
893A
Page 13
(List of
Illustrations,
contiiiued)
Figure
Title
Page
5-6.
Kelviii-Varley P/C Assembly 5-18
5-7.
AC Converter P/C
Assembly
5-25
5-8.
Rear Panel Assembly (893A) 5-26
5-9.
893AR AC/DC Differential
Voltmeter (Sheet 1 of
2)
5-28
5-9.
893AR AC/DC Differential
Voltmeter
(Sheet
2 of
2)
5-29
5-10. Front Panel Assembly (893AR)
5-30
5-11.
Rear Panel Assembly (893AR) 5-31
5-12.
Battery
and
Recorder
Output
Options
5-33
5-13, Battei'y Option
(-01)
Installation (Sheet 1
of
2)
5-35
5-13.
Battery Option
(-01)
Installation
(Sheet 1 of
?) 5-35
V
893A
Page 14
893A
Page 15
1-1.
INTRODUCTION
1-2.
The Fluke Model 893A and AR AC-DC
Differ-
ential Voltmeters provide conventional or
differential
measurements
of ac voltages from one millivolt
to 1100
volts ac and dc voltages from
10
microvolts
to 1100 volts
dc. Conventional (TVM)
measurements are made with
an accuracy of
±3%
of the
selected range to initially
determine
the magnitude of the measured
voltage. The
differential
(NULL) mode is then used with an
improved
accuracy
of up to
250%
over that
of
the conventional
mode to determine the
exact value of the measured volt-
age. One linear meter-scale
greatly simplifies
all
measurements made with the instrument. Whenever the
instrument
is operated on the differential mode,
an
in-
line
digital readout representing the
magnitude of
the
measured voltage is available
from
the
front panel Read-
out dials.
1-3.
Two versions
of the instrument are available and
are identified
as the Model 893A or Model 893AR.
The
Model 893A is a portable unit, half-rack in width, with
a tilt-down carrying handle. This handle detents into
the instrument's feet to
serve as a tilt-bale during
bench-top use of the instrument. The
Model 893AR is
also a portable unit, but is
of proper
width
for instal-
lation in a standard electronic
equipment rack. Car-
rying of this instrument
is provided by two front panel
handles,
A
tilt-down
bale located on the bottom of the
instrument
facilitates bench-top use of the instrument,
1-4.
A rechargeable battery
and recorder output op-
tions are also available
for
either
version of
the
instru-
ment. These
options can be installed at the factory,
upon request, or in the field. Option Kit
893A-7001
comprises the rechargeable
battery pack and, when in-
stalled in the instrument, is identified
as
the
-01
option
on the rear panel decal. Option Kit
893A-7002 com-
prises the recorder
output and, when, installed
in the
instrument,
is identified as the
-02
option on the rear
panel decal.
1-5.
ELECTRICAL
SPECIFICATIONS
1-6.
DIFFERENTIAL
VOLTMETER
DC ACCURACY
,
£3
'z-
y
±{0. 01%
of input +0.
001%
of range +10
uv) from
0 to 1100
volts
dc at 23®C ±2“C
with up to
80%
relative
humidity.
±(0.
02%
of input
+0.
001%
of range +10
uv) from
0 to 1100
volts dc at
10“C to
40“C (50*F to
104“F) with up
to
70%
relative humidity.
AC ACCURACY
O> tf-
At
23°C ±2'’C with less
than
70%
relative
humidity:
50 Hz to lO kHz
0.
001 to 500 volts
ac
±(0.
05%
of input +25
uv)
500 to 1100 volts
ac
±0.
1%
of input
At 10°C to
40°C with less than
5
Hz to 10 Hz
0. 001 to 1100
volts ac
10 Hz to 20 Hz
0.
001to1100 volts
ac
20 Hz to 50 Hz
0. 001 to
1100 volts ac
50
Hz to 20 kHz
0. 001 to 110 volts
ac
110 to 1100
volts ac
20
kHz to 50 kHz
0.001 to
110 volts
70% relative humidity:
±{l% of input
+250 uv)
±(0.
5%
of
input +100
uv)
±(0.
15%
of input
+25 uv)
±{0.
1%
of input +25
uv)
±0.
15%
of input
±(0.
15%
of input
+25 uv)
1-1
8 9,3A
Page 16
50 kHz to 100 kHz
0. 1 to 110 volts ac ±0.
5%
of input
1-8.
GENERAL
SPECIFICATIONS
INPUT AND NULL VOLTAGE RANGES
ELECTRICAL
SPECIFICATIONS
Completely
solid-state
INPUT RANGES
1
10
100
1000
DC
NULL
RANGES
0 . 001,0 . 01
,
0 . 1
0 . 001
,
0 . 01
,
0
.
1
,
1.0
0 . 01,0
. 1
,
1 . 0
,
10
0
.
1
,
1
. 0
,
10
,
100
INPUT RANGES
1
10
100
1000
AC NULL RANGES
0.001,
0.
01^
0.
0.01,
0.1,
1.0
0.
i,
1.0,
10
1.0, 10,
100
DC INPUT RESISTANCE
Infinite at null
from 0 to 1100 volts dc.
AC INPUT IMPEDANCE
One megohm shunted by
less
than
20
pf on all ranges.
OVERRANGE
10%
overrange
capability
on
each
range.
METER RESOLUTION
10 microvolts maximum resolution.
1
ppm of range for dc ranges above one volt.
10
ppm
on the one volt dc range and all ac ranges.
READOUT
DIAL RESOLUTION
10
microvolts
maximum
(10
ppm of range).
1-7. CONVENTIONAL
VOLTMETER (TVM)
DC VOLTMETER ACCURACY
±3%
of range.
INPUT RESISTANCE
OF NULL
DETECTOR
10 megohms on the 0.
01 and 0, 001 volt ranges and
100
megohms on
all other ranges.
REFERENCE
ELEMENT
Temperature compensated
zener diodes.
REGULATION
OF REFERENCE
SUPPLY
0.
0005%
for
a
10%
line change.
REFERENCE
VOLTAGE STABILITY
(Peak-to-Peak)
10
ppm per hour
20
ppm per day
40
ppm per month
90
ppm per year
KELVIN-VARLEY DIVIDER ACCURACY
±0.
005%
of readout dial setting
above l/lO of
full-scale.
RECORDER OUTPUT
Available
as
the
-02
option,
adjustable
from
0 to ±0.2
volts for an
end-scale meter deflection. Low
side
grounded and loading
does
not
effect deflection accuracy.
POLARITY
Reversible with
front panel control.
WARM-UP TIME
Less than one minute.
DC COMMON MODE REJECTION
120
db
(1
uv/volt of common
mode voltage) for
maximum
of ±500 volts.
AC VOLTMETER ACCURACY
5
Hz
to 20
kHz
O.OOl to 1100
volts
ac
±3%
of
input
20 kHz to 100 kHz
0, 001 to 110 volt ac
±3%
of input
DC INPUT RESISTANCE
RANGE INPUT RESISTANCE
-
Megohms
1000 100
100 100
10
100
1 100
0 . 1
-
0
-
0.
100
*
0 . 01-0
-
0
.
01
10
*
0
.
001
-
0-0
.
001
10
These ranges obtained using
null ranges with Readout
dials
set to zero.
AC INPUT IMPEDANCE
One megohm shunted by
less
than
20
pf on all ranges.
OVERRANGE
10%
overrange capability
on
each range.
1-2
AC COMMON
MODE REJECTION
Up to 100 volt peak-to-peak,
50 to 500
Hz signal, pro-
duces no
measurable instrument error
for dc measure-
ments.
INPUT POWER
115/230 volts ac, 50 to 500
Hz, at approximately
four
watts for line operation
and approximately
eight watts
when recharging
batteries on the
-01
option equipped
instruments.
Minimum of eight hours
operation on fully
charged batteries
of the
-01
option
equipped instru-
ments.
1-9.
ENVIRONMENTAL
SPECIFICATIONS
OPERATING TEMPERATURE
RANGE
Within dc accuracy
specifications
from
10°
C to
40°
C
(50°F to
104°F), derated at
15
ppm/°C outside these
limits
to 0°C and
50°C (32°F and
122°F).
Within ac accuracy
specifications from
10°
C to
40°
C
(50°F
to
104°
F), derated at
40
ppm/°C outside these
limits to 0°C and
50°C (32°F and 122°F).
HUMIDITY
Within
all specifications up to
80%
relative
humidity be-
low
25°
C.
6/16/72
893A
Page 17
Within
all
specifications up to
70%
relative humidity
a-
bove 25°C.
STORAGE TEMPERATURE RANGE
Model 893A/AR -40°C to 70°C {-40°F
to
158°F)
Model 893A/AR-01 -40' C to
60°
C
(-40°
F
to
140°
F}
SHOCK AND VIBRATION
Meets MIL-T-945A.
1-10.
MECHANICAL
SPECIFICATIONS
SIZE
Model 893A
See Figure
1-1
Model 893AR
See Figure
1-2
WEIGHT
Model 893A
Approximately
12
pounds
Model 893AR
Approximately
12
pounds
Option -01 (Option kit 893A-7001)
Approximately
2
pounds
Option
-02
(Option kit 893-7002)
Approximately
0.
3
pounds
OPTION KIT 893A-7001
Provides rechargeable battery pack for
installation in
either version instrument.
OPTION KIT 893A-7002
Provides a recorder output for installation in
either ver-
sion instrument.
8
-
30-71
1-3
893A
Page 18
Page 19
2-1.
INTRODUCTION
2-2.
This section
of
the
manual contains information
necessary
for you to effectively operate
your Model
893
AC/DC Differential
Voltmeter. It is recommended
that
you thoroughly
read and understand this
section of the
manual
before attempting to operate
your instrument.
POWER
RANGE
NULLS SENS
MODE
Readout dials
ON/LINE OPR
1000
TVM
+
000
.^
2-3.
Should
any
difficulties
be encountered during
the operation
of your
instrument,
please feel
free
to
contact your nearest John
Flulce Sales Representative
or write directly to the
John Fluke Mfg. Co.
,
Inc.
P.O.
Box
43210,
Mountlake Terrace, Wn.
98043,
with
a
statement
of your problem.
A
complete
list of Sales
Representatives
is contained
at the
rear of tMs manual.
2-4.
OPERATING FEATURES
2-5.
All of the controls,
terminals, and indicators
for
the
Model 893A and the
Model 893AR are illustrated
and described in Figure
2-1
and
Figure 2-2,
2-6.
OPERATION FROM 115/230
VOLT
AC POWER
LINES
2-7.
The Model
893 may be operated from either
a
115 or 230
volt ac power line. The input
power trans-
former
primary is composed
of
two
windings which,
when connected
in parallel, allows the instrument
to be
operated from
a
115 volt
ac power line or, when the
windings are connected
in series,
allows
the
instru-
ment to
be
operated
from
a 230
volt
ac power line.
2-8.
A rear panel
115/230 slide
switch
(S5) provides
the necessary
power transformer
primary winding con-
nections
when placed to the
desired 115 or 230 volt
position.
2-9.
PRELIMINARY
OPERATING
PROCEDURES
2-10.
Connect the Model
893
power cord to available
line power. If your instrument
does
not contain the
-01
option,
perform only
step
a. If your instrument
contains
the -01
option,
perform steps a
through c.
WARNING!
The
instrument case
is
connected
to
the
round
pin of
the three-prong
connector
located
on
the
power cord. Whenever the
instrument is operated
from
ac
line power,
ensure that
this round pin is connected to
a high quality earth
ground.
a.
Place the instrument controls
as
follows
and allow
at
least one minute of circuit stabilization
before
attempting any measurements.
2/10/75
The
Readout
dial labeled OO in the
preceding
step, represents the extreme
right-hand
vernier
dial.
b.
Place
the -01 option
equipped instrument POWER
switch to BAT CHK, observing that the meter needle
deflects to the left
of
the
-,
2 volt increment.
If
the
batteries
are
adequately charged,
the
instru-
ment
can
be operated on
battery
power
by placing
the POWER switch to either BAT OPR or BAT
OPR/LINE ISOL. To completely isolate your in-
strument
from
the
line power ground,
disconnect
the power cord
from line power.
c. If
the BAT CHK test results in
a deflection of less
than
.
2 volts on the meter, place the
POWER switch
to
BAT
CHG
and operate the
instrument from line
power until
the
batteries are adequately charged.
All measuremaits can be performed during recharg-
ing of the batteries. Should the
batteries
fail the
BAT CHK test after 16 hours
of recharging,
replace-
ment
of
the
batteries may be necessary. Refer to
Section
IV,
paragraph
4-19
and
4-20
for battery re-
placement instructions.
Battery manufacturers recommend
that nickel-
cadmium batteries should
not
be stored for
extended periods of
time without
recharging
at
least
every
90
days. Storage
temperatures
below
25‘^C are recommended.
2-11.
OPERATIONAL
TEST
2-12. The
following information
is
provided
for
the
operator to initially
verify instrument operation. These
tests
will only check relative instrument operation
and
are not intended
as
instrument
performance checks.
Should you wish to
check
the
accuracy of the instru-
ment against the
specifications contained in
Section
I,
refer to the
Performance Checks contained in
Section
rv of this manual.
2-13.
To
determine relative instrument operation,
perform the operations
described in the Preliminary
Operating
Procedures (paragraphs
2-9
and 2-10) and
proceed as follows:
a.
Place the
RANGE control to
1.
2-1
A
Page 20
XD
©
METER Indicates the magnitude and poiarlt/ of the measured voltage
on the TVM mode. On
the
differential mode, the meter
or
-
deflection Indicates that the measured
voltage
is
above
or
below
the
readout dial
indication.
©
POWER
SWITCH Controls application of input power to the instrument. When
placed
to
the
LINE
OPR
position,
the instrument is operated from the
available
line power. On
Instruments
equipped with the 01 Option, additional switch positions
of
BAT CHK, BAT OPR-LINE
ISOL, and LINE
OPR-BAT
CHG
are
Included,
When
placed to
the BAT CHK
position
,
the front pane!
meter indicates the charge condition of
the
battery pack, A
meter
indication
of at
least
-.2
is required
before the
instrument
is to be operated from the
battery power. When placed to the BAT OPR-LINE ISOL position, the Insrument is
operated from battery power and the power transformer is completely disconnected from
line power.
However, to completely isolate
the
instniment
circuitry from power line
ground, the line power cord must be disconnected. When
placed to the LINE
OPR-BAT
CHG
position,
the
instrument
Is
operated from
line power and the battery pack Is being
charged
©
NULL SENS SWITCH Provides
selection of the TVM
mode
of operation and selection of the various
full-
scale
null detector sensitivity ranges when the instrument
is operated on the differential mode.
©
RANGE SWITCH Allows selection of the desired input
voltage range of
the instrument, while at
the same
time
simultaneously positioning the readout dial decimal
point
and
selecting the avail-
able
ranges of
the
NULL
SENS switch.
©
READOUT DIALS
Provide
an in-line
digital readout of the measured voltage when
the instrument
is
operated on the
differential mode.
©
MODE SWITCH Selects the AC or DC mode of operation. This
switch
should
be ploced to
the +
position
on
the DC TVM mode. The
±
positions
provide
a means of reversing
the
internal refer-
ence supply voltage on the dc
differential
mode.
2-2
Figure 2-1.
THE
MODEL
893A CONTROLS, TERMINALS,
AND
INDICATORS
(Sheet 1
of
2)
893A
Page 21
©
GROUND TERMINAL
Provides for connection
to
earth ground, provided of
course
that the line cord is
connect-
ed to available line
power.
©
INPUT TERMINALS Provide connection to the measured voltage
source.
©
MECHANICAL
ZERO CONTROL
Allows mechanical
zeroing of the meter.
Figure
2-1
.
THE MODEL 893A CONTROLS, TERMINALS, AND INDICATORS
(Sheer 2 of
2)
MODE SWITCH
Selects the AC or DC
mode of
operation. This switch
should be placed to the
*
position
on
the DC TVM
mode.
The
± positions provide
a meons of reversing the internal refer-
ence supply
voltage on
the dc
differential mode.
READOUT
DIALS Provide on
in-line digital readout of the
measured voltage when the
Instrument is
operated on the
differential mode.
POWER
SWITCH
Controls application of input power to the
insturment. When placed to
the
LINE OPR
position, the instrument Is operoted
from
the
available line power. On instruments equip-
ped with
the 01 Option, additional switch positions
of BAT
CHK,
BAT OPR-LINE ISOL,
and LINE OPR-BAT CHG
are Included, When
placed
to
the BAT
CHK
position, the front
panel
meter Indicates the charge condition of the
battery pack. A meter indication of at
least
-.2 is required before the instrument is to be
operated from the battery power.
When
placed
to
the BAT OPR-LINE iSOL position,
the instrument is
operated from battery
power and the
power transformer Is completely
disconnected from line power.
However,
to completely isolate
the instrument circuitry from
power line ground, the line power
cord
must be
disconnected. When placed to the LINE OPR-BAT
CHG position, the instrument
is operated from the
line power and the battery pack is
being charged.
NULL
SENS
SWITCH Provides selection
of the TVM mode of operation
and selection of
the
various full-scale
null
detector sensitivity ranges when the
iristrument is operated
on
the differential mode.
RANGE SWITCH Allows selection
of the
desired
input
voltage range
of
the instrument, while at the same
time simultaneously
positioning the
readout dial decimal point
and
selecting the avail-
able ranges of the
NULL SENS switch.
MECHANICAL
ZERO CONTROL
Allows
mechanical zeroing of the meter.
GROUND
TERMINAL Provides for
connection to earth ground,
provided
of
course that
the line cord is connect-
ed to available
line power.
INPUT TERMINALS Provide connection to
the measured
voltage source.
Figure
2-2.
THE MODEL 893AR CONTROLS, TERMINALS,
AND INDICATORS
(Sheet 1 of
2}
SQ'JA
Page 22
METER Indicated the
magnitude and polarity of
the
measured
voltage on the TVM
mode. On the
differential mode/ the meter+or-deflection indicates
that the
measured
voltage is above
or
below the readout dial indication.
Figure
2-2.
THE MODEL 893AR CONTROLS, TERMINALS, AND
INDICATORS (Sheet
2 of
2)
b.
Touch the HI INPUT terminal and the chassis of the
instrument with your hand, oteerving that the
meter
pointer deflects to the right or left.
c. Place the MODE switch to the -DC position and re-
peat step
b.
The meter pointer should deflect in the
opposite direction
by
approximately the
same a-
mount observed in step b. Place the MODE switch
to the +DC
position upon completion
of
this step.
d.
Remove the shorting strap from between the LO and
groxmd
INPUT terminals
and
connect the
strap be-
tween the
HI
and LO
INPUT terminals.
e.
Perform the Readout dials versus NULL SENS
checks of
Figure
2-3,
observing that the meter
pointer indicates
-1
for each particular check.
READOUT DIALS
NULL
SENS
OOOX
.001
. 00100 .001
.01000 .01
.
10000
.1
Figure
2-3. READOUT
DIALS VERSUS
NULL
SENS CHECKS
f.
Place
the Readout
dials and NULL SENS
switches
to their respective .
10000
and
.
1
positions,
observ-
ing that the
meter
pointer
indicates
-1.
g.
Retaining the
control
positions of step f,
place the
RANGE
switch to
each available
position,
observing
that the meter
pointer
indicates
-1
in all
positions
of the RANGE
switch.
h. Place
the Model 893
controls
to the following
posi-
tions:
POWER
ON/LINE
OPR
RANGE
1
NULL SENS
.001
MODE
AC
Readout dials
000. 00
i.
Touch the
HI
INPUT terminal of
the Model 893,
observing
that a deflection
is obtained on
the meter.
2-14.
If
the results of the
C^erational Test agree
with
information given,
it can
be
assumed
that the instru-
ment is
operating properly
and measurements of ac
and
dc
voltages can now
be performed.
2-15.
OPERATING NOTES
2-16.
GROUND
LOOP CURRENTS
2-17.
A
potential
difference often exists
between dif-
ferent points of
power system grounds.
Consequently,
2-4
current may flow from one power system ground through
the voltmeter and the voltage source being measured to
another power system ground during the measurement
process. These ground loop currents should be avoided
as
they generate voltages that degrade measurement ac-
curacy. To prevent these
ground
loop currents, when
the system being measured is groimded, remove
the
shorting strap between the LO INPUT terminal and the
ground terminal of the Model 893 or, if
your
instrument
is
equipped
with the
-01
Option,
operate the
instrument
from
battery
power
with
the line cord
disconnected from
line power.
2-18.
COMMON MODE VOLTAGES
2-19.
Great care has been
taken in the design
and
con-
struction
of
this
instrument to isolate the circuitry from
chassis ground to reduce common mode measurement
errors caused partly
by
leakage currents. Accurate
dc measurements can be made in the presence
of
com-
mon mode voltages up to 500 volts
dcorac
voltages up
to 100 volts peak-to-peak at 50 to 500 Hz. If the com-
mon mode voltage is greater than 50
volts,
the meas-
urement should
be made several
minutes after the
equipment connections for best accuracy due to the time
required to charge the stray capacitance through the
extremely high
leakage
resistance to ground.
2-20. USE OF SHORTING LINK
2-21.
The INPUT
ground terminal is directly connected
to
the chassis of the instrument
to
provide a
convenient
connection to
earth ground whenever the line cord
is
connected
to
line
power.
Whenever measurements of
voltages
having
a
reference other than ground,
but
not ex-
ceeding 500 volts, are performed,
the shorting link be-
tween the LO INPUT and ground
terminal must be re-
moved or damage
to the measurement source,
the Model
893,
or both may
occur.
2-22.
DC
DIFFERENTIAL
OFF-NULL INPUT
RE-
SISTANCE
2-23.
Input
resistance
of
the Model 893 is infinite at
null during dc differential measurements
because no
current flows between
the measured source and the in-
ternal reference
supply
of
the instrument. However,
a small current does flow
between the measured source
and the internal reference supply
whenever the instru-
ment is not exactly
nulled. For example, when the
meter deflection is
10%
of full-scale on
the 0. 001 volt
NULL SENS raxige, the
input resistance of the instru-
ment
is
10^^
ohms per
volt
of
the measured Input volt-
age or
10^2
ohms for an inpiit measured voltage of 10
volts dc. A graph of
these
apparent
off-null input re-
sistances is contained in Figure
2-4.
893A
Page 23
u oori
1x10^-
<0
METEE
DEFLECTION PESCENT
OF
END-SCALE
1
RANGE NULL SENS CURVE RANGE NULL SENS CURVE
1000 100
E 10 1 c
10
D
.
1 B
1
C
.
01 B
1
.
1
B
.001 A
100 10 D 1 . 1
B
1 C .01 A
.
1
B .001 A
1
. 01
B .001 A
Figure
2-4.
OFF-NULL
DC
I
NPUT RESISTANCES
2-24.
TVM
MODE OPERATION
2-25.
The Model 893
can be used on the
TVM mode to
measure ac
volt^es
from
one millivolt to 1100
volts ac
or dc
voltages from 10
microvolts to 1100 volts dc
with
an accuracy of
±3%
of the selected range.
To operate
the
instrument on the TVM mode,
perform the
opera-
tions outlined
in the Preliminary (Iterating
Procedures
(paragraphs
2-9
and 2-10) and
proceed as follows:
a.
Place
the MODE switch
to the AC or +DC
position
that corresponds
to the
measurement source.
b.
Connect the
circuit to be measured
between the HI
and LO
INPUT termiisals. K
one side of
the voltage
source is
grounded, connect the
grounded side to
the LO INPUT
terminal.
c. Place
the RANGE switch to the lowest range pos-
sible that
maintains
an
on-scale meter deflection.
The meter
deflection multiplied
by
the RANGE
switch petition is the value of the measured
voltage.
Left or
right meter deflection during dc measure-
ments corresponds to a negative or
positive polar-
ity
of
the measured dc voltage.
d. Measurement of
ac
or dc voltages from
0.
02 to 0.
volts is accomplished
on
respective NULL
SENS
switch
positions
of
0.
001
to 0.
l. In
this applica-
tion, the RANGE switch is placed to the 1 VOLT
rai^e and
the Readout dials
to .
000 The re-
sulting meter deflection multiplied by
the
NULL
SENS
switch position is the value of the
measured
voltage.
2-26. DIFFERENTIAL MODE OPERATION
2-27.
