HP 412A, 412AR Operating And Service Manual

I.

:

HP

..

.

This vintage Hewlett Packard document was

preserved and distributed by

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www.

'

Please visit us on the web

..

On-line curator: Tony Gerbic

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i

(r,

,'

a

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i

f

DC

OPERATING

(HP

MODEL

VACUUM

SERIALS

PREFIXED: 301-, 3160, 424-,

AND

PART

SERVICE

NO.

00412-90003)

412A/AR

TUSE

MANUAL

VOLTMETER

I

649-

P.

1

i

OOT29-5

Copyright Hewlett-Packard

0.

Box

301,

Loveland,

Colorado,

Company

80537

1961

U.

S.A.

Printod:

NOV

1968

0

h

Model 4 12A

TABLE

OF

CONTENTS

Table

List

of

Contents

of

Tables

I

i

1

Section Page

I

GENERAL INFORMATION

1.1

.

Introduction

1.7

.

Specifications

1.Y

.

instrument and Manual Identification

.

Section

.

?

11

INSTALLATlON

2.1

.

Introduction

2.3

.

Initial inspection

2.5 . Power Requirements

2.7 . Grounding Requirements

2.10 . lnstallatiori

2.13

.

Repackaging

Section Page

I11

OPERATING INSTRUCTIONS

3.1

.

Introduction

3.3

.

Low-Level Electrical Phenomena

3.7 . Turn& Procedure

3-8

.

Voltage Measurement

3.9

.

Y

Section Page

IV

Current Measurement

3-1

0

.

Resistance Measurement

3-1 2

.

Amplifier Operation

THEORY

4.1 .

4.3 . Block Diagram Analysis

4.5.

4.7

4.9

4-1

OF

General Range and Function Selection 4-1

.

Filters

.

Modulator. Amplifier. Demodulator.

and Chopper

1

.

Cathode Follower and Polarity Selection

.........................

........................

..........................

.........................

..........................

for

.........................

OPERATION

.............................

..............................

........................

.................

.....................

...................

...............

Shipment

..............

...............

.........

....................

..................

................

...................

..................

................

...........

.....

Page

...

1-1

I

-I

1-1

2-1 2-1

2-1

3-1 3-1

3-1

3-1 3-1 3-1 3-2

3-3

4-1

Section page

V

MAINTENANCE

5.1

.

lntroduction

5.3

.

Required Test Equipment

5.5

.

Performance Checks

5.7

.

Meter Zero

5.10

.

Voltmeter Accuracy Check

5-1

1

.

Milliammeter Accuracy Clieck

5-1

2 . Ohmmeter Accuracy Check

5.13 . Input Kcsistance Clieck

5.14

.

AC Kejection Check

5.15

.

Adjustment and Calibration Proccdure

5.17 . Cabinet Removal

5.18 .

5.20

5.21 . Cathode

5.22 . Meter Electrical Zero Adjustment

5.23

5.24

5.25

5.27 . Front Panel Indications

5.29 . Power Supply and Amplifier Checks

5.33 . Modulator Clieck

5.34

5.36

5.37

5.39

541

546 . Input Cable Keplacemcnt

Section Pap

VI

REPLACEABLEPARTS

6.1

64

6.6.

Section l’ilgc

VI1

CIRCUITDIAGRAMS

7.1

Mechanical Adjustment of Meter Zero

.

Hum Balance Adjustment

Amplifier Gain Adjustment and

.

Meter Calibration

Olimmeter Adjustment

.

Troubleshooting

.

Modulator Replacement

.

Demodulator Check

.

Demodulator Replacement

.

Switch Checks

.

Adjustment

Components

.

lntroduction

.

Ordering Information Non-Listed Parts

.

Introduction

..........................

.........................

...............

...................

.........................

.............

..........

............

...............

..................

......

....................

....

..............

Follower

Bias Adjustrncnt

......

........

...................

................

......................

...............

......

....................

...............

..................

.............

......................

of

Factory Selcctcd

.......................

..............

....................

.........................

..................

......................

.........................

5-1

5-1 5-1 5-1

5-1

5-2

5-3 53

53 53

5-3

5-5 5-5

5-5

54

56

54

5-7

54

5-8

54

5-0

6-1

7-1

Number

1.1

.