An
improved accuracy of up to 250
times over
that of the TVM mode is
obtained when the instrument
is
operated
as
a differential voltmeter. To
operate the
instrument as
an ac or
dc
differential voltmeter, pro-
ceed as follows:
a.
Determine the approximate value of the measured
voltage
by
performing the TVM mode
measurements
described in paragraph
2-9
and
2-10.
b. Place
the MODE switch to the respective dc
polar-
ity
observed on the TVM mode
measurement and set
the Readout dials
to the TVM measurement value.
K
an ac measurement is being made,
leave the
MODE
switch in its AC position.
c.
Place the NULL SENS
switch
to
successively high
null
sensitivity
positions
and
adjust the Readout
dials to obtain a center-zero meter
deflection.
Whenever the
NULL SENS switch is placed
to a position other than 'TVM
on the dc meas-
urement mode,
a voltage corresponding to
the Readout dial
indications is present
be-
tween
the HI and LO INPUT
terminals. A
personnel
hazard
does not exist
as
the
source resistance
is 90 megohms on the
ono A
Page 24
100 and 1000 volt ranges, however,
this
potential can damage high input impedance
semiconductor devices such
as
field
effect
transistors.
d. The Readout, dial digit indications correspond to the
magnitude of the measured voltage. If dc measure-
ments have been performed, the MODE switch po-
sition indicates the polarity of the
measured dc
voltage
2-28.
OPTIONAL RECORDER
OUTPUT
OPER-
ATION
2-29.
Instruments equipped with the
-02
option provide
an isolated recorder output
voltage
which
is available
at the
rear panel terminals. The recorder output dc
voltage
is adjustable from zero to ±0.
2
volts dc for
a
full-scale
meter
deflection and is used
to
drive
a center-
zero recorder. To utilize the recorder output voltage,
proceed as follows:
a. Connect the recorder to
the
rear panel RECORDER
OUTPUT
terminals.
The
LO
RECORDER OUTPUT
terminal is
connected to chassis ground of the Model
893. If
a
ground reference is undesirable,
q)erate the Model 893 on battery power with
its
line
cord disconnected
from
line
power.
b. Turn the recorder on and place the Model 893 con-
trols to the following positions:
POWER ON/LINE-OPR
RANGE 10
NULL SENS 1
MODE +DC
Readout dials 1 . 00 W
c. Connect the shorting link between the HI and LO
INPUT terminals and adjust the RECORDER OUT-
PUT LEVEL control for the desired left full-scale
indication on the recorder. The
left full-scale
meter
is
now plotted and from this information the
right full-scale point
can be
determined.
d. Remove the shorting link from between the HI
and
LO INPUT terminals and proceed with the desired
measurement. The external recorder will now
re-
cord
all
meter excursions of the Model
893.
2-30.
APPLICATIONS
2-31.
INTRODUCTION
2-32.
The Model 893 AC DC Differential Voltmeter,
because of its calibrated meter end-scale and high dc
mode input impedance, can be used in many special
applications. These applications,
to mention a few, are;
measurement
of
ac or dc voltage excursions about
a
nominal value, measurement of extremely high resist-
ances, operation
as a
dc null detector, and measure-
ment
of DBM.
2-6
2-33.
MEASUREMENT OF
VOLTAGE EXCURSIONS
ABOUT
A NOMINAL VALUE
2-34.
Whenever the instrument
is operated on the dif-
ferential
mode, the meter end-scale is calibrated
to be
a
known voltage by the position
of the NULL
SENS
switch, thus allowing rapid
determination of
any volt-
age
excursions about
a nominal value. For
example,
by selecting a null sensitivity of
, 1
with
the
RANGE
switch
on any voltage
range, the full left or right
scale
meter deflection represents
±0. 1 volts deviation
from
the Readout dial settings. To
measure voltage
excur-
sions about a nominal value, proceed
as follows:
a. Perform the Preliminary
Operating Procedures
of
paragraph
2-9
and
2-10,
b.
Determine
the nominal value of the
ac or dc volt-
age
being
measured, using the
TVM mode on the
Model
893. Refer to paragraphs 2-24
and
2-25
for
the TVM mode operating
procedures.
c. Place the Readout dials to the nominal
value of the
voltage
measured
in
step b and select
the desired
full-scale
meter sensitivity with the
NULL SENS
switch. The voltage
excursions about the Readout
dial settings can
now be determined by
the
left
or
right
meter deflections.
2-35.
MEASUREMENT
OF EXTREMELY
HIGH RE-
SISTANCES
2-36.
The Model
893 can be used as a megohmmeter
for measurements of high
resistances from 10 to 10
®
megohms with a typical accuracy
of ±5%, To operate
the instrument
as a megohmmeter,
perform the Pre-
liminary Operating Procedures described
in paragraphs
2-9
and
2-10
and proceed
as
follows:
a.
Place the
Model 893 controls to the following posi-
tions
:
POWER
ON/LINE OPR
RANGE
10
NULL
SENS
.
01 (.
001 if the
R
is
greater than
10^®)
MODE +DC
Readout dials
0. 00 00
The 10 volt range
has been used only
as
an
example in
step a. Other
voltage ranges
may
be
used to provide high resistance
measurements
at different voltage
levels.
b. Connect the unknown resistance between
the HI and
LO INPUT terminals.
Use
short
isolated leads to
prevent measuring the leakage resistance between
the
leads.
c. Rotate the Readout dials to
obtain
a meter deflec-
tion of
-1
and use the following calculations
tn de-
termine the value
of
the
unknown resistance.
893A
Page 25
ay3A
Figure 2-5. BRIDGE DETECTOR
-
FLOATING
SUPPLY
Gm
')
Rjj
»
Unknown resistance
=
Null detector input resistance
of 10
megohms
for NULL SENS
settings of
. 01. Null detec-
tor
input resistance is
100
megohms on
all
other
settings.
Ej.q
=
Readout dial
voltage
E-n
=
Meter deflection in volts (Proportional to se-
lected NULL SENS).
2-37. OPERATION AS A NULL DETECTOR
2-38. The Model
893,
because of its high input im-
pedance
on the dc differential mode, can be used
to
monitor small
voltage differences in bridge circuits,
potentiometers, and
other measurii^ devices.
In
most
of these applications, the
circuits
are adjusted
for
a
zero deflection or null on the Model 893.
Equipment
connections for two types of null detector configurations
are
illustrated in Figure
2-5
and
2-6.
To operate the
instrument
as
a null detector, perform the
Preliminary
Operatii^ Procedures described in paragraphs
2-9
and
2-10,
and proceed as follows:
a.
Select the
desired equipment applications illustrated
in Figure
2-5
and
2-6
and
make the appropriate
connections.
b.
Hace
the Model 893 MODE and NULL SENS
switches
to
the +DC and desired null detector
sensitivity
Figure
2-6.
BRIDGE
DETECTOR
-FLOATING
NULL DETECTOR
positions,
respectively. Adjust the circuit beir^
measured for a zero
or null deflection
on
the Model
893.
2-39. MEASUREMENT OF DBM
2-40.
'Ihe
Model
893,
when
operated
on
either the TVM
or
Differential AC mode, can be used as an
output
meter^ For this
application, the outpiri: to be measured
must be terminated
into
a
600 ohm load and the Model
893 INPUT connected
across the 600 ohm
load.
The
Model
893 is then operated on
the
TVM or
Differential
AC mode and
the resulting deflection or Readout
dial
indication
converted to DBM using the information con-
tained in
Figure
2-7.
For DBM measurements above
one volt ac,
multiply the voltages listed in Figure
2-7
by
ten for
each
range and
then
add
20 DBM for each
range.
INDICATED VOLTAGE
DBM LEVEL FOR
1
VOLT
RANGE
(1
mw into 600G)
.0975
-18
. 1227
-16
.
1545
-14
.
1946
-12
.
2450
-10
.3088
-8
.3897
-6
.4887
-4
.
6150
-2
.7746 0
.9752
+2
Figure
2-7.
1 VOLT RANGE DBM CONVERSION TABLE
2-7
Page 26
Page 27
3-1. INTRODUCTION
3-2. The
theory of
operation for the Model 893
AC-DC
Differential
Voltmeter is contained in this section of the
manual. A block
diagram analysis is used to functionally
describe
the overall operation of the
instrument which is
then followed by a detailed
circuit description
of
each
particular block
section. The
functional block diagram is
illustrated in Figure
3-1
and the schematic diagram is
contained at the rear of
the manual.
3-3.
BLOCK DIAGRAM ANALYSIS
3-4. INTRODUCTION
3-5, The Model 893
circuitry
is
comprised
of a refer-
ence
supply,
a
Kelvin-Variey divider,
a
dc input divider,
an ac converter, a
null detector,
a
meter, and optional
recorder output. This circuitry is interconnected by
various switching
arrangements when performing
the
desired ac
or
dc
conventional or differential voltage
measurements.
3-6. CONVENTIONAL TVM MODE
3-7.
When the
instrument
is
used as a conventional
transistorized dc voltmeter,
the circuitry is connected
as
illustrated in Figure
3-1.
The input divider
is con-
nected across
the input terminals of the
instrument to
provide a constant
input impedance of 100
megohms on
all
raises.
With a
full-scale input voltage applied to the
inpiri: of the instrument,
the selected tap of the input divid-
er provides a dc ii^ut voltage of ±
one millivolt to the in-
put of the null detector
which
drives
the front panel meter.
Gain of the null
detector is precisely controlled by the
negative feedback network and
provides
a
full-scale meter
deflection for any full-scale input.
Positive
or
negative
voltage
measurements are facilitated by reversing the
meter terminals
through the contacts of the
MODE
switch.
3-8.
By placing the
MODE
switch of
F^re
3-1
to the
AC position, the
instrument
circuitry is
connected
as
a
conventional transistorized ac voltmeter. The
resistor
R12 and
the
ac
converter are connected across the biput
terminals of the instrument and provide a
constant input
impedance of one megohm on all ac voltage
ranges. The
ac
converter
is
an operational amplifier driving a full-
wave
detector whose overall gain is controlled by
the neg-
ative feedback network selected with the
RANGE switch.
A
full-scale
input
voltage
at the input terminals of the
instrument results in an ac
converter output voltage
of
one volt dc which
is applied
to
the input of the null detec-
tor. The null detector, whose gain is
precisely con-
trolled by
the negative feedback network, drives
the front
panel meter which indicates
the magnitude of tlie measured
ac voltage.
3-9. DIFFERENTIAL NULL MODE
3-10.
When the instrument
is used
as a dc
differential
voltmeter, the
MODE
and
NULL SENS switches of Fig-
ure
3-1
are
placed to their respective
±DC
and
the desired
full-scale meter sensitivity positions.
On this mode of
operation, the NULL SENS
switch selects
a
suitable re-
sistance
value from
the
input divider
resistors to deter-
mine the meter
full-scale sensitivity and
also applies
the Kelvin- Variey divider
output to the common
input of
the
null detector. The dc input voltage
applied to
the
instrument is then compared by
the null detector
to the
Kelvin-Varley divider
output voltage and any
resulting
difference used to drive the meter.
Any right or
left
meter deflections correspond to an input
voltage above or
below
the Kelvin-Varley divider output
voltage.
The
Page 28
RECORDER
OUTPUT
Figure 3-1. MODEL
893A/AR BLOCK DIAGRAM
Kelvin-Varley divider voltage polarity and the meter ter-
minals can be reversed through the contacts of the MODE
switch for ± dc voltage measurements.
3-11.
By placing the MODE switch
of Figure
3-1
to the
AC position. The instrument
circuitry is connected as
an ac differential voltmeter having
an inpvit Impedance
of
one megohm. The
ac converter operates
in the
same manner as on the AC TVM mode
and supplies
a
full-scale input
voltage
of
one volt dc to the
dc meas-
urement circuitry. The
remaining circuitry
operates
similar to the dc differential mode
with the only dif-
ference being the absence of the
polarity reversal
switching.
3-12.
OPTIONAL
RECORDER
OUTPUT
3-13.
The c^tional
recorder output provides isolation
between the ndll detector output and
recorder output. The
null detector aitput voltage is
modulai:ed by a 3 kHz drive
s^nai derived from the
reference supply. The modulated
signal is transformer
coupled to
a
demodulator driven
at
the same
3 kHz rate as the modulator. The s^nal is
then
demodulated,
and tlie
resulting dc voltage
applied
through
a variable resistor to the recorder
output terminals. The
variable resistor
provides adjustment of the full-scale
recorder output
voltage.
3-14.
CIRCUIT ANALYSIS
3-15. INTRODUCTION
3-16.
The circuitry contained in the Model
893
is com-
prised of
a
power
supply
/battery charger,
a
reference
amplifier and
a
reference inverter,
a
Kelvin-
Varley divid-
er, an ac
converter,
a
null detector, an
optional recorder
3-2
output,
a meter, a dc irput divider, and RANGE, NULL
SENS,
MODE and POWER switches.
These circuits
will
be described in detail in the following
paragraphs using
simplified
circuit diagrams in addition
to the functional
schematic
diagrams located at the
rear of the manual.
3-17. POWER
SUPPLY/BATTERY
CHARGER
3-18. The
input power transformer T1
receives 115
or
230 volts ac through the
contacts of the POWER
switch
S2BR-2. The
primary of T1 is
constructed in such
a
manner
as
to
allow the instrument to
be operated from
115 volts ac, windings in
parallel, or 230
volts ac, wind-
ings in series.
Switch
85
performs the required 115 or
230 volt
ac power connections
in the primary
of
Tl. Fuse
FI protects the circuitry
from overloads. The
secondary
of Tl has four t^s which
si
5
>ply ac voltages to the power
supply and battery
charger. The ac voltage
present at
pins 8 and
10 are full-wave rectified
by diodes
CRl
and
CR2
and capacitors Cl and C2 located
on
the
A2
Reference
Amplifier Assembly.
3-19. On
instruments equipped with
the
-01
option, the
ac voltage present at
pins 9 and 11 of
Tl
is fuHwave rec-
tified by diodes CR3
and CR4 and applied across R9 and
BTl. When the POWER
switch is placed to the BAT CHG
position, the
contacts of S2BF
by-pass
the
resistor
R9
to
provide
a
maximum charge current
for BTl. The lamp
DSl functions
as a ballast to limit charging current at an
optimum
value for rapid charging of BTl.
Resistor
R9
is placed in the circuit on
all
other POWER
switch pos-
itions
to provide trickle-charging
of
BTl wiien the
instru-
ment is operated
from line power. Checking
of
BTl
is
provided
when the
POWER switch
is
placed
to
the BAT
CHK position. Switches
S2BR-1, S2BR-2, S2BF, S2AF,
and
S2AR provide
the necessary circuit connections that
remove the ac volt^e applied to Tl
and place the meter
893A
Page 29
in series
with
A2R4, The meter and A2R4 are also placed
in
parallel with the series-pass
transistor A2Q2 with the
POWER switch,
thus providing a check of BTl under an
actual load condition.
3-20. THE REFERENCE
SUPPLY
3-21. GENERAL.
Reference voltages of
1.
1,
11,
110,
and 1100
volts dc, upon
which the stability of the
instru-
ment
relies, and
a
3 kHz
output
signal
are produced by
the Reference
Supply. The
circuitry
of
the Reference
Supply consists of
two regulator stages and a
dc-dc con-
verter. A block diagram
of these
circuits is illustrated
in
Figure
3-2.
3-22. BLOCK DIAGRAM
DESCRIPTION.
The dc to dc
converter
regulator provides a
pre-regulated voltage
to the zener
current
regulator
and a
regulated voltage
to the dc
to
dc
converter. The zener
current regulator
provides
a
closely
regulated dc current for
the refer-
ence
zener diodes of CR3 and CR4
from which
the
1,
and 11
volt dc reference
voltages are derived.
These
same
zener diodes also
provide
a
stable
reference
voltage for
the dc to dc
converter comparison
ampli-
fier.
The
dc
to dc converter
produces the 110 and
1100
volt dc reference
voltages and a 3
kHz drive signal.
The reference divider
junction provides a
sample of
the 110 and 1100
volt
dc
reference
voltage to the dc
to
dc
converter
comparison amplifier
which controls
the
input dc
voltage to the dc to dc
converter. Conse-
quently, a
stable 110 or 1100
volt dc reference
voltage
related
to the zener reference
voltage is obtained.
The
3
kHz drive signal
is used to produce
operating voltages
for
null
detector,
ac
converter, and optional
recorder
output
circuits.
3-23.
CIRCUIT DESCRIPTION. The unregulated dc
voltage
from
the
power supply or
the
dc
output voltage
of the battery pack is applied to terminal 3 of the Ref-
erence Amplifier Assembly. This voltage is used
to
provide
an
input dc voltage to the dc to dc
converter
regulator circuitry. Initial turn-on
of
the dc to dc
converter regulator circuitry
is
accomplished with the
circuitry
comprised of A2R1, CRl, CR2,
CRSand
Q4.
The
voltage developed at the junction of R1 and
CR5 forward
biases CRl and transistor
Q4.
Conduction
of
Q4 is
initially
tlirough the low impedance
path of CR2,
thus providingadc input voltage to the zener
current
regulator. The resulting zener reference voltage biases
the
comparison amplifier
circuitry
of
Q3, Q5,
and
Q6
into conduction.
As
the
dctodc
converter regulator
output approaches
the
nominal +18.
5 volt dc level, di-
odes CRl and CR2 are
reversed biased, disconnecting
the turn-on circuitry from
the regulator circuitry.
Transistor
Q4
then functions as
a
buffer
amplifier be-
tween the
series-pass
driver
Ql
and
the comparison
amplifier output from
Q5.
3-24. The zener current
regulator circuitry
is com-
posed of transistors
Q7
through
Q9,
zener
diodes CR3
and CR4 and associated resistors.
Transistor
Q7
is
the
series-pass element
while resistor
R13
provides
starting current to
initially turn-on
the reference
ele-
ments of
CR3 and CR4. The
resistive network
of R17
through
R19 form a divider
across the output
of the
zener current
regulator and
provides
a
sample
of its
output
voltage to the
base of
Q9. Resistor
R19 provides
adjustment
of the output voltage
of the
zener current
regulator.
Transistors
Q8
and
Q9
coxnprise
a differ-
entially
connected
comparison amplifier
with the zener
voltage
of
CR3 and CR4 providing
a
reference at
the
base of
Q8.
This
reference voltage
has a
very low
temperature
coefficient
from which the
instrument
3-3
893A
Page 30
derives its measurement stability. The
output of the
differential connected
comparison
amplifier
controls
the
conduction of
the
series-pass
transistor
Q7
and
determines the output voltage of the zener
current reg-
ulator. This output voltage
establishes a
fixed current
through the zener diodes of CR3 and CR4.
Two
resistive
dividers comprised of
R26
through R3l and R32
through
R36 are
connected
across
the
zener
diodes of CR3 and
CR4. The
divider composed of R26
through R31 is used
to
provide a reference
voltage to the
dc
to dc converter
comparison amplifier
Q3.
The divider composed of
R32
throi^h
R36 is used
to
produce
the
1.1
and
11
volt
dc reference voltage applied to the Kelvin-Varley
divider
on
the
1 and 10
volt
ranges of
the instrument.
Variable
resistor R26 provides adjustment of the dc
to
dc con-
verter regulator output voltage while
R33 and R35
pro-
vide adjustment of the
1. 1
and
11
volt dc reference
voltages.
3-25.
The dc to
dc
converter regulator
circuitry is
comprised of transistors
Ql
through
Q6 and
associated
resistors
and capacitors.
Transistor
Q2
is
the
series-
pass element
whose conduction is controlled
by
the
series-pass driver
Ql and
the two differentially
con-
nected
conqjarison
amplifiers of
Q3,
Q5
and
Q6.
Tran-
sistor Q3 receives
a
reference
voltage
through R25
from the previously
described zener current regulator.
A sample of the Reference Inverter
Assembly dc
out-
put
voltage
present at terminal 8 is developed across
R21
and R22 and applied to the other base
Q3.
Tran-
sistor
Q3
compares
the
sample of the Reference In-
verter Assembly output
voltage to the zener reference
voltage
and amplifies any resulting difference. Tran-
sistors
Q5
and
Q6
comprise the second stage
of
the
comparison amplifier and amplify
any
resulting voltage
difference detected
by
Q3.
The output of
Q5
is applied
to the
series-pass driver
Ql
through the
common-base
buffer
Q4.
The
series-pass driver controls
the base
current
of
Q2
which in turn determines the output voltage
of
the
dc to dc converter regulator
and
consequently,
any resulting output voltage
of
the Reference Inverter
Assembly.
3-26.
The output voltage
of
the
dctodc
converter
regulator
is applied to terminal
3 of
the
Reference In-
verter
Assembly. This voltage is used to provide oper-
ating
voltages
for
the
3 kHz transformer coupled
multi-
vibrator
composed
of
Ql, Q2
and Tl. A low-pass
filter
comprised
of Rl, Cl and C2 provides decoupling of any
3 kHz variations that
could be applied back
to the reg-
ulator circuitry.
Resistor
R2
provides the dc current
to the
bases of
Ql
and
Q2
necessary to initially start
the multivibrator.
Diode CRl functions as a clamper
and
capacitor
Cl bypasses CRl
to
provide a low resist-
ance source to the teses of
Ql and Q2.
Upon application
of
an
input
dc
voltage,
assuming
that
Ql
will conduct
harder than
Q2,
the
collector of Ql clamps
the
upper
end of
the
center-tapped winding of Tl to zero volts dc.
The
base-drive winding associated
with
R3 applies a
positive goii^ signal
to the
base of
Ql,
driving
the tran-
sistor into saturation. The lower end
of
the center-
tapped winding is driven to +36 volts dc by autotrans-
former action causing the base-drive winding associated
with
R4
to apply
a
negative going signal to the base
of
Q2
cutting-off the transistor. This condition will persist
for a period
proportional to the flux capacity
of
the
3-4
transformer core, which
in
this
case is
approximately
150
microseconds.
At the
end of this period, the volt-
ages across the transformer
windings are reversed by
the
collapsing lines
of flux, driving transistor
Ql
into
cut-off
and Q2
into saturation,
thus establishing the
second half-cycle
of
the
3
kHz
signal.
The resulting
3 kHz
signal is
then
coupled
to
the secondary of Tl
where
it
is used
to
provide drive signals
and
the 110
and 1100 dc reference voltages. Variable resistor
R5 provides a mans of reducing
any
capacitive coupling
effects to the winding in the shield
of
Tl.
laductor Ll
increases the
circuit switching time
to
reduce higher
frequency radiation.
3-27.
The
secondary signals of Tl
that
are
available
at terminals 6
through 10 of the Reference
Inverter
Assembly are
used
to
provide drive signals
to the Null
Detector and
optional
Recorder
Output circuitry. Two
full-wave voltage doublers in
the
remaining secondary
windings of
Tl product the
110 and
1100 volt dc refer-
ence
voltages used by the Kelvin-Variey divider.
These
voltages are used on
the
100 and 10000
voltage ranges of
the instrument. The full-wave voltage doubler
composed
of CR3, CR4, R6 and
C4 through C6 produces
the 110 dc
reference voltage available
at terminal 2 of the Refer-
ence
Inverter Assembly. Resistor R14
provides
adjust-
ment of this reference
voltage. The full-wave
voltage
doubler composed of
CR4 through CR7,
R7
through Rll
and C7
through
C9 produces
the
1100
volt dc reference
voltage available at terminal
1
of the Reference
Inverter
Assembly.
Resistor
A2R26
provides
adjustment of
the
resulting input voltage.
A
resistive divider
comprised
of R9
through
Rll
provides
a
load for the
voltage doubler
when this reference
voltage is not being used and
func-
tions as a
bleeder when power is removed
from the
circuit. Regulation of the 110 and 1100
volt dc refer-
ence
voltage
is
accomplished by feeding a sample
of
the
selected reference voltage back to
the
dc to
dc
converter
regulator circuitry. Switches SlAR-1 and
SlAR-2
select
the
desired sections of a
resistive
divider com-
posed of Rl2
through
Rl6 and
the resistors R21 and R22
located in the Reference
Amplifier Assembly.
This
sample of the output reference
voltage controls
the level
of
the input
voltage
applied
to the
3
kHz
multivibrator
which determines the level of
the secondary
voltages
of
Tl
and
in turn controls the
output level of
the full-
wave voltage doublers used to develop
the 110 and
1100
volt
do
reference voltages.
3-28.
KELVIN- VARLEY DIVIDER
3-29. GENERAL.
Continuous division of the reference
supply
voltages, while presenting
a constant load to
the
reference supply, is accomplished with
a Kelvin-Variey
divider. The
divider is composed of matched fixed
re-
sistors Rl
through
R34, trimmers
R35 and R36,
poten-
tiometer R37
and
rotary
switches S6 through S8.
3-30.
CIRCUIT DESCRIPTION. Rotary
switch S6
controls the first
order division of the reference sup-
ply voltage. The first resistive
divider of Rl
through
R12 is arranged in 12 equal parts
of lOOK. ohms.
The
contacts of S6 connect the
200K ohm effective resistance
of the second divider in
parallel
with the
selected
two
parts
of
the first divider,
thus producingaselected
resistance value
of lOOK ohms. This selected re-
893A
Page 31
oaoA
sistance
value
is
in
series
with the remaining ten lOOK
ohm parts of the
first
divider and presents
a
constant
load
resistance
of 1. IM
ohms to the reference supply.
There
are eleven equal voltage steps available from
the first divider
which
can be selected by
the rotary
switch
S6.
Since the reference supply output voltage
is either
1.
1,
11,
110,
or
1,
100 volts dc, the rotary
switch
S6
is
calibrated
in 0.
1,
1,
10,
or 100 volt in-
crements.
3-31.
The
second,
third,
and
fourth
order
divisions
of the reference supply
voltage
are provided by
the
corresponding resistive dividers R13
through
R23, R24
through
R34,
and
potentiometer
R37.
The
second and
third
order
dividers function in
a
manner similar to the
first
order
divider with their associated switches
S7
and S8 performing
the desired connections. Each of
these dividers are composed of
11
equal value resistors,
thus providing
ten equal divisions of the preceding di-
vider
output voltage. Potentiometer
R37
comprises
the fourth order divider
which operates
on
the same
principle as the
preceding
dividers
but
provides a
con-
tinuously variable
output voltage at its
wiper.
Re-
sistors R35 and R36 provide
the
necessary
trimming
resistance for
the fourth order divider.
3-32. The
voltage
appearing at
the
wiper
of R37
is the
output voltage of
the Kelvin-
Varley divider. This
volt-
age
directly corresponds
to
the readout dials digit value
for
the particular reference supply voltage being used.
The RANGE switch S1AF2 selects the appropriate ref-
erence supply
voltage
of
1.
1, 11,
110,
or 1100 volts
dc corresponding
to the
1, 10,
lOO, or 1000
volt
ranges
of the instrument. The NULL switch S3AF applies
the
Kelvin-
Varley
output voltage to the null detector common
on the various null ranges of the instrument. When-
ever
the instrumait
is operated on the TVM mode, S3AF
disconnects the output of the
Kelvin-Varley
divider from
null detector common
and
connects the low input com-
mon
to null detector common.
Reversal
of the Kelvin-
Varley
output
voltage
polarity is provided
by
the MODE
switches S4AF1 and S4AF2.
3-33.
AC CONVERTER
3-34. GENERAL. 'The
AC Converter clianges measured
ac voltages to dc voltages that
can be
measured with
the dc portion of the instrument. Circuitry of the AC Con-
verter consists of
a
transconductance aii^lifier coirprised
of
Ql
through QlO and the feedback networks
selected with
the RANGE switch, a symmetrical half-wave
detector CR3
and CR4, and the power supply CR5 and
CR6. A
block
diagram of these circuits Is illustrated in Figure
3-3.
3-35. BLOCK DIAGRAM DESCRIPTION.
AH qperatlng
voltages for
the AC Converter are produced by
the half-
wave rectifiers CR5 and
CR6 and tteir associated filters.
A
3
kHz signal derived from
the Reference Inverter As-
senJ^ly
is
used
to
drive tte half-wave rectifiers,
hiput ac
voltages applied
to
the AC Converter are amplified by
the
transconductance airplifier coriprised erf Ql
through
QlO.
The resulting
transconductance amplifier output current
flows through the
symmetrical half-wave detectors wiiich
in turn produce a full-scale
output
voltage erf
one volt dc.
This
dc
voltage is then applied to the dc
measurement
circxiitry of the instrument for measurement.
A voltage
proportional to the
transconductance amplifier output
current is fed back to the anplifier input
througli a feed-
back network selected with the RANGE switch to establish
a
high
degree of gain stability
and
provide ac
rar^u^ for
the instrument.
3-36. CmCUIT DESCRIPITON. The
iiput circuit erf the
AC
Converter is conposed of R12 and
a
capaetty conpen-
sator which maintains
a
high input
inpedance erf
cxie
meg-
ohm shunted
by less
than
20
pf for all ac ranges. Over-
load
prctection
for the
AC
Converter is provided by diodes
CRl
and
CR2. The
input stage of
Ql
is a field effect
transistor
(FET)
utilized for its high input inpedance and
low noise features. The common-emitter stages
of
Q2,
3-5
Page 32
Q4,
Q5,
and
Q7
provide
the
necessary
voltage gain of
the
ac s:^nal.
Emitter-follower
0^
is the dynamic load
at
the amplifier output.
Feedback from the emitter of
Q7
through QlO
stabilizes the current and
voltage gain
of the amplifier. Transistors
Q2
and
Q9
provide a
low-
impedance bias voltage
for their associated
circuitry.
Linearity compensation at
the
d
3
mamic load oi±put is pro-
vided through
Q8.
Loop gain
of the
amplifier is
stabil-
ized
with the filters Cl, Rll and
C25, R44 selected
with
the
RANGE switch S9BR-2. The output
s^nal coupled
through C12 drives the
diodes CR3 and CR4
through their
cross-over
region very rapidly, thus
producing very low
cross-over distortion.
The signal develq)ed
across R125
is
fed
back to the
input of the AC Converter
through the
feedback network selected
with the RANGE switch
S9BR-1
and causes a
current directly
proportional to the ac
input
s%nal to flow
through CR3 and CR4.
The resulting dc
voltages are then filtered by
C13 and Cl4 and
applied
through the MODE switch S9 to
the
dc
measurement
section
of
the instrument. Calibration
of the ac voltage
ranges
of
the instrument is
accomplished with the
variable
resistors
R29, R30, R32, R34, variable
capacitors C21
and C22, and the
capacity compensator located
across
R12.
3-37.
The3kHz drive signal applied
between A7 ter-
minals 6 and
7
is
half-wave rectified
by
diodes CR5 and
CR6.
The resulting dc
voltages
are
then
reduced and
filtered with
R40, R4l, C23, and C24 to
provide the
±12
and
±10
volt dc pperattog vottages for
the
AC Converter.
3-38.
NULL
DETECTOR
3-39. GENERAL. The Null Detector is a
chopper stabil-
ized
dc amplifier
usii^
an
insulated field effect transis-
tor as a chopper.
DC pperatii^ voltages for the
amplifier
are produced from a 3 kHz drive signal si?)plied
by the
dc-
to-dc converter, thus providing maximum isolation for
the amplifier circuitry free from power line frequency
variations and
harmonics. Circuitry
of the
Null Detector
consists of
a
power sxippiy, an 84 Hz multivibrator, a
chopper driver,
a
chopper, a low-pass filter,
a
carrier
amplifier,
a
synchronous demodulator and a meter. A
block diagram of these circuits is illustrated in
Figure
3-4.
3-40. BLCX:K diagram DESCRIPTION. AU
operating
voltages for the Null Detector circuitry are provided by
the power supply
comprised
of half-wave rectifiers
CR3
and
CR4. These ±6.
8
volt dc voltages are produced from
a 3 klfe drive
s%nal developed in the Reference Inverter.
The 84 Hz multivibrator provides chopper
and
demod-
ulator
drive voltages at
a
rate asjmchronous to the power
line
frequency. Input dc voltages applied to the null de-
tector u
5
)ufc are passed through a low-pass filter to
reduce
any normal mode
hriierference and then squarewave modu-
lated at
a
84 Hz rate by the
chopper
Ql,
The chopper
driver Qll
provides a 84 Hz drive signal to the gate
of
the chopper and a cancellation signal to
the
drain.
This
cancellation signal is
180°
out of
phase
with
the chopper
gate signal
and provides cancellation of any spikes gen-
erated internally
in the chopper
Ql.
The
carrier amp-
lifier is
conprised of five st^es
whose gain is controlled
by
negative emitter feedback.
Any amplified ac
annals
are
then demodulated
by
the synchronous
demodulator
Q8
which is driven in synchronism
with the chcpper
Ql.
The
resulting dc voltage is then used to drive the front
panel
meter to indicate
both the polarity and magnitude the
input voltage on the
TVM
mode or the off-null
magnihide
on
the
NULL
mode.
Negative feedback through the meter
to the null detector input determines the overall gain of
the null
detector.
3-6
Figure
3-4.
NULL DETECTOR
BLOCK DIAGRAM
Page 33
3-41. CmcmT
DESCRIPTION. 'Die
3
kHz drive signal
applied
to terminal 8 of the
Null Detector Assembly is
half-wave rectified to
provide ±6. 8 volt dc operating vol-
tages for
the mill detector
circuitry. Diodes CR3 and
CR4 along
with C17 through Cl9 and
R33
and
R34 form
the
half-wave rectifiers used to
produce the dc operating
voltages.
Synchronous drive voltages for the null
detector
circuitry are provided by
the 84 Hz collector-coupled
multivibrator con^rised of
Q9,
QiO,
Cl4, Cl5, and R23
through
R26. The 84 Hz collector signal of
Q9
is used to
provide the
demodulator drive for
Q8.
Transistor
Qll
si^pltes
an 84 Hz squarewave from its
emitter to tlie gate
of Ql.
This signal is derived from the
collector of QlO
in the 84
Hz multivibrator. Resistor
R27
provides ad-
justment of the squarewave
s%nal amplitude applied to
the gate of Ql.
The collector s^nal of Qll is
coupled by
C5 and C4 to the
output
of Ql
where it is used
to null
out any
spikes internally generated
in
Ql.
Adjustment of
this
corapensatirg signal is provided by
potentiometer
R31 located in
the collector circuit of Qll.
3-42. The resulting
squarewave signal present at
the
junction of
R3 and
Ql
is coupled by
C3 to the input stage
of
the carrier
amplifier.
This
signal is
proportional to
the
difference between any
feedback voltage from the
meter circxiit
and the input voltage at
terminal 2. The
carrier
amplifier is comprised
of four common-emitter
amplifiers of Q2
through
Q5
and complementary
push-
pull
output amplifier Q6 and Q7.
Negative emitter feed-
back
tlurough the network con^osed of
RIO and R15 through
R18,
C8 and
Cll controls the gain of the carrier amp-
lifier
and consequently the
null detector input
impedance.
Variable
resistor
R17
located in
the feedback
circuit
provides
adjustment of this ir^ut
in^edance. The emitter
signal of
Q6 and
Q7
is coupled by
C12 and R20
to
the
synchronous demodulator Q8.
Transistor Q8 is
driven
in
Synchronism with the
chopper
Ql
and Is operated in
the
inverse
mode
to secure minimum saturation
voltage.
The resulting demodulated
s^nal is filtered
by
the low-
pass
filter comprised of
R21
and
Cl3 and applied to ter-
minal 5 for
use in the cptionai
Recorder Output circuitry.
This same
voltage s^nal is applied through
R22 and the
meter circuit to Ql as a
negative feedback signal
to con-
trol the gain of the null
detector. Any current flow
through this network causes a
correspondir^ deflection
on
the meter
proportional
to the magnitude of the
null
detector
input voltage.
3-43. DC INPUT DIVIDER
3-44. GENERAL. Full-scale input voltages to the in-
strument on
either
mode
of cperation
are
reduced to one
millivolt
(±10%
overranging) at the kpik of the null detec-
tor by
the DC Input Divider circuitry.
3-45.
CIRCUir
DESCRIPTION.
The DC Input Divider is
con5)Csed of seven series
connected
resistors
Ri through
R7 that have a total resistance cf 100.
1
megohms. When
the instrument is operated in the TVM mode, the input
impedance
is a
constant 100 megohms on all dc voltage
ranges and the
RANGE
switch is used to select
the desired
tap c£
the divider i^twork. When the instrument
is
oper-
ated on the differential dc mode, the NULL and
RANGE
switches select
^^rious taps on the input divider network
to provide an
input impedance of 10 megohms on tte
.
001
and
.
01
NULL
switch
posttions, and
100
megohms on all
other NULL switch positions.
3-46.
OPTIONAL
RECORDER OUTPUT
3-47. GENERAL,
histruments
containing the
-02
Cption
are
provided with
a
RECORDER OUTPUT that is isolated
from the
null detector circuitry. The Recorder
Output
circuitry is composed of a
modulator and demodulator
separated
by
an
isolation
transformer. Each circuit is
driven at a 3 kHz rate by a
signal
derived from
the Ref-
erence Inverter
Assembly.
3-48. CIRCUIT DESCRIPTION. The dc input voltage
applied to terminal 1 of
the Recorder Output Assembly is
modulated at a 3
kHz
rate by
alternate conduction at
Ql
and Q2.
Conduction of
Ql
and
Q2
is controlled by
the
3
kHz drive s^nal applied to terminal 3. Transformer
T1 couples
the resulting signal to
its
secondary winding
where demodulation is accomplislied by alternate con-
duction of
Q3
and
Q4.
Conduction of
Q3
and
Q4
is con-
trolled by
the
3
kHz drive signal applied to terminal
4.
The resultii^ isolated dc
voltage
is
then filtered by Cl
and
RlO. Variable resistor RiO provides adjustment
of
the
RECORDER OUTPUT voltage.
3-7
893A
Page 34
Page 35
4-1.
INTRODUCTION
4-2.
This section of the raanxial contains the informa-
tion necessary for you to maintain your Model 893 AC-
DC Different^ Voltmeter. The
information is arranged
under
headings of "SERVICE
INFORMATION,
DISAS-
SEMBLY
INSTRUCTIONS,
GENERAL MAINTENANCE,
PRECALIBRATION AND
TROUBLESHOOTING,
and
CALIBRATION PROCEDURES.
"
A list
of
the test equip-
ment required for maintenance of this instrument is
contained in
Figure
4-1.
E the recommended
test
equip-
ment is not available,
other
instruments having
the
equivalent specifications may be
substituted.
4-3. Your instrument was completely tested and
aligned before
leaving the factory
and
calibration should
not
be
necessary durii^ the first 90 days of
operation.
However, should
you wish to check the instrument ac-
curacy
against most
of
the specifications contained in
Section I, the information contained in the Calibration
Procedures
may
be used. The Calibration Procedures
are arranged
in
such
a
manner
that
by disregarding
the
adjustment
information that
may
be used
as
Instrument
Performance
Checks.
4-4.
We recommend that you
thoroughly
read and
understand this section
of
the manual before attempting
any
maintenance
on
your instrument.
4-5.
SERVICE INFORMATION
4-6, Each instrument manufactured by
the
John Fluke
Mfg. Co.
,
Inc. is
warranted for
a
period of one year
upon
delivery to the original purchaser.
Complete
war-
ranty information is contained in
the Warranty
page
located at the rear of this manual.
4-7. Factory authorized calibration
and
repair
service
for all
Fluke instruments
are available
at
various world
wide locations. A
complete list
of
factory
authorized
service
centers
is
located at the
rear of this manual.
If requested, an
estimate
will be
provided to the
cus-
tomer before any repair work is begun on instruments
beyond
the warranty period.
4-1
SCi‘3 A
Page 36
EQUIPMENT NOMENCLATURE
SPECIFICATIONS RECOMMENDED INSTRUMENT
AC
calibration
Source
Lo distortion,
1 mv to 1000 vac,
20 Hz
to
100 kHz,
with an ac-
curacy of
. 02%
Hewlett Packard
Model
745
with
Com-
panion 1000
Volt Am-
plifier
DC Calibration
Source
0-1000
volts dc with an accuracy
of 0. 002%
Fluke Model
332B
Oscilloscope
Sweep range; 50 usec/cm
Vertical sensitivity: 5 mv/cm
Tektronix 531 with
Type
L Plug-In Unit
Probe
Passive 10:1
P6007
Multimeter
Ranges:
AC’O to 100 ma
0 to 300 vac
DC-0 to 100 ma
0
to 1000
vdc
OHMS
-
0 to 100 megohms
Accuracy:
AC-±1%
DC-±0.
1%
Fluke Model
853A
Differential
Voltmeter
Range
-
0 to 1000 vdc
Accuracy -iO.
06%
Input
Impedance
-
Infinite
at null
Fluke Model
895A
Figure
4-1.
REQUIRED TEST EQUIPMENT
4-8.
DISASSEMBLY INSTRUCTIONS
4-9. THE MODEL 893A
DISASSEMBLY
INSTRUCTIONS
4-10.
The foUowir^ procedure is to be used to gain ac-
cess to various parts of
the Model 893A:
a.
Remove the eight top dust cover
attaching screws
and remove
the dust cover from the
instrument.
b.
Remove the two screws from
the circuit board re-
taining strap
attached
access
the center of the instru-
ment and remove the strap.
This allows access
to
the
Null
Detector, Reference Amplifier,
Reference
hiverter, AC Converter, and
NULL
SENS
switch S3,
Ensure
that the retainer str^
insulators are
kept in a clean
condition.
c.
Remove the tc^ front and
rear trim strip
attaching
screws and remove
the trim strips from tte
instru-
ment.
This allows access to the front panel
binding
posts,
corrponents on the POWER switch S2,
and (if
the
-01
cption is installed) DSl.
The
printed circuit boards are inserted in
slide holders and will protrude approximately
three
inches when the instrument is inverted.
Place a strip of
tape across the chassis of
the instrument
to hold the printed circuit
boards in place if the instrument is to be
inverted.
d.
Remove the eight
lower dust cover
attachii^ screws.
This
allows access to the
Kelvin-Varley
Divider
Assembly.
e.
Remove
the lower front
and rear trim str^
attaching
screws
and remove the trip
strips from the instru-
ment.
This allows
access to the Kelvin-Varley
switches
S6 through S8
and potentiometer R37.
f. Remove the
left and right
knurled knobs from the
handle
assembly and
remove the handle
from the
instrument,
g.
Remove the
eight left and right
rear panel attaching
screws
and
slitte the
rear panel
free from the instru-
ment. This
allows access to tte
power transformer
Tl, CRl,
CR2 and any option
components.
h. Loosen
the front panel control
knob alien set screws
and remove the
knobs from the front panel. Loosen
the two screws
securing the shutter cablir^ to the
front panel and
then remove the nuts
on the front
panel
binding posts and
remove the terminal clips
from the binding posts. Remove
the left and right
front panel
attaching screws and
slide the front
panel
forward until free
of
the
instrument. This
4-2
893A
Page 37
allcfws
access to
the front panel
meter and ail switch
linkages.
i.
Remove
the
right or
left side
panel attaching
screws
and
remove
the
panel from
the instrument.
This
allows
access
to the
respective
MODE or
RANGE
switch.
CAUTIONl
Do not remove
both side
panels from
the
instrument at
the same
time or
the struc-
tural-strength
of the
instrument
will be
impaired.
4-11. THE
MODEL
893AR DISASSEMBLY
INSTRU::TXO)^S
4-12. The
following
procedure is to be used
to gain ac-
cess to
various
parts of
the Model 893AR:
a.
Remove the
six top
dust cover
attaching screws and
remove the
dust
cover from the instrument.
This
allows access
to the
mounting screws of
the Kelvin-
Varley Divider,
Reference
Inverter, and Null
Detector
printed
circuit boards.
b.
Remove the top
front
and rear trim strip
attaching
screws and
remove
the trim strips from
the instru-
ment.
This allows
access to the
front and rear
panel
components.
c.
Remove
the six
lower dust cover
attaching screws
and
remove the
dust
cover from the
instrument.
This
allows access
to the
Reference Inverter
and AC
Con-
verter printed
circuit
board mounting
screws, all
of the
switches used
in the
instrument, and
potentio-
meter R37.
d.
Remove
the lower
front and rear
trim strip
attacliing
screws
and remove
the
trim strips from the
instru-
ment.
This
allows further access
to the front
and
rear
panel
components.
e.
Remove
the left
and right rear
panel attacliing
screws
and slide
the rear
panel free from
the instrument.
This allows
access
to the power
transformer
Tl,
CRi, CR2,
and any
option components.
f.
Loosen the
front panel
control knob set
screws and
remove
all of the
knots from
the front
panel. Loosen
the two
screws
securing the
shutter cabling
to the
front
panel.
Remove the
nuts
from
the front
panel
binding
posts and
remove the
terminal clips from
the
binding posts. Remove
the left
and right front
panel
attaching screws and
slide the
front panel for-
ward until free
of the
instrument.
This allows ac-
cess to the
front panel
meter and
all switch linkages.
4-13.
GENERAL
MAINTENANCE
4-14.
PERIODIC
CLEANING
4-15.
Ihis
instrument is
completely
enclosed,
therefore
no entry for
dirt.,
dust, or
lint is provided.
Consequently,
it
is usually
only
necessary to
clean the exterior
of the
instrument.
To clean the
exterior, use a
cloth moistened
with
anhyndrous ethyl
alcohol or Freon
T.
F.
Degreaser
(iVK
180
Miller-Stephenson
Chemical Co.
,
Inc.
).
If
eitlier
of
these cleaning
agents are
not readily available, soap
and
water, applied
sparingly to a
cloth can be used to
clean the
exterior of
the instrument.
4-16. If it
becomes
necessary
to
clean the
interior
of
the
instrument,
a
hot
deionized or
distilled water rinse
followed by a
thorough
drying should be used.
Drying
temperatures
in excess
of
160°
should be
avoided.
CAUTIONl
The use of
solvents,
particularly keytones,
is not
recommended because of
possible
damage
to the
dielectric materials used
in
the instrument.
4-17. FUSE
REPLACEMENT
4-18.
Input line power
to the
Model 893 instruments
is
fused
to
i/8
ampere
by FI.
This fuse is
located on
the rear
panel assembly
of the instrument in a
bayonet
fuseholder.
When replacing
this fuse use a l/8A,
250
volt, slo-blo, type fuse.
4-19. BATTERY
REPLACEMENT
4-20. Battery
replacement on instruments containing
the
-01
option is
necessary when 16 continuous
hours
of
battery charging will
no longer result in a satisfactory
battery check.
To replace
the
batteries, proceed as
follows:
a.
Obtain access
to the battery pack installed on the
rear panel using
the disassembly procedures for
your
particular instrument that are described in
paragraphs
4-8
through
4-12.
b.
Unsolder red (or white) and black
battery pack wires
from
their
respective circuit connections and wrap
the exposed ends of
the wires with electricians tape.
c.
Remove
the four nuts
and screws that
attach the
battery pack
to the rear
panel and lift the
battery
pack
free
from the instrument.
d.
Locate and
replace the
defective batteries
observing
proper
polarities of
connections.
e.
Mount the
battery pack on
the rear panel
assembly
using
the screws
and nuts
removed in
step c.
f.
Remove
the tape from
the black
battery pack
wire
and
solder this
wire to the
terminal on
the power
transformer
from
which it
was
removed in step
b.
g.
Remove
the tape from
the red (or
white)
battery
pack
wire
and solder
this wire to the
end of the
resistor from
which it was
removed
in step b.
n. Reassemble
the
instrument and
check the
batteries
as
described in
Section II
paragraph
2-9
and
2-l0.
4-3
8 9.3 A
Page 38
4-4
Figure
4-2,
ADJUSTMENT
AND TEST POINT LOCATIONS (Sheet 1
of
4)
893A
Page 39
07
A2TP15
A2TP12
A2TP13
A2TP10
A3R14
A3R8
A3TP18
A3R5
A3TP17
A3TP15
A3R14
A3R8
A3TP18
A3R5
A3TP17
A3TP15
Figure
4-2. ADJUSTMENT AND TEST
POINT
LOCATIONS {Sheet 2 of
4)
9/22/71
4-5
ono 4
Page 40
A4TP15
A4TP14
A4R3]
A4R27
A4TP9
A4TP11
A5R36'
Figure
4-2.
ADJUSTMENT
AND
TEST
POINT LOCATIONS (Sheet
3 of
4)
893A
Page 41
Figure
4-2.
ADJUSTMENT AND TEST
POINT
LOCATIONS (Sheet 4
of
4}
4-21.
PRECALIBRATION AND
TROUBLESHOOTING
4-22.