Specifications

3.1 . Voltage and Current in Resistance Measurements

5.1

.

Test Equipment Required

5.2

.

Millianimeter Accuracy Check

~

..

.............................

............................

....................

................

LIST

OF

TABLES

Page Number

5.3

1.0

54

3-2

54

5-2

5.5

6-1

.

Input Resistance Chccks

.

Power Supply Voltages

.

Tubc Replacement

.

Rcplaccablc Parts

..........................

Pagc

.....................

.........................

:54

541

iii

5-3

6-2

n

List

of

Illustrations

Model

4

12A

n

.1

t,p’

Number

1-1.

Model

412A

DC

Vacuum Tube

Voltmeter

4-1.

Block Diagram

5-1.

Input Resistance Check

5-2.

AC

Rejection Check

53.

Location

54.

Input Circuit Board

5-5.

Modulator Waveform

54.

Demodulator Assembly

5-7.

input Cable Connections.

5-8.

Simplified Schematic, Voltmeter

Switching

5-9.

Simplified Schematic, Ammeter

Switching

.

. . . .

. . . . . . .

of

Adjustments

. . . .

. . .

. . * .

.

. .

.

. .

.

. . . . . .

.

. . . .

.

. . . . . .

. . .

.

. . . .

.

. .

.

. . .

.

...........

.

. .

.

...........

. . . . .

...........

.

...........

. . . . .

. .

.

...........

. . .

. . . . .

...........

. . . .

...........

.

. . .

.

...........

.

. .

.....e.....

,

. .

.

LIST

’

OF

ILLUSTRATIONS

Page Number

5-1O.Simplified Schematic, Ohmmeter

,

.

,

1-1

,

.

,

.

..

.

...

.

..

...

.

.5-10

.

.5-11

4-1

5-2

53

54

56

5-7

s-8

59

6-1.

6-2.

6-3.

7-1.

7-2.

7-3.

74.

7-5

.

. . .

.

Switching

Location

Cabinet Model

Location

Rack Model Voltage Location of Chassis Mounted.Parts,

Cabinet Model Location

Rack Model Location Schematic Diagram

Power

of

Probe

of

Supply Backdating

. . . . . .

Mechanical Parts,

.

. . . . . . . .

Mechanical Parts,

.

. . .

. . . . . . .

Assembly

. . . .

Chassis Mounted

. . .

Switch

. . .

.

. . . .

.

. . . .

. . .

. . . . . .

.

. . . . . . .

. . . .

Components

.

. . .

.

Parts,

.

. . . . . . .

.

. .

. . .

.

. .

..........

.

..........

.

..........

e.........

..........

.

..........

Page

.

.5-I

. .

6-5

.

6.6

. . 6-7 .

.

7-2

. .

7-3

..

74

.

7-5

.

7-7

2

8

b

'5

Section

VOLTMETER

9

b

AMMETER

I

Table

1-1.

Voltage Range: Positive and negative voltages from

millivolt

ranges

Accuracy

Input Resistance:

and

30

100

200

AC Rejection: A voltage at power line

line frequency reading

1500

fuull

scale to

:

+

1

%

of full scale on any range

10

mV ranges

megohms

21%

megohmsf.l% megohms

less

t

40

than

1

volts.

1000

volts full scale in

megohms

on

30

on

100

%

on

300

dB

greater

1%.

Peak voltage must not exceed

1%

on 1 mV, 3 mV,

mV range

mV range mV range and above

or

twice power

than full scale affects

Specifications

1

13

AMPLIFIER

Voltages and Currents:

Open Circuit Short Circuit

Range

XI

XI0

XI00

XlOOo

XlOK

XlOOK

XIM

XlOM

Xl00M

Voltage Cain:

AC

Rejection: 3 dB at

Volts

10

mV

100

mV IV 1v 1

1v

1v 1v

1v

1000

maximum

1

Hz,

80

Current

100~

.Olp

dB at

Model

10

mA

10

mA

10

mA

lop

'P

.lp

50

A

A A

and

4

60

12A

Hz

d

Current Range: Positive and negative currents from

1

microampere full scale to 1 ampere full scale in thirteen ranges

Accuracy

v

tnput Resistance

Range Resistance* Voltage

:

2

2% of full scale on any range

:

tnternal Shunt Full

Scale

Drop

Output: Proportional

full scale; maximum current, corresponds to

Output Impedance:

Less

Noise:

than 5 mV

Drift: negligible

to

meter indication; 1 volt at

1

.O

on upper scale.)