INTRODUCTION
4-23.
Before attempting to calibrate the Model 893 AC-
DC
Differential Voltmeter,
a
parameter check of the
major
sections
of
the instrument circuitry
should be
performed. These precalibration checks,
when
the
desired results
are
obtained, will ensure
that
each
major
section of the instrument is
contributing
the
least
possible error
toward overall instrument inac-
curacy.
Wlien
performing these checks it
may
become
necessary
to replace
component parts in order to ob-
tain the desired
results. Under
these circumstances,
general
troubleshooting of
the circuitry is necessary.
As
each
malfunction is corrected,
a
complete recheck
of
the
particular circuitry
involved is also necessary.
4-24. Hie following tests should be
performed in
a
draft
free area at an
ambient
temperature
of
21°
to 25°C.
Adjustment and
test point locations are
illustrated
in
Figure
4-2.
At the
beginning
of
each check the type
of test
equipment is given. Refer
to Figure
4-1
for
the
recommended test
equipment.
4-25. REFERENCE
AMPLIFIER/REFERENCE IN-
VERTER CHECKS
4-26.
The Reference Amplifier/Reference Inverter
Checks require
an autotransformer,
an ac ammeter,
2/10/75
an
oscilloscope and
a dc
differential
voltmeter. Cir-
cuit
waveforms are illustrated in Figure
4-4.
To per-
form
the checks,
proceed
as
follows:
a. Remove
the upper
and lower dust covers from the
instrument. Refer to paragraphs
4-8
through
4-12
for disassembly instructions.
b. Make the equipment
connections illustrated in
Figure
4-3
and place the Model 893
controls
as
follows:
POWER
ON/LINE
OPR
RANGE
1000
NULL SENS
lOV
MODE
+
Readout dials
00.
0 00
c.
Apply 115 volts ac,
50-500 Hz, through the auto-
transformer
to the Model 893. The ac
ammeter
should indicate less than 45
miliiaraperes.
d. If your instrument is equipped with the
-01
option,
place the POWER switch to BAT CHG, observii^
that the ac ammeter
indication
does not exceed
60 milliamperes and
the
ballast lamp DSi illumi-
nates.
e.
Connect the oscilloscope
signal input to terminal 3
of the Reference Amplifier Assembly and connect
the
oscilloscope ground
to terminal
6 or 7. The
4-7
89.3 A
Page 42
waveform observed on
the
oscilloscope
CRT should
not
exceed a
peak-to-peak indication
of 2. 5
volts.
f.
Disconnect the oscilloscope from
the
Model 893.
g.
Connect the input of the dc differential
voltmeter
to
TP14
of
the A2 Reference
Amplifier
Assembly
and connect the common lead to A2
terminal
6 or 7.
The voltmeter should indicate +19
±0. 5
volts dc.
h. Remove
ac power from the
Model
893
and connect
the
dc differential
voltmeter input to terminal
2 of
the A5
Kelvin-Varley Divider
Assembly.
i. Reapply ac power
to the
Model
893,
observing
that
the dc
differential voltmeter indicates
1100
±0. 13
volts dc.
j.
Rotate A2R26 to
each
available
limit,
observing that
the dc
differential voltmeter
indication changes
by
at least
±0.
2 volts.
k.
Adjust A2R26 for an
indication
of 1100 volts dc on
the
dc
differential voltmeter.
l. Decrease
the
ac
input voltage
applied to the
Model
893 to 103. 5 volts ac
with
the autotransformer
con-
trol.
The voltage
observed on
the
dc differential
voltmeter
should not vary more
than
±0. 0055 volts.
m. Increase
the
ac
input
voltage applied
to the
Model
893
to
126. 5 volts ac with the
autotransformer
control. The
voltage observed
on the dc
differ-
ential voltmeter
should not
vary more than
±0. 0055
volts.
n. Remove ac
power from
the
Model
893 and
connect
the
dc
differential
voltmeter
input to A2TP9.
0
.
Reapply
115 volts ac to the
Model
893,
observing
that the
dc differential voltmeter
indicates
17 ±0. 01
volts
dc.
p.
Rotate
A2R19 to each
available limit,
observir^
that
the dc differential
voltmeter indication
changes
by at least
AlOO millivolts.
q.
Adjust
A2R19 for an indication
of +17 ±0.
01
volts dc
on the
dc differential voltmeter.
r. Place the RANGE switch to 100
and connect the
dc
differential voltmeter input to
terminal 2 of the
A5
Kelvin-Varley
Divider Assembly.
s.
The
dc differential voltmeter
should
indicate
110
±0. 009 volts dc.
t. Rctate
A3R14
to
each available limit,
observing that
the
dc differential
voltmeter indication
changes
by
at
least ±0. 010 volts.
u.
Adjust A3R14
for an
indication
of
110 volts dc
on
the
dc differential voltmeter.
v.
Place the RANGE switch to
10,
observii^ that the dc
differential voltmeter indicates
!1
±0.0009 volts dc.
4-8
1
MODEL 853A
Figure
4-3.
REFERENCE AMPLIFIER/REFERENCE INVERTER
CHECKS
-
EQUIPMENT CONNECTIONS
w.
Rotate A2R33 to
each
available limit,
observing
that the
dc differential
voltmeter
indication
charges
by at
least
±
one
millivolt.
X. Adjust A2R33
for an indication
of
11 volts dc on the
dc differential
voltmeter.
y.
Place the
RANGE switch to
1,
observing that
the
dc differential voltmeter
indicates
1.1
volts dc
±0.
9 millivolts.
z. Rotate
A2R35 to each available
limit, observing
that
the dc differential
voltmeter indication
changes
by at least
±1
millivolt.
aa. Adjust A2R35
for
an indication
of
1 . 1
volt
dc on the
dc differential
voltmeter.
ab. Connect the dc differential
voltmeter
common to
terminal
1
of the
A4 Null Detector
Assembly and
the input to TP17.
ac. Place the
Model 893 NULL SENS switch to the TVM
position and the RANGE
switch to the
100
position.
ad.
The
dc differential voltmeter should
indicate
-6.
8
volts dc ±400 millivolts.
Record the exact
value.
ae. Place the
Model 893 RANGE
switch to the 1000
position.
af. Rotate
A3R8 to each available limit,
observing
that the dc differential
voltmeter
indication
chaises
by at least
±15 millivolts.
ag. Adjust A3R8
for an indication
on the dc differential
voltmeter that
is within 10
millivolts of the voltage
recorded in
step ad.
9/22/71
893A
Page 43
ah. Connect the oscilloscope signal
input
and
ground
to A3 terminals 10 and
9,
respectively. A 3
kHz
drive signal having a maximum amplitude of 13.
5
volts
peak-to-peak should be observed on the oscil-
loscope
trace.
10
megohm
1%
resistor. Circuit
waveforms are illus-
trated in
Figure
4-6.
To
perform
the
checks, apply
ac power to
the instrument
and proceed
as follows;
a. Place the Model 893 controls
as follows:
4-27.
When
the results of
these checks agree
with the
information given, the
Reference
Amplifier/Reference
Inverter Assemblies are
functioning
properly
and the
test
equipment can be
disconnected from
the
instrument.
4-28.
NULL
DETECTOR/DIVIDER CHECKS
4-29. The Null
Detector
/Divider
Checks require
a dc
voltage calibrator, a dc
differential voltmeter and
a
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LINE OPR
1
.001
+
.00100
b. Connect the dc
differential voltmeter
input to TP16
and the common lead
to
terminal 7
of the Null
Detector Assembly. 'The voltmeter should
indicate
+6. 8 ±0.
4 volts
dc.
A2
REFERENCE AMPLIFIER WAVEFORMS
S
j
!
—
—
u
rs ft, ft
A
i rr
U-)
o
O
f
n
I
10 MSEC/CM 0.2
MSEC/CM
A2
TERMINAL 3
A2TP9
0.2
MSECyCM
A2TP14
A3 REFERENCE INVERTER WAVEFORMS
0.2 MSEC/CM
A3TP16
0.2
MSEC/CM
A3TP17
Model 893A S/N 123 thru 508
Model 893A S/N 1 23 thru
254
A3TP19
1
-• •>
K
**
r'
ri
0.2 MSEC/CM
JUNCTION OF
A3CR4 AND A3CR6
0.2 MSEC/CM
JUNCTION OF
A3CR5
AND A3C7
33M III
L_
0.2 MSEC/CM
JUNCTION OF
A3R8 AND
A3C9
Figure
4-4.
REFERENCE AMPLiFIER/REFERENCE
INVERTER WAVEFORMS
c. Connect
the
dc
differential voltmeter
input to TP17,
observing that the voltmeter indicates
-6.
8 ±0.4
volts dc.
d.
Disconnect the dc
differential voltmeter
from the
Model 893.
e.
Connect a shorting
jumper
between
the
LO and HI
INPUT terminals and rotate A4R27
and
A4R31 fully
counter-clockwise.
f.
Adjust A4R27 clockwise until a full-scale negative
meter
indication
(-1)
is
obtained
and
then
rotate
the control an additional
10°
clockwise.
g.
Remove
the shorting jumper
and adjust A4R31 for
an
exact zero-center meter
indicaticC^^id then
repeat steps f andgas
necessary.
h. Connect the shorting jumper
between the LO and HI
INPUT terminals and adjust
A4R5 to each available
limit. The meter pointer should
deflect above and
below the minus
1
indication.
i. Adjust
A4R5 for a full-scale
(-1)
indication
on the
meter.
j.
Remove the shorting jumper between the
INPUT ter-
minals and replace with
a
10
megohm
1
%
resistor.
k. Place the
Readout
dials to
.
002M and adjust
A4R17
to each available
limit,
observing that the
meter
pointer deflects above and below the
minus
1
indi-
cation.
1. Adjust A4R17 for
a
full-scale
(-1)
indication on the
meter.
m.
Remove the 10 megohm resistor
from
between
the
INPUT
terminals
of the instrument
and place
the
Model
893
controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LINE OPR
1
.001
+
.00000
9/22/71
4-9
893A
Page 44
n. Connect
the
output of the
dc voltage calibrator
between
the
LO and
HI INPUT terminals.
o. Apply
the dc
input
voltages versus the
ranges in-
dicated in
Figure
4-5, observing that the meter
indicates
full-scale
(+1)
± 1
-
1/2
small divisions.
4-30.
When
the results
of the
checks agree with the
information
given, the
Null
Detector and
Divider cir-
cuitry
are functioning
properly
and the test equipment
can be
disconnected
from the
instrument.
INPUT
DC VOLTAGE
RANGE
NULL
SENS
.001
1
1 mv
.01
1
. Olv
. 1
1
. 1 v
1.0
1 TVM
10.0
10
TVM
100.0
100
TVM
1000.0
1000
TVM
Figure
4-5.
INPUT DC
VOLTAGE
VERSUS
RANGE-CHECKS
4-31.
KELVIN-VARLEY
DIVIDER
CHECKS
4-32.
The Kelvin-
Varley Divider
Checks require
the
use
of
a
dc voltage
calibrator.
The
Precalibration and
Troubleshooting
Checks of
paragraphs 4-21 through
4-30
must also have
been performed
to
ascertain that
the
associated
Instrument
circuitry
is functioning
correctly.
To perform
the checks,
apply
ac power
to the
instrument
and proceed
as follows:
a.
Place the Model 893
controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LTNE
OPR
10
.001
+
10.
000
-
A4TP11
FULL-SCALE INPUT
Ft"".
;
5
u
SATURATION
CONDITION
4
1
:ffz
5
u —j
C
-
—
c
T...
u
A4TP13
A4TP15
Note:
HORIZONTAL
SWEEP
-
5
MSEC/CM
Figure
4-6.
NULL DETECTOR
WAVEFORMS
4-10
b. Apply
+10
volts
dc from
a dc voltage
calibrator
between
the
Model 893
LO
and HI
INPUT
terminals.
c.
Adjust
A2R33
for a zero-center
meter
indication
on the
Model
893
d. Apply the
dc
input
voltages
versus the
Readout
dial
settings
of Figure
4-7, observing
that the
Model
893 meter
indicates
zero-center
within the
major division
deviation.
INPUT
DC VOLTAGE
READOUT
DIAL
SETTINGS
MAJOR
DIVISION
DEVIATION
11.000
10. 99
X
±5.5
10.
000
10.00
0
null
reference
10. 00
9-99
X
±5. 0
9.999
9. 99
90
±4. 99
8. 888
8. 88
80 ±4,
44
7.777
'^77
20
±3. 88
6.666
6.66
^
±3.33
5.555
5.55
5(}
±2.77
4.444
4.44
40
±2.
22
3,333
3-33 30
±1,
66
2.222
2,22
20
±1.
n
1.111
1. 11 10
±
.55
1.000
1.00
Q
±
.5
Figure
4-7.
INPUT
VOLTAGES
VERSUS
READOUT
SETTINGS
-
CHECKS
4-33.
When
the results
of these
checks
agree with the
information
given, the
Kelvin-
Varley Divider
circuitry
is
functioning
properly
and the
test equipment
can be
disconnected
from the
instrument.
4-34.
RECORDER
OUTPUT
OPTION
CHECKS
4-35.
The
Recorder
Output
Option Checks
require
the
use
of a dc
differential
voltmeter.
Circuit
wave-
forms
are illustrated
in
Figure
4-8,
To
perform the
checks,
apply
ac power to the
instrument
and proceed
as
follows;
a. Connect the
inputs
of a dc differential
voltmeter
to
the
rear panel
HI and
LO
RECORDER OUTPUT
terminals and
rotate the
associated
level control
fully clockwise.
b. Connect
a shorting
jumper between
the
LO and
HI
INPUT
terminals
of the
Model
893
and
place the
controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout
dials
ON/LINE
OPR
1
.001
+
.00100
c. A
dc voltage
of
-0.
2 to
-0.
28 volts
dc should be
indicated
on the
dc differential
voltmeter
connected
to the
RECORDER
OUTPUT
terminals.
893A
Page 45
d. Rotate the
RECORDER OUTPUT
level control
counter-clockwise,
observir^ that
the RECORDER
OUTPUT voltage
decreases
to zero volts.
e. Adjust the
RECORDER OUTPUT level
control for
an indication
of 0. 2 volts on the dc
differential
voltmeter.
4-36. When the results of these checks agree with the
information given, the Recorder Output Option circuitry
is functioning properly and
the
test
equipment
can be
disconnected from the instrument.
4-37. AC CONVERTER CHECKS
f. Place the
Model
893
Readout
dials to
.
00010,
ob-
serving that the
RECORDER OUTPUT
voltage in-
dicated on the
dc differential
voltmeter is
-0.02
volts dc.
BASE OF
Q1
or Q2
1
7^
iI
1m 1
i1
1 1
1 1
i
m 11 11HH
1
h
[ 1
.i MSEC
u
FULL SCALE
INPUT EMITTER
Q
1 or
Q2
EMITTER Q3 or
Q4
BASE Q3 or
Q4
Figure 4-8.
RECORDER OUTPUT WAVEFORMS
4-38.
The AC Converter Checks require an ac calibra-
tion source,
an oscilloscope, and
a dc differential volt-
meter. Circuit waveforms are illustrated in Figure
4-10.
To perform the checks, apply ac power to the
instrument
and proceed as follows:
a.
Place the
Model 893
controls
as
follows:
POWER
RANGE
NULL
SENS
MODE
Readout dials
ON/LINE
OPR
1
.001
AC
1
.
000 00
b.
Connect the dc differential
voltmeter input to A7
terminal 7 and its common lead to A
7 terminals
The voltmeter should
indicate 12 ±0. 2 volts
dc.
c. Connect the voltmeter
input
to
the junction of
R41
and CR5, observing that the voltmeter indicates
10
±0.5 volts dc.
d. Connect the voltmeter input to A7 terminal
6,
ob-
serving that the voltmeter indicates
-12
±0. 2 volts dc.
e. Connect
the
voltmeter
iiput
to the junction of R42 and
CR6,
(^serving that the voltmeter indicates -10±0.
volt dc.
Disconnect the voltmeter upon
completion
of this step.
f.
Apply
a calibrated one
volt
ac signal at 400 Hz
between the
LO
and HI INPUT terminals of the
instrument.
g.
Connect the oscilloscope input to the emitter of A7Q6
and the ground
lead
to A7 terminal
5,
Hie signal
o!>
served on
the oscilloscope CRT
should be
identical
to tlie full scale
AK^
emitter waveform illustrated
in Figure
4-10.
E necessary, adjust A7R35 to oWain
a
meter indication
of 0±0.5 major divisions.
h. Apply
a
calibrated 0. 1 volt ac signal
at
400
Hz to
the
n^UT
of the Model
893,
observing that the
wave-
form displayed on the oscilloscope CRT
is identical
to the A7Q6 l/lO scale input
waveform illustrated
in Figure
4-10.
i. Perform the RANGE checks described
in Figure
4-9
at
400 Hz, observing that the
specified results are
obtained.
If necessary, adjust the associated adjust-
ment to obtain the specified
meter
indication.
j.
Perform the AC Converter RANGE
checks described
in Figure
4-9,
disregarding the
adjustmeit and meter
indicatiorB, at frequencies of
20
Hz, 20 kHz,
50 kHz,
and 100 kHz. TTie waveforms observed
on the
oscil-
losccpe CRT
should be consistant with the peak-to-
peak levels of
A7Q6
illustrated in Figure 4-10.
9/22/71
4-11
893A
Page 46
MODEL
893 AC RANGE
A7Q6 EMITTER
MODEL 893 METER
A7 ADJUSTMENT
INPUT VOLTAGE
WAVEFORM
INDICATION
10
10
FULL-SCALE 0
±0.
5
m. d.
R33
100
100
FULL-SCALE
0 ±0.
5
m. d.
R31
500 1000*
50% OF THE
FULL-SCALE
WAVEFORM
AMPLITUDE
0
±1
m. d.
R29
Set the Readout dials to 500. OQ
Figure 4-9. AC
CONVERTER
RANGE
CHECKS
400HZ FULL-SCALE INPUT
0
X
V,/
r
V-
L/
t
/
/
N
5
u
A7Q6 EMITTER
1
MSEC/CM
400HZ 1/10 SCALE INPUT
r
, L
\
: ^
~r
[ST'
\
X.
)
\
/
V.
S
lO
o
A7Q6
EMITTER
1 MSEC/CM
400HZ
FULL-SCALE INPUT
dt
1
r
s
CR4/R24 IMSEC/CM
400H2
FULL-SCALE
INPUT
CR3/R21
IMSEC/CM
400HZ
FULL-SCALE INPUT
Q
/
\m
!
T
/
\ /
r
\
[
\ j
V 7
2
u
CN
o
R23/C15 IMSEC/CM
Figure
4-10.
AC
CONVERTER WAVEFORMS
4-39.
When the results of these
checks agree with
the
information given, the AC Converter
is functioning
prop-
erly
and
the test equipment
can be disconnected
from the
instrument.
4-40.
CALIBRATION
PROCEDURES
4-41. INTRODUCTION
4-42.
The Model 893 should be checked
for
calibration
every 90 days. Before attempting to calibrate your
instrument, it is recommended that the
major portions
of the instrument circuitry
be checked using the methods
described in
the
preceding
Precalibration and Trouble-
shooting paragraphs.
4-48,
It will be necessary to apply ac and dc voltages
from a known accurate source to the input of the instru-
ment during the calibration process. An ac calibration
source such
as
the H.P. Model 745A can be used to obtain
the accurate ac voltages, and
a
John Fluke Model 332B
can
be used
to obtain
the required dc voltages.
4-44. Calibration of the instrument shoxild
be performed
on line power with
the
top and bottom dust covers removed
from tte instrument. An ambient room ten^erature
from
2l°C to 25'’C, in
a
draft free area, should
be maintained
during the
calibration
process.
Adjustment
and testpoint
locations are illustrated in Figure
4-2.
Figure
4-11
contains a list of the calibration adjustments and their
effects.
4-45.
METER MECHANICAL
ZERO ADJUST
4-46. With
the power removed
from the Model
893,
proceed as follows:
a.
Position the instrument
horizontally (normal
pos-
ition) on the bench.
b. Adjust the meter mechanical zero
screw, acces-
sible from
the
front panel, until the meter pointer
indicates zero-center.
Back-off the
screw
adjust-
ment just enough to
disengage the cam once the
center-zero indication
is obtained.
4-12
893A
Page 47
CIRCUITRY
1
ADJUSTMENTS
AND THEIR
EFFECTS
ZENER REFERENCE
SUPPLY
A2R19 Used
to adjust for
17i0. 01 volts do
at A2TP9 and has
a minor effect
on
instrument
calibration.
Adjustment of this control
establishes
a specific voltage
for the zener
diodes which minimizes
the zeners
temperature
coefficient
and increases their
voltage stability.
NULL DETECTOR
A4R27 Adjusts
the gate
signal drive level of
Ql for optimum chopping
efficiency.
Inadequate drive to
the gate of
Ql
will
result in a lower
than specified
null detector
input resistance
and a lower
gain.
Excessive
drive to
the gate of
Ql
(clockwise
setting)
will reduce the
;
null
detector stability.
;
A4R31
Adjusts the level
of the signal applied
to the drain of
Ql.
This signal
is used to
cancel out the
null detector open-circuit
offset effects
produced
by the
gate to drain capacitance
of
Ql. Misadjustment of
this control
will produce
null detector
open
circuit
offsets particularly
notieable on the
.001 volt sensitivity.
A4R5
Adjusts the
null detector gain
to compensate
for variations
in the
carrier
amplifier gain,
full-scale
meter sensitivity, and
feedback
resistor
tolerances.
A4R17
Adjusts the
carrier amplifier gain which
determines the
input
resistance
of
the null
detector and to
a minor degree
affects null
detector sensitivity.
A3R8 Adjusted
to provide
uniform null detector
voltages of ±6.
8 volts dc on
all voltage ranges.
This adjustment
does not affect instrument
calibration.
A3R5
Adjusted to reduce the
3 kHz common
mode signal from
A3T1
that
is present
at the common terminal
of the null detector.
This adjust-
ment
does not affect instrument
calibration.
KELVIN-VARLEY
:
DIVIDER
A5R36
Provides
a means of trimming
the full-scale
vernier dial range to
compensate for
potentiometer resistance
tolerance,
1000 VOLT
RANGE A2R26
Adjusts
the value of the
reference voltage
for
the
+18.5
volt dc
regulator to
a value necessary to calibrate
the 1000
volt range.
Adjustment
of this resistor
will also effect calibration
of tr»e
lOO
volt
range but does not
effect the
1
and
10 volt range calibration.
100 VOLT RANGE
A3R14
Adjusts the ilO
volts dc applied to the
Kelvin-Varley Divider on the
lOO volt range.
Adjustment of
this resistor will not
effect the
calibration
of any other
voltage range.
10
VOLT RANGE
A2R33
Adjusts the 11 volts
dc applied to
the Kelvin-Varley
Divider
on
the
10 volt
range. Adjustment
of this resistor
will not effect the
calibration
of any other
range.
1
VOLT RANGE
A2R35
Adjusts
the
1. 1
volts
dc applied to the Kelvin-Varley
Divider on the
1
volt
range. Adjustment
of this resistor
will not
effect
the cali-
bration of
any other range.
1000
VOLT AC RANGE
(400
Hz)
A7R29
Adjusts the AC Converter
gain at low frequencies
on the
1000 volt
ac range. Adjustment
of this resistor will
not affect calibration
of any other voltage
range.
100 VOLT AC
RANGE
(400
Hz)
A7R31 Adjusts the AC
converter gain
at
low
frequencies on the
100 volt ac
range. Adjustment
of this resistor
will not affect calibration
of any
other
voltage range.
Figure 4-n.
SUM/Vu4RY OF CALlBRATiON
ADJUSTMENTS (Sheet 1
of
2)
4-13
8 93
Page 48
CmCUITRY
ADJUSTMENTS AND THEIR, EFFECTS
100
VOLT AC RANGE
(50
KHz)
STRAY
CAPACITY
COMPENSATOR
Adjusts the AC Converter gain
at
high frequencies
on the 100
volt
ac range.
Adjustment
of this compensator will affect
high frequency calibration of all other ac ranges.
100
VOLT AC RANGE
(50
KHz)
A7C15 Adjusts the high
frequency
response at l/lOOO of full-scale
on the 100 volt ac
range.
Adjustment of this
capacitor
affects
calibration of all
other
ac ranees.
10 VOLT AC RANGE
(400 Hz)
A7R33 Adjusts the
AC
Converter
gain
at low frequencies on the 10
volt ac
rai^e. Adjustment of this resistor will not affect
calibration of any
other voltage
range.
10 VOLT AC RANGE
(50 KHz)
A7C21 Adjusts the AC Converter gain at high frequencies on the 10
volt
ac
rai^e. Adjustment of this capacitor will not affect
calibration of
any other voltage range.
1 VOLT AC
RANGE
(400 Hz)
A7R35 Adjusts the
AC
Converter
gain
at
low frequencies on the
1 volt
ac range.
Adjustment of this resistor will not affect calibra-
tion of any other voltage
range.
1
VOLT AC RANGE
(50
KHz)
A7C22 Adjusts the AC Converter gain at high frequencies on the
1
volt
ac
range.
Adjustment of this capacitor will not affect
calibration of
any
other voltage range.
AC CONVERTER A7R4 Adjusted to provide
a
dc bias of +1. 5 vdc across
A7C16
in the
AC
Converter.
Figure
4-11.
SUMMARY
OF
CALIBRATION ADJUSTMENTS
(Shee» 2 of
2)
4-47.
ZENER
REFERENCE SUPPLY
CALIBRATION
4-48.
To
calibrate the Zener Reference Supply,
apply
ac power to the instrument
and proceed
as follows:
a. Place the
Model 893 controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LINE OPR
1
TVM
-f-
.OOOOfi
b. Connect
a
dc differential voltmeter to A2TP9
and
adjust A2R19
for an indication of +17 ±0. 01 volts
dc.
c. Disconnect
the dc differential voltmeter.
4-49.
NULL
DETECTOR CALIBRATION
c. Adjust A4R27 clockwise until negative
(-)
deflection
of the meter pointer reaches
a maximum and then
continue
an additional 10
°
clockwise.
d. Remove the INPUT terminals shortir^ jumper and
adjust
A4R31
for a meter pointer indication of zero
center
±1/2
small divisions.
e.
Connect
the shorting jumper between the LO
and
HI
INPUT terminals
and adjust A4R5 for an exact
full-
scale
(-)
meter pointer indication.
f. Replace
the
shorting jumper between the
INPUT
terminals with a
10
megohm
1%
resistor and place
the Readout dials to
,
00200.
g.
Adjust
A4R17 for an exact full-scale
(-1)
meter
pointer
indication.
h.
Repeat
steps e through
g
until the specified
results
are obtained.
4-50
To calibrate
the Null Detector circuitry,
proceed
as follows
a. Place the
Model 893 controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout
dials
b. Connect
a
shorting
jumper between the LO
and HI
INPUT
terminals and rotate A4R27 and A4R31 fully
1.
counter-clockwise.
4-14
Replace the resistor between
the INPUT
terminals
with
a
shorting
jumper.
On each RANGE and
NULL SENS switch
setting,
place the Readout
dials to the voltage indicated
on
the
NULL SENS
switch, observing that the
meter
pointer
indicates
full-scale
(-1)
±2 small division.
On the one volt
range, perform the
checks
in both
positions of the
POLARITY switch.
Remove the
INPUT terminal shorting
jumper and
place the NULL
SENS switch to TVM.
Apply the dc
voltages
to the
Model 893 INPUT
terminals on the
ranges indicated in Figure 4-12,
ON/LINE
OPR
1
.001
+
.00105
893A
Page 49
observing
that
the meter pointer
indicates
a cor-
responding
positive
or
negative full-scale
(±1)
±1
small division.
INPUT DC VOLTAGE
(±0.
3%)
RANGE
±1 1
±10 10
±100 100
±1000 1000
Figure 4-12. TVM RANGE CHECKS
in.
Remove
the
dc
input voltage
and connect a dc dif-
ferential voltmeter between A4TP17
and
the
LO
INPUT
terminal.
n.
Place the RANGE
switch
to 100 and the Readout
dials to 00. 000 and record the dc differential volt-
meter
indication.
0 .
Place
the RANGE switch to 1000
and adjust A3R8
for a
dc voltage
within
±10 millivolts of the
voltage
recorded in step n.
p.
Disconnect
tte
dc
differential
voltmeter
and connect
an oscilloscope
ground lead to the
LO
INPUT ter-
minal
and the input lead to terminal
1
of
the
A4
Null
Detector
Assembly.
q.
Place
the RANGE switch to 1000 and the Readout
dials
to
100.
QS.
Adjust
A3R5 for
minimum
ampli-
tude of
the
3
kHz squarewave
observed on
the
oscilloscope
CRT.
4-51. KELVIN- VARLEY DIVIDER CALIBRATION
4-52.
To
calibrate the Kelvin-Varley
Divider,
apply
ac
power
to the instrument and proceed
as
follows:
a.
Place
the
Model 893 controls
as follows:
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LINE
OPR
10
.001
0.01 00
b. Apply a dc
input
voltage between the
LO and HI
INPUT terminals
and adjust its
level
to
obtain a
zero-center
meter pointer indication.
c. Place the Readout
dials to 0. 00
X
and
adjust A5R36
for a
zero-center
meter pointer
indication.
4-53. DC VOLTAGE RANGE CALIBRATION
4-54.
To calibrate the
DC
Voltage Ranges of the Model
893,
apply ac power to the instrument
and
proceed
as
follows:
a.
Disconnect the shorting
link from the
LO INPUT
terminal and place the
Model
893
controls
as
follows;
POWER
RANGE
NULL SENS
MODE
Readout
dials
ON/LINE
OPR
1000
.
1
+
1000. 00
b. Apply a dc calibration voltage
of
1,
000 ±0. 002%
volts dc between the LO and HI INPUT
terminals
and center the adjustment A2R26, observing that
the
Model 893
meter
indicates
center-zero
±6
md.
c. If the result
of
step
b
is obtained, proceed with
step
f. If
the
desired results are not obtained,
perform steps
d
through
f.
d.
Remove ac power
to the instrument
and connect
the
jumpers
illustrated in Figure
4-13
between
their
respective
circuit board
connections.
e. Reapply ac power to the instrument and, using the
information
provided in Figure
4-14,
clip
the
cor-
responding
jumper
or jumpers.
A B
Figure
4-13.
JUMPER
WIRE LOCATION
9/22/71
4-15
8 9.3 A
Page 50
METER
INDICATION
JUMPER WIRE
0
to ±0. 6
NONE
-0.
6 to
-1.
8
B
-
1
. 8 to
-3.
A
-3.
0 and above BOTH
Figure
4-14. JUMPER WIRE
SELECTION
f.
Adjust A2R26
for an
exact
zero-center meter
indication,
g.
Reduce the
calibration voltage to
100 ±0. 002%
volts
dc and
place the RANGE switch
to
100,
h. With
the
NULL
SENS switch to 0.
01,
adjust A3R14
for an
exact zero-center
meter pointer indication,
i. Reduce
the calibration voltage to 10 ±0,
002%
volts
dc and
place the RANGE switch to 10.
j.
With
the
NULL
SENS switch to
.
001,
adjust A2R33
for
an exact center-zero meter
pointer indication,
k.
Reduce the
calibration voltage to 1
±0. 002%
volts
dc and
place the RANGE switch
to
1.
l. With the NULL
SENS switch
to
.
001,
adjust
A2R35
for
an
exact zero-center meter pointer
indication.
m.
Reduce the
calibration voltage to 80 millivolts ±0.
1%
and place
the RANGE switch
to
100.
n. Place the
Readout dials to
00. OSQ,
observing
that
a
zero-center meter
indication is obtained within
±1/2
of
a
small
division on the vernier Readout dial.
0
.
If
the results of
step n
are
not obtained, adjust
the
vernier
Readout dial for an
exact zero-center meter
indication and
loosen the set screw
that
secures
the
vernier dial
indicator to the potentiometer
shaft. Refer
to Figure
4-15
for
location of the set
screw.
MODEL
893AR
MODEL
893A
SET
Figure 4-15,
VERNIER DIAL SET SCREW
LOCATION
4-55.
AC
CONVERTER CALIBRATION
p.
Position the
vernier dial
indicator
for a
front panel
indication of
80 and securely
tighten the set screw.
4-56. To calibrate the
AC Converter,
apply ac power
to
the instrument and proceed as
follows:
q.
Remove the
calibration voltage
from the Model 893
and place a
shorting
jumper between the LO and HI
INPUT
terminals.
r. Place the Model 893
controls as follows:
POWER
RANGE
NULL
SENS
MODE
Readout dials
ON/LINE OPR
10
.
001
+
00. 000
s.
Rotate
the vernier Readout dial until a full-scale
(-1)
meter pointer indication is obtained, observing
that the vernier Readout dial indication is between
9 and 11.
a.
Place the
Model 893 controls
as
follows:
POWER
RANGE
NULL SENS
MODE
Readout dials
ON/LINE OPR
100
0.
AC
100.
00
b. Apply
a
calibrated 100
volts ac signal at 400
Hz
between the HIGH
and
LD INPUT
terminals and ad-
just
A7R31
for a meter indication of zero-center
±1/2
major division.
c.
Apply
a calibrated 100 volt ac signal at 50 kHz
between the HI and LO INPUT terminals and adjust
the stray capacity compensator
slightly,
using
4-16
9/22/71
893A
Page 51
«yaA
an
insulated tool, for
a meter indication of
zero-
center
±1 major
division.
The stray capacity
compensator
is located between front
panel and
chassis of the instrument along
with R12. This
adjustment is
accessible from the top of the
Model
893A
and from the bottom of the Model 893AR.
CAUTION’
The 100
VAC
input voltage
is present on the
stray capacity compensator.
d. Set the Readout dials
to 01. 0
00
e.
Apply
a
calibrated one volt ac signal
at 400 Hz
be-
tween
the HI
and
LO
INPUT terminals. A
meter
indication of zero-center
±
one small
division should
be obtained.
f.
Apply a
calibrated one volt ac signal at 50 kHz
between the
HI
and LO INPUT terminals
and adjust
A7C15 for the
same meter indication obtained
in
step
e.
g.
Repeat steps
c
through
f until the specified
results
are
obtained.
h.
Set
the
Readout
dials
to 10 0.
0 (W and perform the
checks indicated in Figure
4-16.
MODEL 893 AC
INPUT VOLTAGE
METER
INDICATION
(±
MAJOR
DIVISIONS)
100
vac, 10 kHz
100 vac, 100 kHz
100 vac, 20 Hz
0
±1.5
m. d.
±2
m. d.'“
0
±7
m. d.
— 1 Ml 1
'
Figure 4-16. 100
VOLT RANGE CHECKS
1.
Place
the RANGE
switch to its
10 volt
range
position
and set
NULL SENS
TO .001.
j.
Apply
a calibrated 10 volt ac signal at 400 Hz
between
the HI
and
LO INPUT
terminals and
adjust A7R33 for
a meter deflection of zero-center
±1/2
major
divisions.
k.
Apply
a calibrated 10 volt ac signal at 50 kHz
between
the HI and LO INPUT
terminals and adjust A7C21
for
a
meter indication of zero-center
±1/2
major
divisions.
1. Perform the
10 volt range checks indicated in
Fig-
ure 4-17, observing tliat the specified
results are
obtained.
MODEL
893 AC
INPUT’ VOLTAGE
METER INDICATION
(±
MAJOR
DIVISIONS)
10
vac, 10 kHz
10 vac,
100 kHz
10 vac, 20 Hz
0
± 1.5
m. d.
0
±
2 m. d.
*
0
±7m. d..
*NULL SENSE
TO.
Figure
4-17.
10 VOLT RANGE CHECKS
m. Place the
RANGE
switch to
its
1 volt
ranee
position
and set
NULL
SENS TO
.001
n.
Apply
a
calibrated
one volt ac signal
at 400 Hz
be-
tween
the
HI
and LO INPUT
terminals and
adjust
A7R35
for
a
meter indication
of zero-center
±1/2
major divisions.
o. Apply
a calibrated one volt
ac signal at 50
kHz be-
tween the HI and LO INPUT
terminals and adjust
A7C22 for
a meter indication
of zero-center
±1/2
major divisions.
p.
Perform the
one volt range
checks
indicated in
Fig-
ure
4-18, observing that
the
specified
results are
obtained.
MODEL
893
AC
INPUT
VOLTAGE
METER
INDICATION
(±
MAJOR
DIVISIONS)
1
vac,
10 kHz'
1
vac,
100
kHz
1
vac,
20 Hz
0
±1.5 m.d.
0
±2.5 m.
d.*
0
±7 m. d.
*
NULL SENS
to
.
01
Figure 4-18. 1
VOLT RANGE
CHECKS
q.
Set the Pteadout dials
to . 10000
and perform tlie
range
checks contained in
Figure
4-19, observing tliat
the
specified results are obtained.
MODEL 893
AC
INPUT
VOLTAGE
METER
INDICATION
(±
SMALL
DIVISIONS)
0.1
vac, 400
Hz
0. 1 vac, 50
kHz
0
±1
s.d.
0
±3 s.d.
Figure
4-19.
1
VOLT RANGE
(0. 1 SCALE) CHECKS
r. Set
the
Readout dials to
.
00100
and perform
the
range
checks
contained in
Figure
4-20,
observing
that
the
specified
results
are obtained.
MODEL 893 AC
INPUT VOLTAGE
METER
INDICATION
(±
SMALL
DIVISIONS)
0.001 vac, 50
kHz
0.001 vac, 400
Hz
0
±1 s,
d.
0
±1/2
s.d.
Figure 4-20.
1 VOLT RANGE (O.OOi
SCALE) CHECKS
s. Place the RANGE
switch
to its
1000 volt
range po-
sition and
set the Readout
dials
to
500. 00.
t. Apply a
calibrated 500
volt ac
signal
at 400 Hz be-
tween the HI
and LO INPUT
terminals
and adjust
4-17
2/10/75
Page 52
A7R29 for a
meter indication of zero-center
±1/2
imjor divisions.
u. Apply a
calibrated 500 volt ac signal at 10 kHz be-
tween the HI and LO
INPUT terminals, observing
tliat
the
meter
indicates zero-center ±1/2
major divisions,
V.
Set the Readout
dials to
10
00.
00
and apply
a
1000 volt
ac
s^nal at 10 kHz, observing that the meter indi-
cates zero-center
±5 major divisions.
4-57.
When the results of these calibration adjustments
are obtained,
the
Model
893 is fully calibrated, and the
test
equipment can be
disconnected
from
the instrument.
4-18
893A
Page 53
5-1.
INTRODUCTION
5-2.
This
section of the
manual contains
a listing
of replaceable
components for this
instrument. The
first listing
contains a complete
breakdown
of all
the
major assemblies
followed by subsequent
listings that
itemize
the
components on each
major
assembly. An
illustration
accompanies
each major
assembly listing
to aid in locating the
listed
components.
5-3.
Assemblies
and
subassemblies are
identified
by
a
reference
designation
beginning with the
letter A
followed by a number
(e.
g.
,
A1 etc,
).
Electrical
com-
ponents appearing
on the schematic
diagram
are iden-
tified
by
their
schematic diagram
reference
designation.
Components not
appearing on the schematic
diagram
are consecutively
numbered throughout
the parts
list.
These
components
are
identified
with
whole numbers on
the
arrow call-out
illustrations
and by index numbers
on the grid illustrations.
Flagnotes
are used through-
out
the parts
list and refer to
special ordering
explan-
ations that
are located in
close proximity to the
flag-
notes.
5-4.
COLUMN
DESCRIPTION
a. The REF DESIG column
indexesthe item descrip-
tion to the associated illustration.
In general the
reference
designations are
listed under
each as-
sembly in
alpha-numeric
order. Subassemblies
of minor
proportions
are sometimes listed with
the
assembly of which they
are a part. In this
case,
the
reference designations
for the
components of
the
subassembly
may appear out
of
order.
b.
The
INDEX
NO, column lists coordinates
which
locate
the designated part
on the associated
grid
illustrations.
c. The DESCRIPTION
column
describes
the
salient
characteristics
of
the component.
Indention
of
the
description indicates the
relationship to other
as-
semblies, components,
etc. In many
cases it is
necessary to
abbreviate in this
column. For ab-
breviations
and symbols used,
see
the
following
page.
d. The
ten-digit
part number,
by which the item
is
identified at the John
Fluke Mfg.
Co.
,
is listed
in the STOCK
NO. column.
Use this number when
ordering parts from the factory
or authorized
representatives.
e. The Federal Supply
Code for the item
manufacturer
is listed
in the MFR column.
An abbreviated list
of Federal Siqjply
Codes is included in the Appendix.
f. The part number
which uniquely identifies
the item
to the original
manufacturer is listed
in
the
MFR
PART
NO column. If a component must be
ordered
by description, the type number
is listed.
g.
The TOT
QTY column lists the total
quantity
of
the
items used in
the instrument and
reflects the latest
Use
Code, Second
and subsequent
listings of the
same item
are referenced to the
first listing with
the abbreviation
REF. In the
case of optional sub-
assemblies, plug ins, etc. that
are not
always
part
of the instrument,
or
are
deviations from the
basic
instrument
model,
the TOT
QTY column lists the
total
quantity of the item
in
tliat
particular
assembly,
h. Entries
in the REC QTY
column indicate
the recom-
mended number
of spare parts necessary to
support
one to five instruments
for
a period of two
years.
This list
presumes an availability
of common
elec-
tronic
parts at the
maintenance site.
For mainten-
ance for one
year or more at
an isolated side,
it is
recommended that at
least one
of every part in the
instrument
be stocked,
hi the case
of optional sub-
assemblies,
plug ins, etc. that
are not
always
part
of
the
instrument,
or are deviations
from the basic
instrument
model,
the
REC QTY
column lists
the
recommended
quantity
of
the item
in that particular
assembly.
i. The USE
CODE column identifies
certain
parts
which have
been added, deleted
or modified
during
the production
of
the instrument.
Each part for
which
a Use Code
has been assigned
may be iden-
tified
with
a
particular
instrument serial
number
by consulting the
Serial Number Effectivity
List
at the
end of the
parts list.
Sometimes when
a
part is changed, the
new part can
and should
be
used as a replacement
for the original
part. In
this event a parenthetical
note is
added in the
DESCRIPTION
column.
5-1
Page 54
FLUKE
Stock
Number.
5-5.
HOW TO
OBTAIN PARTS
5-6.
Standard
components have
been used
wherever
possible. Standard
components
may be
ordered
directly
from the
manufacturer by using the
manufacturer's part
number,
or
parts
may be ordered
from the
John Fluke
Mfg.
Co. factory or authorized
representative
by using
the
Fluke part number.
In the event
the part you order
has been
replaced by a new
or improved part, the
re-
placement
will be accompanied
by
an
explanatory
note
and installation
instructions, if
necessary.
5-7. You can insure
prompt and efficient
handling
of
your order to the
John Fluke
Mfg. Co. if you include
the following information:
a. Quantity.
b.
c. Description.
d. Reference
Designation.
e.
Instrument
model
and serial number.
Example; 2
each,
4805-177105,
Transistors,
2N3565
Q107-108
for
845AR,
s/n 168.
If you
must
order structural
parts
not listed
in the
parts
list,
describe the
part
as completely
as
possible. A
sketch
of
the
part
showing its
location to
other
parts
of
the instrument
is usually
most helpful.
5-8.
LIST OF ABBREVIATIONS
ac alternating current
mw milliwatt
A1
Aluminum
. na
nanoampere
amp ampere
nsec nanosecond
assy assembly
nv nanovolt
cap
capacitor
a
ohm
car flm carbon film
ppm parts per million
C centigrade
piv peak inverse voltage
cer
ceramic
p-p
peak to peak
comp composition
Pf
picofarad
conn connector
piste plastic
db
decibel
p
pole
dc
direct current
pos
position
dpdt double-pole,
double-throw
P/C
printed circuit
dpst double-pole, single-throw
rf
radio frequency
elect electrolytic
rfi radio frequency interference
F
fahrenheit
res resistor
Ge
germanium
rms root mean square
gmv guaranteed minimum
value
rtry rotary
h henry
sec second
Hz hertz
sect section
hf high frequency
S/N
serial number
IC integrated circuit
Si
silicon
if intermediate frequency
scr silicon
controlled rectifier
k
kilohm
spdt single-pole,
double-throw
kHz kilohertz
spst single-pole, single-throw
kv kilovolt
sw
switch
If low frequency
Ta tantalum
MHz megahertz
tstr transistor
M megohm
tvra transistor voltmeter
met flm metal film
uhf ultra
h^h frequency
ua microampere
vtvm
vacuum tube voltmeter
uf microfarad
var
variable
uh
microhenry
vhf
very high frequency
usee
microsecond
vlf
very low frequency
uv
microvolt
v
volt
ma
milliampere
va
voltampere
mh
millihenry
vac
volts, alternating current
m
milliohras vdc
volts, direct current
msec
millisecond
w
watt
mv
millivolt
ww wire wound
5-2
893A
Page 55
REF INDEX
DESIG NO
Ml
P1,P2
R1
R2
R3
R4
R5
R6
R7
R9
R12
S13,R14
51
52
DESCRIPTION
STOCK
NO
AC/DC
DIFFERENTIAL VOLTMETER
Figure
5-1
893A
Front Panel
Assembly
(See Figure
5-2)
Reference Amplifier
P/C
Assembly
(See
Figure 5-3)
1702-232793
(891A-4001)
Reference Inverter P/C Assembly
(See Figure
5-4)
1702-250175
(893A-4002)
Null Detector
P/C
Assembly
(See
Figure 5-5)
1702-232819
(891A-4003)
Kelvin-Varley
P/C
Assembly
(See
Figure 5-6)
1702-232827
(891A-4004)
AC Converter P/C Assembly
(See Figure 5-7)
1702-250167
(893A-4001)
Rear Panel Assembly
(See
Figure 5-8)
Meter,
100-0-100
ua
2901-236513
Line cord (not illustrated)
6005-226100
Res,
car
flm, 90M
±1%,
2w
4703-192138
Res, car flm, 9M ±0.
5%,
Iw
4703-107557
Res, car flm, 1M±1%, l/2w
4703-107219
Res,
car flm,
90k
±0.5%,
l/2w
4703-107292
Res,
car
flrn, 9k ±0.
5%,
l/2w
4703-107250
Res, car
flm,
900S7 ±0.
5%,
l/2w 4703-107771
Res,
car flm, 100S2
±0.
5%,
l/2-w
4703-107730
Res, comp, Ik
±10%,
Iw
4704-109371
Res, met
flm,
IM,
matched
set
with
A7R37
4705-245597
Res, met flm, 100k
±1%,
l/2w 4705-151316;
Switch, rotary,
RANGE, DCsection
5105-254573
Switch, rotary, POWER S105-242917
Switch, rotary,
NULL
5105-242875
Switch, rotary,
MODE
5105-250555
Switch
wafer,
MODE,
deck
"A”
5105-250530
Coupler, power switch, mode
wafer
Cover, bottom (not
illustrated)
2402-104505
3156-230169
MFR TOT REC
USE
PART
NO
QTY
QTY CODE
1702-232793
1
1702-250175
1
1702-232819 1
1702-232827
1702-250167
75042
89536
89536
89536
89536
89536
89536
89536
2901-236513
2270
MEHT-X
Type
C13
Type C12
Type C12
Type C12
Type
C12
Type
C12
GB1021
4705-245597
TypeCBC-TO
2
5105-254573
5105-242917
5105-242875
1
5105-250555
1
5105-250530 1
2402-104505 2
3156-230169
1
Page 56
REF INDEX
DESIG
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
Cover,
top (not illustrated)
3156-230151
89536
3156-230151
1
Dial,
0-9
2403-232215
89536 2403-232215
2
Dial,
0-10
2403-232207
89536 2403-232207
I
Dial, 0-100
2403-242859
89536
2403-242859
1
Foot, plastic
(not illustrated) 3155-230037
89536
3155-230037
4
Handle
2906-231456
89536 2906-231456
1
Indicator,
ON-OFF flag :
3156-232223
89536
3156-232223
1
Shaft,
power switch
2406-250563
89536 2406-250563
1
Trim
strip, front
(not illustrated)
3154-230771
89536
3154-230771
2
Trim strip,
rear (not
illustrated)
3154-230789
89536
3154-230789
2
Trim strip, side
insert (not
illustrated)
3155-230920
89536
3155-230920
2
Figure
5-1
.
893A AC/DC
DIFFERENTIAL VOLTMETER (Sheet
1 of
2)
2/10/75
893A
Page 57
Figure
5-1
.
893A AC/DC DIFFERENTIAL VOLTMETER
(Sheet
2 of
2)
5-5
8 93 A
Page 58
893ft
:ftC-.OC-DiffERENT!fll
VOl.TMETER
TOT REC
USE
O
QTY
QTY
CODE
STOCK
DESCRIPTIO
Cap,
piste, 0.
047 Ilf
±20%,
1.
2kv
(across
J2 and
J3)
1507-182683
99217
MR473L12 2
Binding post,
red,
HI 2811-226308
58474
DF21RC
Binding
post, red,
LO
2811-226308
58474
DF21RC
Binding
post, black
GROUND 2811-226282
58474
DF21BC
Res, corap,
lOOM
±10%,
l/2w
(across
J2
and
J3)
4704-190520
01121
EB1071
Knob,
Digit
2405-158949
89536 2405-158949
4
Knob,
NULL SENS,
MODE,
RANGE
2405-158956
89536 2405-158956
3
Knob, POWER
2405-235689
89536 2405-235689
Link,
shorting
2811-101220
24655
938L
Panel,
front
Panel,
front
{893A/AC)
1406-244558
89536
1406-244558
1
1406-314734
89536
I
1406-314724
1
Figure
5-2.
FRONT PANEL ASSEMBLY
(893A)
5-6
6/16/72
893A
Page 59
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
A2
REFERENCE AMPLIFIER P/C
ASSEMBLY
-Figure
5-3
NOTE: The Reference
Amplifier
P/C As-
sembly (A2),
the Reference Inverter
P/C
Assembly (A3) and their intermatched
re-
sistor
set
can be ordered
under one part
number, 1702-250209
(893A-4005).
1702-232793
(891A-4001)
89536
1702-232793
REF
Cl F4-R1
Cap,
elect, 400uf
+50/-10%,40v
1502-185868
73445
C437ARG40O 2
C2 D4-P1 Cap,
elect,
400uf
+50/-
10%,
40v
1502-185868
73445
C437ARG400
REF
C3 F4-R1
Cap,
piste, 0. 22uf
±20%,
250v
1507-194803
73445
C280AE/
P220K
2
C4
F2-Q1 Cap,
piste,
0.1uf±20%, 250v
1507-161992
73445
C280AE/
PIOOK
7
C5 F2-P5
Cap, piste, 0. luf
±20%,
250v
1507-161992
73445
C280AE/
PIOOK
REF
C6 C3-S2 Cap,
piste,
0.
22uf
±20%, 250v
1507-194803
73445
C280AE/
P220K
REF
C7 H2-T5 Cap, piste,
0. luf
±20%,
250v
1507-161992
73445
C280AE/
PIOOK
REF
C8
15-Ul
Cap,
piste,0.luf
±20%,
250v
1507-161992
73445
C280AE/
PIOOK
REF
C9
13-P3
Cap,
Ta,
3.
3uf
±10%,
20v
1508-182808
05397
K3R3C20K 1
CRl
13-P3 Diode,
silicon, 150
ma,
6
piv 4802-113308
07910
CD13161 2
1
CR2 E1-P5
Diode, silicon,
150 ma,6piv
4802-113308
07910 CD13161
REF
CR3
01-S2 Diode, zener,
matched
CR4 D3-S3
Diode, zener,
matched
[i>
CR5
CR6
Q1
15-P3
Fl-Sl
H4-R5
Diode, zener,
15v
Diode, silicon,
100maatl.5v
Tstr, silicon,
PNP
4803-246033
4802-261370
4805-229898
07910
22767
04713
IN965A
S1330
MPS6522
1
3
5
1
1
1
B
Q2
I2-R1
Tstr, silicon,
NPN
4805-183004
95303 40250
3 1
Q3
E5-R2 Tstr, silicon,
NPN 4805-220087
03508
12E-1516
1 1
Q4
H2-P1
Tstr, silicon,
NPN
4805-168708
03508
2N3391 11 1
Q5
D2-Q1 Tstr, silicon,
NPN 4805-168708
03508
2N3391
REF
Q6
D1-Q3 Tstr, silicon,
NPN 4805-168708
03508
2N3391
REF
Q7
F5-Q2 Tstr,
silicon,
PNP 4805-203364
07263
2N3638 2 1
Q8
G4-Q1
Tstr, silicon,
NPN 4805-168708
03508
2N3391
REF
Q9
G4-Q5 Tstr, silicon,
NPN
4805-168708
03508
2N3391 REF
5-7
fiQ-^ A
Page 60
Page 61
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
B
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
R1 J1-P3
Res,
coinp,
15k
±5%,
l/4w
4704-148114
01121
CB1535
1
R3 H1-R5 Res,
comp, 2. 7k
±5%,
i/4w
4704-170720
01121
CE2725 1
R4 J4-T3 Res, corap, 62k
±5%,
l/4w
4704-220053
01121
CB6235 1
R5 H5-P3 Res,
corap,
Ik
±5%,
l/4w
4704-148023
01121
CB1025
10
R6 E5-Q3 Res, met flm,
196k
±1%,
-l/2w
4705-161513
75042 Type CEC-
TO
2
R7
F2-Q4 Res,
comp, Ik
±5%,
l/4w
4704-148023
01121 CB1025
REF
R8
H3-P3 Res, comp, 47k
±5%,
l/4w 4704-148163 01121
CB4735 1
R9
12
-P3 Res,
comp,
680k
±5%,
l/4w
4704-188433
01121 CB6845 2
RIO E1-Q5 Res,
comp,
lk±5%,
1/477
4704-148023 01121
CB1025 REF
Rll E4-Q2 Res, met flm,
196k
±
1%,
l/2w
4705-161513
75042 Type CEC-
TO
REF
R12
E2-Q4 Res,
corap, Ik
±5%,
l/4w 4704-148023
01121
CB1025
REF
R13 Gl-Rl Res, comp, IQOk
±5%,
l/4w 4704-148189 01121
CB1045
3
R14
F5-S1
Res,
ww, matched
[i>
R15 H2-Q4 Res,
comp,
3k
±5%,
l/4w
4704-193508
01121 CB3025
1
R16
G2-Q4
Res, met flm,
9fcfcl%, l/2w 4705-159434
75042 Type
CEC-
TO
1
R17 F3-R5
Fles, ww, 4k
±0.03%,
Iw 4707-131672
89536 4707-131672
1
R18 G1-R5
Res,
ww,
10k
±0.05%, Iw
4707-131664
89536 4707-131664
1
R19 E3-T4
Res,var, ww, 3k
±10%,
l-l/4w 4702-112458
71450 Type no
1
R20 H3-Q4
Res, met flm, 60. 4k
±1%,
i/2w 4705-161067 75042
Type CEC-
TO
1
R21 D4-S2 Res,
ww, 12. 525k, matched
j
R22
E4-S2 Res, ww, 12.
525k, matched
[i>
R23 C5-S2
Res,
met
flm, 499k
±1%,
l/2w 4705-151332
75042
Type CEC-
TO
2
R24 D4-Q2
Res, met flm,
34k
±1%,
l/2w 4705-151241
75042 Type CEC-
TO
1
R25
C1-R3 Res, comp, 22k±5%,
l/4w 4704-148130 01121
CB2235 2
R26 C2-T5
Res, var, ww,
lk±20%,
l-l/4w 4702-111575
71450
Type 110 2
R27 E2-S3
Res,ww, matched
5
>-
R28 C3-Q3
Res,
met
flm, 95. 3S7±1%,
l/2w
4705-155127
75042
Type CEC-
TO
1
R29 B5-Q3
Res, met flm, 47, 5Q±
1%,
l/2w
4705-151290
75042
Type CEC-
TO
1
5-9
893A
Page 62
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE!
R30
B5-R5
Res,
met flm
52.
30
± 1
%,
l/2w 4705-155069
75042
Type
CEC-
1
TO
R31
E1-R4
Res, ww,
49.
488k ±0.
05%,
Iw
4707-163444
89536
4707-163444
1
1
R32
G3-S2
Res,
ww,
matched
[l>
R33 G3-T3
Res, var,
ww, 25fi
±10%,
l-l/4w
4702-161703
71450
Type 110
2
1
R34
H1-S5
Res,
ww,
49.
488k, matched
R35 I3-T4
Res, var, ww,
25S7±
10%,
l-l/4w
4702-161703
71450
Type
110
REF
1
R36
G4-S2 Res, ww,
5.48ik, matched
[I>>
R37 F1-R5
Res, comp,
Ik
±5%,
l/4w 4704-148023
01121
CB1025
REF
D
1
[Tl> CR3, CR4,
R14, R27 & R32 are a factory
matched
set and
must be
replaced
as an entire
set. For
replacement,
order
Zener-Resistor
Set, part
number 4807-219303.
A2R21, A2R22/A3R12,
A3R13,
A3R15
& A3R16 are factory
matched
for
tolerance
and
temperature coefficient.
Individual
resistors can
be
replaced by giving
model,
serial number,
full reference
designation
and
all information
stamped
on the
resistor.
R34
& R36
are
factory
matched and
must be replaced
as a
set. For
replacement,
order
Reference Divider
Resistor
Set, part
number
4710-219295.
5-10
893A
Page 63
REF
INDEX
DESCRIPTION
STOCK
ill
MFR
TOT
REC USE
DESIG
NO
NO
PART
NO
QTY QTY CODE
A3
REFERENCE
INVERTER
P/C ASSEMBLY
1702-250175 89536
1702-250175
REF
Figure
5-4
(893A-4002)
Note: The
Reference Amplifier P/C As-
sembly
(A2), the Reference
Inverter P/C
Assembly (A3) and their intermatched re-
sistor set
can be ordered under one part
number, 1702-250209
(893A-4005).
Cl
F4-S4 Cap, elect, 400 uf +50/-
10%,
25v
1502-168153 73445 C437ARF400
2 1
C2 H4-Q1
Cap, elect,
400 uf +50/-l0%, 25v
1502-168153 73445 C437ARF400 REF
C3
E4-T3 Cap,
piste, 0. 1 uf
±20%,
250v
1507-161992 73445 C28(AE/PKXK REF
C4 G4-R3
Cap,
elect, 5uf+50/-10%, 64v
1502-218966 73445 C426ARH5 2
m
C5
G4-R2
Cap, elect, 5 uf +50/-10%, 64v
1502-218966 73445 C426ARH5 REF
C6
G2-S4 Cap,
piste,
1
uf
±20%,
250v
1507-190330 73445 C280AE/P1M
1
C7
G1-Q4
Cap, piste, 0.47uf±20%, 600v
1507-105494 72928 363-114M 2
C8 Gl-Pl
Cap,
piste, 0.47 uf±20%,
600v
1507-105494 72928
363-114M REF
C9
13
-P5 Cap,
piste, 0.047 uf±20%, 1. 2 kv
1507-182683 99217 MR473L12 REF
CIO
B5-T2
Cap,
Ta, 68uf±10%, I5v
1508-182824
05397 K68C15K
2
cn
B5-T4
Cap,
Ta,
68
uf
±10%,
15v
1508-182824 05397 K68C15K REF
C12 B5-N5
Cap,
cer, 0.05
uf+80/'20%,
500v
1501-105676
56289
33C58 1 H
CRl
E3-T3
Diode, germanium, 80
ma,
100
piv
4802-149187 49956 1N270
5
1
CR2 F3-R3
Diode,
silicon,
1
amp,
100
piv
4802-116111 05277 1N4817 6
1
CR3 F3-R2
Diode, silicon, lamp,
100
piv
4802-116111 05277 1N4817 REF
CR4 F3-Q1
Diode, silicon,
1
amp,
600
piv
4802-112383 05277 1N4822
4
1
CR5
G3-Q1
Diode,
silicon, lamp,
600
piv
4802-112383
05277
1N4822 REF
CR6
F3-P5
Diode,
silicon, lamp,
600
piv
4802-112383 05277 1N4822
REF
CR7
G3-P5
Diode, silicon, lamp,
600
piv
4802-112383 05277 1N4822
REF
CR8
C3-T5 Diode,
germanium, 80 ma,
100
piv
4802-149187 49956 1N270
REF
CR9
B4-T1
Diode, germanium,
80 ma,
100 piv
4802-149187 49956 1N270
REF
LI G4-S1
Choke,
470 uh, 180 ma
1801-14782?
72259 WEE-470 1
C
LI E5-T3
Choke, 47 uh,
420
ma
1801-147850
72259 WEE-47 2
D
L2 C3-T2
Choke,
47 uh, 420 ma
1801-147850 72259 WEE-47
REF D
LI
E5-T3
Choke, RF, 75 uh, iOmfi
1804-286427 89536
1804-286427 2
G
L2
C3-T2
Choke,
RF,
75 uh, I0mI2
1804-286427 89536
1804-286427 REF G
Q1
E2-S3
Tstr,
silicon, NPN
4805-183004 95303
40250
FIEF
Q2
C5-S3
Tstr, silicon,
NPN
4805-183004 95303 40250 REF
R1 H2-R4
Res, comp, 2S7
±5%,
l/2w
4704-218735 01121 EB20G5 1
R2
G4-S1
Re^ comp, 10k
±5%,
l/4w
4704-148106 01121 CB1035 6
R3
E1-T4 Res,
comp, 33J2
±5%,
l/4w
4704-175034
01121 CB3305
2
9/22/71
5-11
ass A
Page 64
i2l3l4l5tll2i3l4|5ill2|3i4i5lll2i3l4l5lli2l3i4i5ll!2i3l4l5(ll2l3l4l5lli2l3l4!5lli2i3l4[5|l|2|3|4|5lll2|3}4|
5-12
Figure
5-4.
REFERENCE INVERTER
P/C ASSEMBLY
893A
Page 65
REF
DESIG
INDEX
NO
DESCRIPTION
R4
E2-T2
Res,
comp,
33fi
±5%,
i/4w
R5
D2-T4
Res,
var, ww,
Ik
±20%,
l-l/4w
R6
H1-R5 Res, comp, 100S2
±5%,
l/4w
R7
H2-S4
Res,
comp, 5.
lk±5%,
l/4w
R8 H2-T3 Res, var, ww, 6k
±5%,
l-l/4w
R9 J1-Q4 Res,
comp, 5.
6M
±10%,
l/2w
RIO
J2-Q4
Res, comp,
5.
6M±10%,
l/2w
RU
J3-Q4 Res,
comp, 5.
6M±10%,
l/2w
R12 H5-S3
Res, ww,
IM, matched
R13
I5-S2
Res, ww,
IM,
matched
R14 J1-T5 Res,
var,
ww, 100S2
±20%,
l-l/4w
R15
J3-S3
Res,
ww, 98.
582k,
matched
R16
K1-S3
Res, ww, 98. 582k, matched
R17
F1-T2
Res,
comp,
470D
±5%,
l/4w
R18
C4-T2
Res,
corap,
470D
±5%,
l/4w
R19
D1-N5
Res,
comp, lOOD
±5%,
l/4w
T1
D3-Q5 Transformer,
toroid
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
4704-175034
01121 CB3305
REF
4702-111575 71450
Type 110
REF
4704-147926
01121 CB1015 4
4704-193342 01121
CB5125
1
4702-113209
71450
Type
110 2
4704-178558
01121 EB5651 3
4704-178558
01121 EB5651
REF
4704-178558 01121
EB5651 REF
[E>
4702-112797 71450
Type
110
1
4704-147983 01121 CB4715
5
4704-147983 01121
CB4715
REF
4704-147926 01121
CB1015 REF
5602-250415
89536
5602-250415
1
[|>
A2R21, A2R22/A3R12, A3R13,
A3R15
&
A3R16 are factory matched
for
tolerance and temperature
coefficient. Individual resistors
can
be
replaced by giving model, serial number, full reference designation
and all information
stamped
on the
resistor.
89.3A
Page 66
I|2i3|4i5|ll2[3l4i5|li2i3l4l5{ll2l3l4l5lll2l3{4l5ili2i3i4i5ill2i3ui5lll2|3l4!5lll2|3l4i5lll2l3l4l5lll2i3l4l5
Figure 5-5.
NULL DETECTOR
P/C ASSEMBLY
Page 67
893A
REF
OESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
A4
NULL DETECTOR P/C
ASSEMBLY
Figure
5-5
1702-232819
(891A-4003)
89536 1702-232819
REF
Cl
G1-Q5 Cap,
piste, 0. luf
±20%,
120v
1507-167460
99217
Type SEC 2
C2
G4-Q5
Cap, piste,
0. luf
±20%,
I20v 1507-167460
99217
Type SEC
REF
C3
I2-R5
Cap,
piste, 0.
047uf
±
10%,
80v
1507-195099
56289
192P4739R8 2
C4
H4-S5 Cap, cer,
3pf
±10%,
500v 1501-226316
00656
Type Cl-1
1
C5
G5-T1 Cap, piste,
0. luf
±20%,
250v
1507-161992
73445
C280AE/
PIOOK
REF
C6
J1-Q4
Cap, eleet,
50uf
+50/-10%,
25v
1502-168823
73445
C426ARF50 4
1
C7
H3-Q3 Cap,
piste, 0. 0047uf
±20%,
200v
1507-106054
56289
192P47202
1
C8
J1-S2
Cap,
piste, 0.
Oluf
±10%,
200v 1507-168450
14655 DMF2S1
1
C9 K1-Q5 Cap,
elect, 50uf
+5O/“10%, 25v 1502-168823
73445
C426ARF50
REF
CIO
I3-Q3 Cap,
mica,
2,200pf±5%,
500v
1504-148346
14655 CD19F222J
1
Cll
J4-Q5
Cap,
elect, 50uf
+50/-10%,
25v
1502-168823
73445
C426ARP50
REF
C12 E1-Q5
Cap, elect,
lOui
+50/-10%, 25v
1502-170266
73445 C426ARF10
1
H
C13
E3-Q5
Cap,
elect, 400uf
+50/-10%, 4v
1502-187773
73445
C426ARB400
1
II
C14 C2-S2
Cap, piste,
0. 022uf
±5%,
200v
1507-233973
56289
192P22352
2
C15
C3-S2
Cap, piste,
0.022uf
±5%,
200v
1507-233973 56289
192P22352
REF
C16
D1-P3 Cap, piste,
0. luf
±
20%,
250v 1507-161992
73445
C280AE/
PIOOK
REF
E
C17
B5-P3 Cap, piste,
0. luf
±20%,
250v 1507-161992
73445
C280AE/
PIOOK
REF
E
C18
D3-P3
Cap, elect,
125uf
+50/-10%, l6v 1502-186296
73445 C426ARE125
2
1
C19
C2-P3
Cap, elect,
125uf
±50/-l0%, I6v 1502-186296
73445
C426ARE125 REF
C20 F1-S4
Cap,
elect, 80uf
±50/-10%, 16v
1502-192914
73445 C426ARE80
1 1
cm
F4-S3
Diode, silicon,
treated
4802-180885
89536 4802-180885
2
1
CR2
F4-S2
Diode, silicon,
treated
4802-180885
89536 4802-180885
REF
CR3
C5-P3 Diode,
germanium,
80ma,
100
piv 4802-149187
49956
IN270
REF
CR4 B4-P2
Diode, germanium,
80ma,
100
piv
4802-149187
49956
IN270 REF
Q1
H4-R5
Tstr, MOS,
P-channel 4805-226043
07263
FT704
1
1
Q2
I1-Q4
Tstr, silicon,
NPN
4805-242065
04713
2N5089 2
1
Q3
I3-P3
Tstr, silicon,
NPN 4805-242065
04713
2N5089
REF
Q4
H5-P2 Tstr, silicon,
NPN
4805-168708
03508
2N3391 REF
5-15
Page 68
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
MFR
MFR TOT
QTY
REC
USE
NO PART
NO QTY CODE
Q5 G3-P2
Tstr,
silicon,
PNP 4805-229898
04713 MPS6522
REF
Q6
F4-P2
Tstr, germanium,
NPN 4805-117127
01295
2N1304
1 1
Q7
F1-P2
Tstr, germanium,
PNP 4805-190298
95303
2N1305
1 1
Q8
D5-S2 Tstr, germanium,
NPN
4805-182691
01295
GA3937
1
1
Q9
C5-R2
Tsrt, silicon,
NPN 4805-168708
03508
2N3391
REF
QIO B4-RI Tstr, silicon,
NPN
4805-168708
03508
2N3391
REF
Qll
D2-S5
Tstr, silicon,
NPN 4805-168708
03508
2N3391
REF
R1
G1-S5
Res,
comp, 470k
±10%,
2w 4704-110247
01121
HB4741
1
R2 G3-S1 Res, comp, 470k
±5%,
l/4w 4704-188441
01121
CB4745
1
R3
H3-S2 Res, carflm,
330k
±1%,
l/2w 4703-107359
75042
Type
C12
1
R4 G2-T1 Res,
comp,
56G±5%,l/4w
4704-147900
01121
CB5605 1
R5
H3-T4
Res,
var, ww, 500n
±10%,
l~l/4w 4702-112433
71450
Type 110
1
R6
H2-R1
Res, car Elm, lOfi
±1%,
l/2w
4703-107789
75042
Type
Cl 2 1
R7 H1-S4 Res, comp, lOM
±5%,
l/4w 4704-194944
01121
CB1065
1
R8 H5-R1 Res, comp, 3. 3M
±10%,
l/2w 4704-108282
01121
EB3351
1
R9 H5-Q2 Res, comp, 1. 5M
±5%,
l/4w
4704-182857
01121
CB1555
1
RIO J4-S2 Res, met Elm, 169J2
±1%,
l/2w 4705-151183
75042
Type
CEC-
TO
2
Rll
K2-S1 Res, comp, 680k
±5%,
l/4w
4704-188433
01121
CB6845
REF
R12 I1-Q2 Res, comp,
IM
±5%,
l/4w 4704-182204
01121
CB1055
1
R13
I5-Q2
Res, comp, 27k
±5%,
l/4w 4704-148148
01121
CB2735 2
R14 H1-P3 Res,
comp,
10k
±5%,
l/4w 4704-148106
01121
CB1035 REF
R15 I5-S2 Res, met
flm,
80.6k±
1%,
l/2w 4705-150680
75042
Type CEC-
TO
1
R16 J3-S2 Res,
met flm, I69f7
±1%,
l/2w 4705-151183
75042
Type
CEC-
TO
REF
R17 J3-T4
Res,
var, ww,
10k
±20%,
l-l/4w
4702-112862 71450
Type 110
7
R18 K1-S2
Res,
met flm,
10k
±1%,
l/2w 4705-151274
75042
Type
CEC-
TO
1
R19 E4-F3 Res, comp, 27k
±5%,
l/4w 4704-148148
01121
CB2735 REF
R20 E2-P2
Res,
corap,
Ik
±5%,
l/4w 4704-148023
01121
CB1025
REF
R21 E1-R5 Res,
.comp, Ik
±5%,
l/4w 4704-148023
01121
CB1025
REF
R22 E4-33 Res,
met flm, 2.55k±l%, l/2w
4705-176362
75042
Type CEC-
TO
2
5-16
6/16/72
893A
Page 69
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART NO
TOT
QTY
REC
QTY
USE
CODE
R23 D4-R2
Res,
comp,
39k
±5%,
l/4w
4704-188466
01121
CB3935
1
R24 C2-Q5 Res, met flm,
383k
±1%,
l/2w 4705-176388
75042
Type
CEC-
TO
1
R25 C3-Q5 Res, met flm,
499k
±1%,
l/2w
4705-151332
75042
Type CEC-
TO
REF
R26
B4-T1
Res, comp, 10k
±5%,
1/4W
4704-148106 01121
CB1035
REF
R27
C2-T4 Res, var, ww,
10k
±20%,
l~l/4w 4702-112862
71450
Type 110
REF
R28
B5-T1 Res, comp,
10k
±5%,,^ 1/4W 4704-148106
01121
CB1035
REF
R29
D1-S2
Res, met flm,
309fi
±1%,,
l/2w 4705-172130
75042
Type CEC-
TO
1
R30 D4-T1
Res, met flm, 2.
55k
±1%,
l/2w 4705-176362
75042
Type
CEC-
TO
REF
R31 E1-T4
Res,
var,
ww, 10k
±20%,
l-l/4w 4702-112862
71450
Type
110
REF
R32
Fl-Qi
Res, car
flm, 10k
±1%,
l/2w
4703-107128
75042
Type
C12 1
R33 Dl-Ql
Res,
cornp,
llOD
±5%,
l/4w
4704-193474
01121
CB1U5
2
E
R34 B5-Q1 Res, cornp, HOD
±5%,
l/4w
4704-193474
01121
CBU15 REF E
R35
Hl-Pl Res, corap,
100k
±5%,
l/4w
4704-148189
01121
CB1045
REF
Shield
( not illustrated)
3156-232082
89536
3X56-232082
1
5-17
RCiSA
Page 70
Figure 5-6.
KELViN-VARLEY P/C ASSEMBLY
5-18
893A
Page 71
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
A5
KEIVIN-VARLEY
P/C
ASSEMBLY
1702-S 32827 89536
1702-232827
REF
Figure
5-6
(891A
-4004)
Cl G1-R4
Cap, piste, luf
±20%,
200v
1507-1
06450 84411
Type
X663F
1
C2 F3-R5
Cap,
piste, lui
±20%,
120v
1507-1
93748
84411
JF-11 1
R1 G3-S4
Res, ww,
100k
H2 G4-S4 Res, ww, 100k
R3 H1-S4 Res,
ww,
100k
R4 H3-S4 Res,
ww,
100k
R5 H4-S4 Res,
ww,
100k
R6 Ii-S4 Res,
ww, 100k
R7
I3-S4 Res, ww, 100k
R8 I4-S5
Res,
ww,
100k
R9 I5-S5 Res,
ww,
100k
RIO
J2-S5
Res, ww, 100k
RU J4-S4 Res,
ww, 100k
R12 K1-S4
Res, ww, 100k
R13
G2-R1 Res,
ww,
20k
R14
H3-Q3
Res, ww, 20k
R15 H4-Q3 Res,
ww, 20k
R16
H5-Q3 Res,
ww, 20k
R17 H5-Q4 Res,
ww, 20k
R18
I3-Q3 Res,
ww, 20k
R19
I5-Q3 Res,
ww,
20k
R20 J2-Q3
Res,
ww,
20k
R21
J3-Q3 Res, ww, 20k
R22
J5-Q3 Res,
ww,
20k
R23 J5-Q4
Res, ww, 20k
R24
G5-P2 Res,
ww,
4k
R25
H1-P2 Res,
ww, 4k
R26 H3-P2
Res, ww, 4k
'
R27
H5-P2 Res,
ww, 4k
E>
893A
Page 72
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
R28 I1-P2 Res, ww,
4k
E>
R29 Il-Pl
Res,
ww,
4k
1 .
R30
I4-P2
Res,
ww,
4k
R31 I5-P2
Res, ww,
4k
R32 Jl-Pl
Res, ww, 4k
R33 J1-N5
Res,
ww,
4k
R34
J4-P1
Res, ww,
4k
R35
F4-P5
Res, met llm,
34k
.+
1%,
l/2w 4705-
151241
75042
Type CEC-
REF
E
R35
F4-P5 Res,
met flm, 34. 8k il%, l/2w 4705-236711
75042
TO
TypeCEC-TO 1
F
R36
G2-P5
Res, var, ww,
iOk
±20%,
i-l/4w
4702-
112862
71450
Type no
REF
R37 E1-N3
Res, var, ww,
10k
±5%
4702-
232868
89536
4702-232868
1
O
R37 EI-N3
Res,
var,
ww, 10k
±5%
4702-
338368
89536
4702-338368
P
S6 D4-U2
Switch,
rotary,
KV Dial
"A”
5105-
242891
89536 5105-242891
1
S7
D4-S2 Switch,
rotary,
KV Dial
"8”
5105-
242909
89536 5105-242909
2
S8
D4-Q4
Switch,
rotary,
KV
Dial
"C”
5105-
242909
89536
5105-242909
REF
Cover (not illustrated)
3156-
235697
89536 3156-235697
1
[5>
RI
through R34 are factory matched
for tolerance
and
temperature
coefficient. Individual resistors
can
be replaced by
giving model,
serial number, full
reference designation
and all
information
stamped
on the resistor.
5-20 6/16/72
893A
Page 73
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
A
7
AC CONVERTER P/C
ASSEMBLY
Figure
5-7
1702-250167
(893A-4001)
89536 1702-250167
REF
Cl
H1-Q3
Cap, piste,
0. 22uf
±20%,
1200v 1507-220079
84411
JF-17
1
C2 F3-P2 Cap,
piste, 0. luf
±20%,
250v 1507-161992
73445
C280AE/
PIOOK
REF
C3 J2-Q2
Cap, elect,
200uf
±50/-10%, lOv 1502-236935
73445
C426ARD200
2
1
C4
I2-N5 Cap,
Ta,
lOuf
±20%,
15v 1508-193623
56289
196D106X-
0015
1
C5 H1-P4
Cap, piste,
0. 047uf±10%,
80v
1507-195099
56289
192P4739R8 REF
C6 G3-P4
Cap, eer,
7. 5pf
±10%,
500v 1501-159939
00656
Type
Cl-1 2
C7 I3-U5
Cap, mica,
lOOpf
±5%,
500v 1504-148494
14655
CD15F101J
1
C8 D4-P1
Cap,
Ta, 15uf
±10%,
20v 1508-153056
05397
K15C20K
1
C9 C3-F1 Cap,
mica, 220pf
±5%,
500v 1504-170423
14655
Cm5F221J
2
CIO D2-N1
Cap, mica,
10pf±10%, 500v
1504-175216
14655
CD15C0100K 1
Cil
C3-N1
Cap, Ta,
39uf
±20%,
6v
1508-163915
56289
196D396X0006
1
C12 B4-M4
Cap, elect,
200uf
+50/-10%, lOv 1502-236935
73445
C426ARD200
REF
C13
C1-R4
Cap, piste,
5uf
±20%,
60v 1507-160952
72928
364W-505M
2
1
C14 CI-S3
Cap,
piste, 5uf
±20%,
60v 1507-160952
72928
364W-505M
REF
C15 C1-P4
Cap,
var, 9-35pf,
200v 1509-153080
72982 538-002
1
C16
E3-M5
Cap, elect,
50uf
±50/-10%,
25v
1502-168823
73445
C426ARF50
REF
C17 F3-M4
Cap,
mica, SOOOpf
±5%,
500v 1504-161786
14655
CD19F302J
1
C18
I2-V1 Cap,
mica,
820pf
±5%,
500v
1504-148395
14655
CD19F821J
1
C19
Cap,
mica,
150pf
±5%,
500v
(below
C20)
1504-148478
14655
CDISFISIJ
1
C20
E4-R2
Cap, cer,
7. 5pf
±10%,
500v 1501-159939
00656
Type Cl-l
REF
C21 D2-Q4
Cap,
var, 0.
8-lOpf,
250v 1509-193912
91293
JMC2950 2
C22 E3-Q4
Cap, var, 0.
8-lOpf,
250v 1509-193912
91293
JMC2950
REF
C23 H2-P2
Cap,
Ta, 22uf
±10%.
15v 1508-182816
05397
K22C15K 2
C24
H2-M5 Cap, Ta,
22uf
±10%,,
15v 1508-182816
05397
K22C15K
REF
C25 I3-U1
Cap, mica,
220pf
±5%,
500v
1504-170423
14655
CD15F221J
REF
cm
F4-Q1 Diode,
silicon, lOOrna
at
1. 5v 4802-261370
22767
S1330 REF
CR2 F5-Q1
Diode,
silicon,
lOOmaatl.Sv 4802-261370
22767
S1330
REF
CR3
B2-P3 Diode,
silicon,
2rna at
Iv
4802-161810
03877
SG5658
2
1
5-21
893A
Page 74
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
CR4
B3-1P4 Diode, silicon, 2ma, at
Iv 4802-161810
03877
SG5658
REF
CR5
C4-P2 Diode, zener,
iOv 4803-246611
07910
1N961B
2
1
CRB
H2-N1 Diode, zener,
iOv
4803-246611
07910
1N961B
REF
QI F4-Q5 Tstr,
silicon, FET, N-channel 4805-246066
17856
FN1215
1 1
Q2 F5-P3 Tstr, silicon,
PNP 4805-229898
04713
MPS6522
REF
Q3
F5-F2
Tstr, silicon,
NPN
4805-168708
03508
2N3391
REF
Q4
D3-N4
Tstr, silicon,
PNP 4805-229898
04713
MS
65 2 2
REF
Q5
D3-N2
Tstr, silicon,
PNP 4805-229898 04713
MFS6522
REF
Q6
Cl-Nl Tstr,
silicon, NPN 4805-218081
04713
MPS6520
3
1
Q7 C4-M5 Tstr, silicon,
NPN 4805-218081
04713
MFS6520
REF
Q8
B4-N2
Tstr,
silicon, NPN 4805-218081
04713
MFS6520 REF
Q9 E4-N3 Tstr,
silicon, PNP 4805-203364
07263
2N3638
REF
QIO
D5-N1
Tstr,
silicon,
NPN
4805-168708
03508
2N3391 REF
R2
E5-P2
Res,
met flm,
3. 16k
±1%,
l/8w 4705-235291
75042
TypeCEA-TO
1
I
P2
E5-P2
Res,
met
flm, 6. 34k
±1%,
l/8w
4705-267344 75042
TypeCEA-TO 1
J
R3 I3-P1
Res, met flm, 200S7±1%,
l/Sw
4705-245340
75042
Type
CEA-
TO
1
R4 I5-N5
Res,
var,
comp, 5k
±20%,
3/4w 4713-159905
73138
Type
78P
1
R6 n-N2
Res,
met flm, 100ST±1%, l/8w 4705-168195
75042
Type
CEA-
TO
1
R6 H2-N2
Res,
met flm, 4.
99k
±1%,
l/8w
4705-168252
75042
TypeCEA-TO
1
I
R6
H2-N2
Fes, met
flm, 7. 55k
±1%,
l/8w
4705-223529
75042 Type CEA-TO 1
J
R7 F3-N5
Res, met flm, 12. Ik.
±1%,
l/8w 4705-234997
75042 Type
CEA-
TO
1
R8 G5-F1
Res,
met flm, 52.
3k
±1%,
l/8w
4705-237248
75042
Type CEA-
TO
3
R9
G4-P3 Res, met flm,
Ik
±1%,
l/8w 4705-168229
75042
Type CEA-
TO
1
RIO
E4-P1
Res,
comp,
Ik
±5%,
l/4w 4704-148023
01121
CB1025
REF
Rll Jl-Vl
Res, comp, 470fi±5%, l/4w 4704-147983
01121
CB4715 REF
R12 E2-N4
Res, comp, iOk
±5%,
l/4w 4704-148106
01121
CB1035
REF
R13 D3-N5
Res, comp, 100S2
±5%,
l/4w
4704-147926
01121
CB1015
REF
R14 C5-N4
Res,
met flm, 45.
3k
+1%,
l/8w 4705-234971
75042
Type
CEA-
TO
1
R15 E3-N4 Res, met flm, 21. 5k
±1%,
l/8w
4705-168278
75042
Type
CEA-
TO
1
5-22
6/16/72
893A
Page 75
09.5A
REF INDEX
DEStG
1
NO
R16
’
Dl-Nl
R17
:
C3-N2
R18 C2-N1
R19
C2-N3
R20 C5-M5
R21 B2-Q5
R22
B4-Q5
R23
B2-Q3
R24 B4-Q3
R25 B5-N2
R26
B4-N5
R27 C3-Q4
:
R28 G3-N2
R29 F5-N2
R30 jD4-P2
R31
C4-P5
R32 D5-Q5
R33 D4-P5
R34
R34
F1-Q4
F1-Q4
R35 E4-P5
R36 B3-N2
R37
E5-R4
R38 I3-U3
R39 C5-R1
R40 E5-N2
R41 C5-P2
DESCRIPTION
STOCK
NO
Res,
comp, lk±5%, l/4w
4704-148023
Res, metflm, 32.
4k
±1%,
l/8w
4705-182956
Res, comp, Ik
±5%,
l/4w
4704-148023
Res, met flm, I21k±l%,
l/8w 4705-229369
Res, comp,
2000±5%, l/4w 4704-147959
Res, metflm,
52.3k
±1%,
l/8w 4705-237248
Res, met flm, 52.
3k
±1%,
i/8w 4705-237248
Res,
ww,
556R ±0.
1%,
l/4w
4707-249292
Res,
ww,
55647 ±0.
1%,
i/4w
i
4707-249292
Res, comp, 2.
2k
±5%,
l/4w 4704-148049
Res, comp,
22k
±5%,
l/4w
4704-148130
Res,
ww,
12542
±0.1%,
l/4w
4707-249284
Res,
metflm,
4.22k
±1%,
l/8w
4705-168245
Res, var, ww,
6k
±5%,
l-l/4w
4702-113209
Res,
metflm,
8.45k±l%, l/8w
4705-221671
Res,
var, ww,
10k
±20%,
l-l/4w
4702-112862
Res,
metflm,
8.45k
±1%,
l/8w
4705-221671
Res, var, ww,
10k
±20%,
l-l/4w 4702-112862
Res,
met
flm, 7.5k±l%,
l/8w
Res,
metflm, 6. 04k±i%, l/8w
4705-223529
4705-285189
Res, var,
ww,
10k
±20%,
l-l/4w 4702-112862
Res, comp,
lOk
±5%,
l/4w
4704-148106
Res, met
flm,
243k, matched set
with
chassis
mounted
R12
in
Figure
5-1
4705-245597
Res, ww,
24.22k
±0.1%^
l/2w 4707-249326
Res, ww, 2. Silk
±0.1%,
l/2w
4707-249318
Res,
ww,
119.142 ±0.
1
%,
l/4w 4707-249300
Res,cnrnp,
470R,
±5%,
l/4w 4704-147983
MFR
MFR
PART
NO
TOT
QTY
01121
CB1025
REF
75042
Type CEA
-
TO
1
01121
CB1025
REF
75042
Type CEA
-
TO
1
01121
CB2215 1
75042
Type CEA-
TO
REF
75042
Type
CEA-
TO
REF
89536 4707-249292
2
89536
4707-249292
REF
01121
CB2225
2
01121
CB2235
REF
89536 4707-249284
1
75042
Type CEA-
TO
1
71450
Type 110
REF
75042
Type
CEA-
TO
2
71450
Type 110
REF
75042
Type
CEA-
TO
REF
71450
Type 110
REF
75042
TypeCEA-TO
1
75042
TypeCEA-TO
1
71450
Type
110
REF
01121
CB1035
REF
89536
4705-245597
REF
89536 4707-249326
1
89536 4707-249318
1
89536 4707-249300
1
01121
CB4715 REF
6/16/72
5-23
Page 76
REF
DESIG
INDEX
NO
DESCRiPTlON
STOCK
NO
MFR
MFR
PART NO
TOT
QTY
REC
QTY
USE
CODE
R42 E3-N1
Res, comp,
470J^
±5%,
l/4w
4704-147983 01121
CB4715
REF
R43 C5-N5 Res,
comp,
270S2
±5%,
l/Av]
4704-160804 01121
CB2715 1
R44 J1-U3
Res, comp,
lOOR
±5%,
l/4w
4704-147926 01121
CB1015 REF
R45 D2-M4
Res, comp, 330k
±5%,
l/4w
4704-192948 01121
CB3345
1
R46
D5-N2 Res,
comp, 8. 2k
±5%,
l/4w
4704-160796 01121
CB8225 1
R47 E2-P1
Res, comp,
2. 2k
±5%,
l/4w
4704-148049
01121
CB2225
REF
R48 B5-P1
Res, comp,
100k
±5%,
l/4w
4704-148189 01121
CB1045 REF
R49 I3-V2
Res, comp,
430S2
±5%,
l/4w
4704-203869 01121
CB4315
1
39 Gl-Sl
Switch, rotary, RANGE, AC
Section
5105-246710 89536
5105-246710
1
H4-S1 Coupler,
range
switch
3153-248625 89536 3153-248625
1
5-24
893A
Page 77
ll2i3l4|5Ul2l3i4i5{l|2|3i4i5lll2l3!4i5lli2i3!4S5hl2l3!4l5ili2i3l4l5lli2l3l4|5lli2l3i4|5Ui2|3!4l5il|2l3Ul5ll|2|3|4i5
iHf
T
1»-<T
I
Page 78
05277
IN4817
05277
IN4817
05277
IN4817
05277
IN4817
71400 Type
MDL
71400
Type MDL
AC3G
75915 342004
89536 1406-231928
5-26
REF
INDEX
DESIG NO
DESCRIPTION
STOCK
NO
REAR PANEL ASSEMBLY (893A)
Figure
5-8
Diode, silicon,
1
amp, 100
piv
4802-116111
Diode, silicon,
1
amp,
100
piv 4802-116111
Diode,
silicon, 1
amp,
100
piv
(not illustrated)
4802-116111
Diode, silicon,
1
amp,
100
piv
(not illustrated)
4802-116U1
Fuse, slow blow,
1/8
amp,
250v
(for 115v operation)
(not
illustrated)
5101-166488
Fuse, slow blow, l/l6 amp,
250v
(for
230v operation)
(not illustrated)
5101-163030
Connector, male,
3
contact
2109-222612
Switch,
slide
5106-226274
Transformer,
power
5602-223990
Holder, fuse 2102-160846
Panel,
rear
1
1406-231928
MFR TOT REC
USE
PART
NO
QTY
QTY
CODE
Figure
5-8.
REAR PANEL ASSEMBLY
(893A)
893A
Page 79
O»0A
REF
DESIG
INDEX
NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
TOT
QTY
REC
QTY
USE
CODE
AC/DC DIFFERENTIAL
VOLTMETER
Figure
5-9
893AR
1
AI
Front Panel
Assembly
(
See
Figure
5-10)
1
1
A2
Reference
Amplifier
P/C
Assembly
(See Figure
5-3)
1702-232793
(891A-4001)
89536
1702-232793
1
A3
Reference
Inverter
P/C Assembly
(See Figure
5-4)
1702-250175
(893A-4002)
89536
1702-250175
1
A4
Null Detector
P/C Assembly
(See Figure 5-5)
1702-232819
(891A-4003)
89536
1702-232819
1
A5
Kelvin-Varley
P/C Assembly
(See Figure 5-6)
1702-232827
(891A-4004)
89536 1702-232827
1
A7
AC
Converter
P/C
Assembly
(See
Figure 5-7)
1702-250167
(893A-4001)
89536
1702-250167
1
A8
Rear
Panel
Assembly
(see
Figure
5-11)
Ml
Meter,
lOO-O-lOOua
2901-236513
89536
2901-236513
1
PI, P2
Line
cord
6005-226100
91934
2270
1
R1
Res, car flm,
90M ±
1
%,
2w
4703-192138
75042
MEHT-X
1
R2
Res, car
flm,
9M ±0.
5%,
Iw 4703-107557
75042
Type
C13
m
R3
Res, car flm,
IM
±1%,
l/2w
4703-107219
75042
Type C12
I
R4
Res, car
flm,
90k ±0.
5%,
l/2w 4703-107292
75042
Type
C12
R5
Res, car flm,
9k ±0.
5%,
l/2w
4703-107250
75042
Type C12
1
R6
Res, car
flm, 900R
±0.
5%,
l/2w 4703-107771
75042
Type
C12
1
R7
Res, car
flm, lOOR
±0.
5%,
l/2w 4703-107730
75042
Type
Cl2 1
R9
Res, comp,
Ik
±10%,
Iw
4704-109371
01121
GB1021 1
R12
R13,R14
SI
Res, met
flm, IM,
matched
set
with
A7R37
Res,
met flm,
100k
±1%,
l/2w
Switch,
rotary,
RANGE, DC
Section
4705-245597
4705-151316
5105-254573
89536
75042
89536
4705-245597
Type
CEC-TO
5105-254573
1
2
1
D
S2
Switch,
rotary,
POWER
5105-242917
89536 5105-242917
1
S3
Switch,
rotary,
NULL
5105-242875
89536 5105-242875
1
S4
Switch, rotary,
MODE
5105-250555
89536 5105-250555
1
S4A
Switch
wafer,
MODE,
deck
"A” 5105-250530
89536
5105-250530
1
20
Coupler,
power switch,
mode
wafer 2404-104505
89536 2402-104505
2
21
Cover,
bottom
(not illustrated)
3156-230383
89536
3156-230383
1
5-27
o no «
Page 80
5-28
Figure
5-9,
893AR AC/DC
DIFFERENTIAL
VOLTMETER
(Sheet 1
of
2)
893A
Page 81
REF
INDEX
DESIG NO
DESCRIPTION
STOCK
NO
MFR
MFR
PART
NO
Cover, top (not illustrated)
3156-230375
89536
3156-230375
Dial,
0-9
2403-232215
89536
2403-232215
Dial,
0-10
2403-232207 89536
2403-232207
Dial,
0-100 2403-242859
89536
2403-242895
Foot, plastic (not illustrated) 3155-230037 89536
3155-230037
Indicator,
ON-OFF flag
3158-231886 89536 3158-231886
Rack Mounting Kit (not illustrated)
2906-243287
89536
2906-243287
Shaft, power switch
2406-231860 89536
2406-231860
Tilt stand (not illustrated)
3154-231407
89536
3154-231407
Trim strip, front
(not
illustrated) 3154-230813 89536
3154-230813
Trim strip, rear (not illustrated) 3156-231852
89536 3156-231852
Trim
strip,
side
insert (not
illu-
strated)
3155-230888
89536
3155-230888
Figure
5-9.
893AR AC/DC
DIFFERENTIAL
VOLTMETER (Sheet 2 of
2}
Page 82
INDEX
NO
DESCRIPTION
STOCK
NO
TOT
QTY
REC
USE
CODE
FRONT
PANEL ASSEMBLY
(893AR)
Figure
5-10
Cap,
piste, 0. 047uf
±20%,
1. 2kv
(across
J2
and
J3)
Binding
post,
red,
HI
Binding
post, red,
LO
Binding
post, black,
GROUND
Res,
comp,
lOOM
±10%,
l/2w
(across
J2
and
J3)
Handle
Knob, Digit
Knob, NULL SENS,
MODE,
RANGE
Knob, POWER
Link,
shorting
Panel, front
1507-182683
2811-226308
2811-226308
2811-226282
4704-190520
2404-
246306
2405-
158949
2405-158956
2405-235689
2811-101220
1406-244673
99217
58474
58474
58474
01121
89536
89536
89536
89536
24655
89536
MR473L12
DF21RC
DF21RC
DF21BC
EB1071
2404-
246306
2405-
158949
2405-158956
2405-235689
938L
1406-244673
2
2
REF
1
1
2
4
3
1
1
1
Figure
5-10.
FRONT PANEL ASSEMBLY
(893AR)
5-30
893A
Page 83
REF
INDEX
DESIG
NO
DESCRIPTION
REAR PANEL
ASSEMBLY
(893AR)
Figure
5-11
Diode, silicon, 1
amp,
100
piv
Diode, silicon,
1
amp,
100
piv
Diode, silicon,
1
amp,
100
piv
(not
illustrated)
Diode, silicon,
1
amp,
100
piv
(not illustrated)
Fuse, slow
blow,
l/8
amp,
250v
(for 115v
operation)
(not
Illustrated)
Fuse,
slow blow,
1/16
amp, 250v
(for 230v
operation)
(not
illustrated)
Connector, male, 3
contact
Switch, slide
Transformer, power
Holder, fuse
Panel, rear
STOCK
NO
TOT REC
USE
QTY QTY CODE
4802-116111 05277
IN4817 REF
4802-116111 05277
,
1N4817 REF
4802-116111 05277
;
IN4817 REF
4802-116111 05277 IN4817 REF
5101-166488 71400
Type
MDL 1
5101-163030 71400 Type MDL
X
2109-222612
82389 AC3G
1
5106-226274
82389
46256
-LF 1
5602-223990
89536
5602-223990 1
2102-160846 75915 342004 1
1406-231795
89536
1406-231795
1
Figure
5-1
1.
REAR PANEL ASSEMBLY
(893AR)
5-31
Page 84
REF INDEX
DESIG NO
DESCRIPTION
AC/DC DIFFERENTIAL
VOLTMETER-
BATTERY
OPTION
-
Figure
5-12
Note: The
basic Model
893A or 893AR
can
be modified in
the field by installing
the
Battery
Option Kit, part
number
2906-
242420.
The kit includes
BTI, DSI and
the power
knob.
Battery
pack
Battery,
Ni-Cad,
1.2v
Holder,
battery
STOCK
NO
893A-01
893AR-01
MFR TOT
REC
USE
PART
NO
QTY
QTY
CODE
3158-232496
89536 3158-232496
1
4002-160390
06860
1.2SCL
1^
3155-232488
89536 I 3155-2324881
2
Lamp,
incandescent,
24v (See Figures
3901-218354
71744 1252
5-1
and 5-9)
Knob,
POWER
2405-235671
89536 2405-235671
AC/DC
DIFFERENTIAL
VOLTMETER
RECORDER
OUTPUT
OPTION
Figure
5-12
Note:
The
basic
Model
893A or 893AR
can
be modified
in the field
by installing
the Recorder
Output
Option Kit, part
number 2906-242438.
The kit includes
J5,J6, RIO, Rll, and
the A6
P/C
assembly.
Recorder
Output P/C
Assembly
(See
Figure 5-12)
Binding
post, red, HI
Binding
post, black, LO
Res,
var, comp, I0k±20%,
l/2w
Res, comp,
10k
±5%,
l/4w
(mounted
on RIO)
Res,
corap,
lki5%,
l/4w
893A-02
893AR-02
1702-239301
89536
(891A -4201)
1702-239301
2811-226308
58474
DF21RC
2811-226282
58474
DF21BC
4701-162800
12697
Series
37
4704-148106
01121
CB1035
4704-148023
01121
CB1025
RECORDER
OUTPUT
P/C
ASSEMBLY
1702-239301
89536 1702-239301
REF
Figure
5-12
(891A-4201)
Cap,
elect, lOuf
+50/-10%,
25v
1502-170266
73445
C426ARF10
1
Tsts, germanium,
PNP
Tstr, germanium,
NPN
Tstr,
germanium,
PNP
Tstr,
germanium,
NPN
4805-182709
01295
GA3938
4805-182691
01295
GA3937
4805-182709
01295
GA3938
4805-182691
01295 GA3937
893A
Page 85
OVCA
Figure
5-12.
BATTERY AND
RECORDER
OUTPUT
OPTIONS
5-33
A
Page 86
REF INDEX
DESIG
NO
DESCRIPTION
Res,
comp, 22k
±5%,
l/4w
Res, comp,
22k
±5%,
l/4w
Res, comp, 22k
±5%,
l/4w
Res, comp, 22k
±5%,
l/4w
Transformer,
recorder output
STOCK
NO
MFR TOT
REC
USE
PART
NO
QTY
QTY CODE
4704-148130
01121
CB2235
4704-148X30
01121
CB2235
4704-148130
01121
CB2235
4704-148130
01121
CB2235
5602-242347
89536 5602-242347
1
893A
Page 87
{4 PL
-
2 TOP
2 BOTTOM]
(4 PL
-
2
TOP
2 BOTTOM]
12
PL TOP a
9
)
BOTTOM AT
REAR)
<8
PL
^13)
BOTTOM
INSTALLATION)
KNOB (FROM
ITEM
3
,
FIGURE 1)
REMOVE THESE
TWO
SCREWS
(BATTERY
INSTRUMENT
ONLY)
AFTER
COMPLETING ASSEMBLY. SEE THAT HANDLE
DETENTS
PROPER LY
INTO
"FEET" ON
BOTTOM COVER
ITEM
PART NO.
893A-5in
DESCRIPTION
QTY
5
232)16
891A-2024,
CAUTION DECAL
1
6
156364
SPEED
NUT, NO 6
BLACK
8
7
156489
SCREW NO
6-20
*
3/8 TRUSS
4
8
230169
MEE
•
2024
COVER, BOTTOM
1
9
230789
MEE
-
2080 REAR
TRIM
2
10
230037
MEE -8026
FOOT
4
11
152140
SCREW
NO
6-32
X 1/4
PHP
4
12
177030
SCREW
NO
6-32 x 1/2 RHP
4
13
218131
SCREW NO 6-B
x 3/8
FHP
8
14
194183
NAMEPLATE
1
15
244624
893A-2009
DECAL
1
ITEM PART NO.
891A-5011
DESCRIPTION QTY
12
1 14249
SCREW 6-32x3/8 RHP
4
15 24 2941
891A-2025 DECAL
1
7/23/73
Figure
5-13.
BATTERY INSTALLATION
INSTRUCTIONS
(Sheet
1
of
2)
5-35
893A
Page 88
ITEM
1
PART NO..
893A-5in DESCRIPTION QTY
1
250290 893A-5006 BASIC UNIT ASSEMBLY 1
2
244962 891A-4007 REAR PANEL
ASSEMBLY
1
3
242420 891A-7001 BATT
OPTION 1
4 223890 SCREW NO
8-32
x 1/4 PHP 8
1.
[T;>ITEM 3 IS
FURNISHED
AS
A "KIT” &
CONTAINS BATTERY PACK.
LAMP, POWER
KNOB. AND ALL
NECESSARY HARDWARE
MOUNTING SEQUENCE OF
HARDWARE FOR
LAMP
&
BATTERY
PACK
IS AS
SHOWN ON
drawing: knob is installed
on
page
20FTHESE
INSTRUCTIONS.
2.
LAMP
(ITEM 31
HAS
2
WIRES. EITHER OF
THEM
MAY GO TO
TBANSFORMER-
ITEM
PART
NO 89IA-5011 DESCRIPTION QTY
1
233031 B91A-5000 BASIC UNIT ASSEMBLY 1
3. WIRE
BATTERY PACK 8. LAMP TO ITEMS 1 &
2
PER VIEW
AT
LEFT WIRE MAIN HARNESS
&
POWER
SWITCH
TO
ITEM
2
PER DETAIL 1
4,
[T>-89!A ONLY.
5-36
Figure
5-13.
BATTERY
INSTALLATION INSTRUCTIONS
{Sheet
2 of
2) 7/23/73
893A
Page 89
UH-6A
5-9.
SERIAL NUMBER
EFFECTIVITY
5-10. A
Use
Code column is provided to identify cer-
tain
parts tliat have been added, deleted, or modified
during
production of the Model 893A
and
893AR, Each
part
for
which
a
use code has been assigned may be
identified
with
a
particular instrument serial number
by
consulting the Use
Code Effectivity List below. All
parts
with no code are used
on all instruments with
ser-
ial numbers
above 123.
USE
CODE
EFFECTIVITY
CODE
Model 893A and
893AR Serial
number
123 and on.
A
Model 893A serial number 123 thru 168.
Model 893AR serial number 123 thru 153.
B
Model
893A serial number
169 and on.
Model
893AR
serial
number 154
and on.
C
Model 893A serial number 123 thru 170.
Model 893AR serial number 123 thru 203.
D
Model 893A serial number 171
thru 508,
Model
893AR
serial
number 204 thru
254.
E
Model
893A serial number 123
thru
243.
Model 893AR serial number
123
thru
203,
F
Model 893A
serial
number
244 and on.
Model
893AR
serial number 204
and
on.
G
Model
893A
serial number
509
and on.
Model
893AR
serial number 255
and on.
H
Model
893A serial
number
171
thru 1503.
Model 892AR serial number 204 thru 353.
I Model 893 serial number
123
thru
988.
J
Model 893
serial number
989 and on.
K Model 893
serial number 123
thru 1353.
L Model 893 serial
number 1354
and on.
M Model
893 serial
number
123
and
on.
N
Model 893A/AC only.
O Model
893 serial number
123 thru
1863.
P Model 893
serial number 1864
and on.
7/23/73
5-37
Page 90
Page 91
DIFFERENTIAL
VOLTMETER
SCHEMATIC
NO,
1
(SHT
1)
Page 92
Page 93
DIFFERENTIAL
VOLTMETER
SCHEMATIC
NO.
1
(SHT
2[
Page 94
Page 95
Page 96
Page 97
FRONT
PANEL
KADOUT
DIALS
(t iHS)
a NId ZV OX
L
SNW
a ox
s
SNW
a
ox
9
SNu
a Ox
2
^
o.^
a’-’
wt“
h
Page 98
Page 99
IX
A-1.
CODE TO NAME
A-2. The following five digit code numbers are
listed
in
numerical sequence along with the
manufacturer’s
00213 Uvctronla Corp 0.3877 Trtiiuiitrm
lllcclroiik Corp,
Uoik’Mt'r. Nov York Wiikcfivid. Miitrsaclmvctis
00327 Wd«
7
» IpitftmKlimal,
Int
03888 Pyronini
RusbiorCo., inc.
Wcsilakv.
Oltio Cedar Knnlls, Nbw
Jersey
006S6 AVJOVOM Cotp.
03911 Cluliex Corp
Now
licOford. M;i»it(;liti«il<» New York, New
York
00686 nim C;ipudioi!i 03980 Miilrliead Instruments,
Inc.
I’jssak. Nifw
Jurscj- Mountulnsfde.
New
Jersey
00779
AMIMnv 04 009 Arrow iliiti
and ilcitemeii
Ihitrlvlvcrp. I’vrin«ylv!inki lilecironicComptiiiy
iitirifaid. Cuitneeik-u(
01121 Alluii-Iioidk)’
C 0.
Milu'imktfc. WNcontin
04062
Replaced by 72136
OI28I TKW Scmkondticiors
(VI202
Replaced
by8I3l2
l.uwMdiik.Culirnrnb
04217 Ksse.v Wire
Cor;>
01293 T«xa* liisirumems, Inc
Wire
& Cubic Die
Sumkonduviot Conipnnvim Dtv.
Aniilteim.. Ciilifotiiia
[3iill:is
Tcmiv
1M22! Aemco, Div. of
01686 RCL
C.kuronks
Inc
MIdtex
Inc.
Mundiosicr, New Hempviiire
Munkaid, Mitincsuia
01730 Ddciod
04222 ACTOvoxCorp
. (M<il
Myrtle Ucacli. SuiKl) Carolina
01K8.1 Dciirtiom Llcctronk's
Inc.
Orkitidci. MorlUii
04643
Rcptiiced
by
75376
021 H
i'tfrtiixciibc Cofp
S:«cccrlic«
New York
04713 Motorola Semiconductor Products Inc,
Pliociiix,
Arkona
02606 lU'phiccd by 15801
05082 Replaced by 94154
02660 Ampbunot-Uorp lllcct Ci'fp
liroailvicvv, Illinok
05236 ianathan Mfp
Co.
l-u!!emm. Calilbrnia
02799
Afco Capjcltors, I(vc
Torrence. C :!!it'orr)ia
05277
Westinjtluiusc Electric
Corp.
Seiiiicondiiclor
Dept
03508 Genera! Klectric Ctj
Seiiiiconsiuciot Products
Yoiinttwood. Pennsyivanb
Sy/actise. New Ycr7
05278 Replaced
by 4 3543
03614 Repiiiccd by 71400
05397 Union Carbide
Corp
l-U'clronics Div,
03651 Replaced by
446S5
Cleveland Ohio
DSI'JI !:!dema C orp.
05279 Soittlf.vcs!
Machiite
&
Pla.stic
Co
Compton, Caitl'nrnirj
Uis Anyeles, California
name and address to which
the code has been
assigned.
The Federal Supply Code has been
taken from
Catalo^ng
Handbook
H
4-2, Code to
Name.
05.397
Union Carbide Corp
07263 l-aircbtld Samkondiic
lu;
Eiectrunlcs DIv.
DIv.orruIrcliildCunieta
New
York,
New
York
&
Insiruineril Curp.
iMiiiiniaIn
View,
C
aiiruriiiu
05571 Spru^nte Electric Co.
Pacific DIv,
07344 Ilircliur Cn
.
Ittc
Los Angeles, California
Ritchcsicr, New York
05574
VIkIrit!
Ittdiisitivs
07792
Lvrtiia Ettgiriuering Corp.
CluiisKurth,
CjlIToitila
Nortlriiinpum, Mas.suclitiset
is
05704 Aluc, Inc
Glendale. Caltfornb
079
1
0 Tekdyne Corp.
(Cuntinunlal Device)
liawlhiitne,
Callforitla
05820 Wakefield
Engineering tiid
Wakefield,
Massucluisetls
08225
Indusirn Transistor Corp.
Long island City,
New
York
06001 Gcrterul Ulocctlc
Company
Capacitor Department
08530 Reliance Mica
Corp,
Iimo.Soiiili
Carolina
Urookiyn, New York
06136 Kcpliiccdlty
63743
08792 Discontinued
06473
Arnplicnol Space & Missile Sys.
Clwisworllt, California
08806 General Electric
Co,
MIntulure Lamp Depl.
Cleveland,
Ohio
06SS5 Daede Eluairlcol Insirunivnt Co.
I’cnacQok, New Hampstilre
08863
Nylomatic
Corji.
06739 Electron
Corp.
Littlciown,
Colorado
Norrisville, Pennsylvania
08988
Skottlc Electronics
Inc.
06743 Cievite
Corp
Cleveland, Oliio
Arrlibald. Pennsylvanlu
09353
C
and
K
Coitipttnents
06751 Seincor
Div
,
Components, Inc.
Plioenix, Arizona
Watertown, Massaclioseits
09423 Scientific Components, Inc
06860
Gould National Batteries Inc.
Sanl.i llaibara. California
City of Industry, California
09922 Biirndy Cnrp
Norwtilk', Connecticut
06980 V;iritm-Eimac
San Carlo.s, California
11236
CTS
of Berne
Berne, Indiana
07115 Replaced
by
14674
11237 Cbicago Tclcplione
of
07138 Wesiinehouse
Eieelric
Calif. Ine (CTC)
Corp
,
Electronic
Tube Division
Paso Robles. California
Elmira. New York
11358 Distominued
07256
Silicon Transistor Corp
11403 Best
Piodiicis
Co
Garden
City,
New
York
Chicaco. Illinois
7
-
24-73
A1
Page 100
1
i5<i:-
k,>
'IiiiK M6:
I59H9 Rcpi.KcJ l;s 17X7>!
[)iv
.it
\\
S'
! S'tki' lri:ii (
isr[i
\( irrui
16299 r.iiniiicGlti"
idikiitl! N.itih
(
afi.lina
ihl
(
.it|i
Stiisi.i riit-i ("ilil.iim.i
163.1'
Ri'pla. c! in 2K47X
i'nu'iui.
Ru'i
i MtKht.K-
r.i
16173
C.imkridi;!. Suciilillr liul Im
IklU'.iHHl ntilUih
Canihrkka- Slarylainl
12iWi<
N'.Msmi (! Sunsi
lU'fJitt i<if
(
niji
1674
2
i’ai.imimm I’laslioi
[l.iiilmtr* ( iinssi.''
ij<m
ll.nMii;}
Calikitnia
Oi.ak- 111.
167.5H IX-lo. Urniid
Chijt'UiiTit!
( aJit'tifni.j
Div liiGvncxsil
iM.iiois
Knliiimii
Imiitma
i-liilaik'Ij'lii.i llaiulk <'n
Ciinnkii kcu Jvr.ci
ITT 1
anisiin
5;iii!a Ana C.iiilDini.i
I'aMii
Ci>
.
iiii:
Sliclsiin
(
171)69 Circiiil SlruiuiiL-s Lab
U}al;!iul r'iilift.fni.i
i:327 i'siicw.iH W.s\h.;r
&
S t.smjim!: ( .i
Ocvchmi.1
Oiiiii 17X56 Silkaini\.
Inc
Snii!a> vale
.
(
islilofiiia
12-iim
H.-pl,iu.-.n>s
75IM2
17X71) Dtiven-Div oi'Tiionnis Ikli'O
Hamlin
iin.'
hut
- McGran
. !
Ji.um Co
i.aki-SlilH
WiMijiuin
ManelicMCF.
Nciv lianipMiirtf
12697
Ounistal Mr}; Cti.
Diivtr Nv'v
llamptiliiri'
1K081
Uvlva-il
12799 Jtiincsi I'kcifonic.s
18178 Viicioi.' Ene
MarytaiKl
Hd^lils. Minsmiri
12856 .Mii:rosm'iii)i>
18612
Vlsliay Inicrteeliiuiloiiy
Siurtii
MaJrv.
rsiljriiriiia
Inc.
Millvvrn. I’ciinsylvaiiia
129S9 Dk'kMin likcliimli' Corp
Svc'tl'diili.'. ATi^iuiii
18716 Vollriipiicsforp.
Hanover. Ne« JiTk'y
12969
Uiillri'iic C
orp.
IVjtcrtoxiv
M.issadtiiKtis
19429
DittainHniii'd. iitii'
89536
Ul(1.7
Tiii’misiltii) <'(i
19451 I’erlik- Madilnury & Supply Co.
I3si1I;is.Ti,'\un
Suutllc.
WiAlilii^ion
I25II Amphi
ivil
C
iirp
1971)1
liledra Ml'8- Co.
I..1IV ('aiiis.C.illliimia
Imlcpuiuk-iKi;, Kaiitas
1.16(16
Sprapii! r.luciric Cu
Tr:in»lHnr |}tv
Cimuiril.
N('« li:im[».|(iti.-
211584 llmu'lis
Ml'};. Co.
Iiulianapollii. Inilianu
21)891
Sdl'-Or{!ani7iiiy Syalcms.
128.19
Ki-pliiu'd
1)}
2,17.12
Inc.
l3al1aa.Tu\a«
141)99 Si'inU'i:li Ciirp
22767 ITT Samiooiuliidors
N’KvIisjt) I'tir). CalltoiiiM
Div <if ITT
Piiio Alio, Ciilirofnla
14
1
9.1
(
IlD'laiur
( nrp.
Santa Mimica.
(
'alil'nrnin
23050 i’roilia-l C'.onip
Co:p
Moimi
Vcnioii. Nv'v Votk
14298
Amurican C nmiiiiiKnls. liw.
21732 Tr!».'»»t
('iiii'lii'lioiskuti PcniKj'Ivtjnlti
liockvillo. Maryliiml
14655 < iirndMIiiliilki nv<:lriin!i.<>
23880 Slanfoiil Applied
riiyrnit.
Niwatk. Nim
239 36
SiiKlii Clara. Ciilit'ocnia
111 mot or iljv., Witt.
1
I’lirdy
O
146 74
IXMMiiiima'd, sw 16299
24248
llnrlln^amc.
C'alll'oiitia
SoiiOwit
1J752 r.li'ctni {'tik- Im
Div.
o(
Soiiili Citaotr Corp
San (iiibrii't. <'alil»Ilii:i
24655
Lester, Pemwylvania
General Radio C o
14869 Ikplikciihy 968.51
Wesi Coneitul MasMidtONei Is
1.5636 rka-Trn!
Iru'
24 7
5
9 l.eno\-l
nek- I'ileeifonks
N.inli'id-f.
Calirntili.l Plainrield, Nen Jersey
15X11! 1 cn«.il
1
katimiks Inc 2540,3
Amperes Lleeitonie Corp
1 rtiminssham lui'citv Seiiiicoiidiielor
.t
Reecivini;
Tube Division
158
IS
.Atiu:)i.i'
Scinic'iiiuini t.ir
Div III" Tokul}
ru- Sni
SlalersviUe lUuide Island
Muniutiin V'k'u
Calijlirsiiti
27014
Naliooal
Ss’titieonduetor
15X49 U.S!;fO
In.
( orp
Ml '.crmin
Nv« V.iik
Santa riaia.f
alil'ornia
27264 Molts i‘rodiieis
I5X9K lnicinalnin.il iliiMiiL-''
Don tiers Grove.
1
llinois
Vaduncs
(IHM) 284
25
iSohannoii liKliislries
June linn
Vcnmini
i-()7! WoFlli Tevas
2X4 7 X Deltri'l Coitirols
6615H WiiisloM
rill. 'Vronie
s Im
<
orp
Asi)ur\ I'.irk. New Jerses
Milnaiikte VVistonsiii
7056,3
Amperilc ( timpany
2X480
ilvst
lei!
I’acfcard lliiiuii
Cii\ . N'ew Jersev
I’aloAHo (
aOI'.iima
71)90.3 Ikklen
Mie
Co
< liKMeo Illinois
2X5.20
IksmanMfe C-i
Keoiluorlli N'en Jerses
71(102
liiinbat It R.idiii
( o hit
Nets
Vor) Nets York
2908.1
Monsaoli). 0 o . Inc
Santa Clara. ( aliromia
71216
T 1 Ml'NfO"
W'lllimamie ('ormeciii iii
303 2.1
illiiuiis Toot
Works,
lot
7i4IHl Hmsmann
M(e.
OiK..!}',.!
IDimiis
Dll' of MvGiaii
-
I'dison Co
Sain! i.miis Mi.ssouri
32539 Miiia Coip
Grcal Neilr.
Hen
Vmk
71450 CTS Coip
ITIsliari Imliana
32767
Griffith I’liiSSic
I’roihicis Co
Kurliitjiame,
Calilomia
71468
n'r
Cannon neciric int
Los
Anueles. Ciditornia
12879 Adviiiiced
Mediimica!
(
oittiHiitcnis
Norlliruljre. Calii'oriiia
71482
Clare.
<
i’ &
Co
ritieapo. Illinois
32897
i.eie
Teo1iiuiio}(iei>l
71590 Ceiilrulab
Div.
oi C.lohv Union
Inc.
I'rodiu
IX. Iiteorporaied
l''reqticiiej' Coiiirtil DIv,
Milwmikee. Wisconsin
Carlisle, I’eitnsylvimi;)
7171)7
Colit Coil
Co.,
tne.
33173 Cvtteral iilvclrli*
I’rovidenee.
Kliode Island
Co., Tube Dopi,
Owensboro.
Kenititky
71744
Cliiciiyci Miiiiaiure Lamp Works
Otieapn. IlliiKiis
14333 StIicoM
C.iene.rnl
7I7HS flmlt Mi'p Cn.illowatd
WesImliwMei.
( alilOTitIa
11. Jones Div.
Oiieuyo. IllinoiK
3433S
Advattevd Micro
Devices.
72005
Driver. Wilber
U
,
Co
Siinityviiie. C.iilifodtia
Newntk, New
Jersey
37942 Mallory. P
R &
Co , Inc
liiOiaiiapolis, Indian:)
72092 Raplaeed
by
(76
9
80
72136 kleciro Motive Ml').'. Co
42498
Nalioiial Company
Melrose. Mussaeliiisells
Willimartlie.Coitncetitiii
72259 Nyironies iite
43543 ^yt^ottlcs
Inc
Traitsl'otmct Co. Div.
ilerkcley Hcipitls
New
Jersey
Alpha. New Jersey
723.54
Deleted
44655
Oltittlte Mf)!. < 0.
72619
DlidifdilCorp.
Skokie. Iilin:tis
lirmtkiyii. New York
72653 Cr C
,
Icleciroitics
49671 RadloCorp.pl’Amctieit
New York. New York
lloekford, Illinois
49956
R.aylEtcon Company
72665 Replaeetl by 90303
U'slityliin. Maine
72794
DittisriisieticrC.'n.. Iiie.
West l.slip, Netv York
S3E72I
55026
Sanatiio
rieelriv Co.
SprinpiU'ld. Illinois
7292S Gudeittan Co. fCiiilloit
litdaslriesl
Cliieiiyo, lltimtis
SimpKoii lilecirie Cnmpaiiy
Clikupo. Itlinoh
72983
I'irie Teeli. I’lodiiels Ine
1‘tie,
Pennsylvania
56289 Spiaptie iHeelrie
Co.
Norllt
Aslant
s. Massadinsetls
731.38 Ikekman insiriotteots
Inc
ilelipot
Division
S84
74
.Superior Lieeltie
Co
i-iilltrlon. California
Hrisicil
C Dimenieut
71291
lliittlies Airtrall Co
i'.fccltim
Dynamies
Div
6(1.399
Turritieum Mie. Co
Tstrrenee. California
Torrineirm.
C
onneeikii!
73445 Ani|XTes ITeettonic
C orp
624611 Delelcd
Hieksville. New
Y’ork
6374.1
Ward l.eonard ITctirie ( o
73559
Catliite
hla'lrit Irtc
Mouni VVmon. New
York
Hanford. Coiintelietil
648.14 West
Ml'e.Co
735X6 f in it
!
Industries
San ) f.im iseo
Caiir.irni;!
Truilmi
New Jersey
65092 Weston instmmenls
Inc 717,34
1
1 edcral
Screw Products hit.
Newark. New
Jersey fliitai;.! tttiii.iis
A2 7
-
24-73
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