Less

than 2 ohms at dc

RMS

on

1

mA.

any range

(Full

scale

GENERAL

.001

mA

.003

mA

.01

mA

.03

mA

.I

mA

.3

mA

1

mA

3

mA

10

mA

30

mA

100

mA

300

mA

1000

mA

*For

total insertion resistance add

25

rcsistance at

C

I000

3

I6

100

3

I

.6

IO

3.16

.3

ohms

ohms ohms ohms ohms ohms

1

16

.1

.I

ohm ohm ohm olim olim

ohin

ohm

0.07

1

mV

0.9486

1

mV mV mV

1 mV

0.9486

10

30

100

mV

1

mV

1

mV

3

mV

ohms copper lead

Isolation Resistance: At least

by 0.1~

F

between common terminal and case

100

megohms shunted

(power line) ground

Common Mode Rejection: May be operated up to

500

Vdc

or

130

Vac from ground

f10%,

5040

Hz,

35

11-1/2

W

in. high,

7-1/2

Power: 115/230 V Dimensions: Cabinet Mount:

in. wide,

10

in. deep

Rack Mount:

OHMMETER

Hesistaticc Ibiige: Rcsistancc from

center-scale to

raiiges

decade

a

Accuracy:

f-

5%

of

IO0

niegolims center-scale in nine

reading froni

scale

'I

14

0.3

to 3 on Ohms

I

olim

001

29-5

Model

4 12A

Section

I

SECTION

GENERAL

1-1.

INTRODUCTION.

1-2.

The Hewlett-Packard Model

Tube Voltmeter is

a

multifunction instrument which measures the entire range resistance normally encountered in electronic equipment.

1-3.

The Model mV full scale to arranged in a

of

full scale. The input circuit

from

power line ground.

14.

The Model current from accuracy

3,

1-5.

412AIAR

of

10

sequence.

Resistance measurement capability

is

2%

from

412AIAR

IO00

V full scale in thirteen ranges

1,3,

10

sequence. Voltmeter accuracy is

412AlAR

1.OpA

of

full scale. Current ranges are also in a

1.0

measures positive

full scale

ohm center scale

412A/AR

of

dc voltages, current, and

DC

Vacuum

measures dc voltage from

is

isolated from the case and

or

negative dc

to

1.0

A

full scale with an

of

the Model

to

I00

megohms

1.0

1%

1,

I

INFORMATION

center scale in nine decade rangcs. Resistaiicc nieasureiiieiit

is

5%

accuracy

16.

The Model

between

voltage proportional to the input. Ainplificr giiiil is froiii

-1000

to

t1000,

depending on range selected.

1-7.

SPEC1

FlCATlO NS.

1-8.

Complete specifications

are listed in Table

1-9.

INSTRUMENT AND MANUAL IDENTIFICATION.

1-10.

Hewlett-Packard uses a twoscctioii cigltbdigit scrial number number

(OOO-00000).

of

your instrumcnt do not agrcc witti thosc

title page of this manual, changc sliects supplicd

will

manual

explain the diffcrenccs bctwccii instrument and the Model manual.

'

.3

and

3

412AIAR

1-1.

If

has a dc aiiiylifier output

for

the first tlircc digits

412AIAll

on

the resistance scale.

the dip- Modcl41

of

dcscribcd

2AIAR

tlic

scrial

on

tlic

with

tlic

your

in

lliis

412A-A-30188

Figure

00

1

295

1.1.

Model

412A

DC

Vacuum Tube Voltmctcr

0

Model 4 12A

h

Section

I1

2-1.

INTRODUCTION.

2-2. Tliis section contains instructions necessary for installation

the Model 412AIAR

DC

Vacuum Tube

of

Voltmeter. Included are initial inspection procedures,

cy

power and grounding requirements, installation information, and instructions for repackaging for shipment.

2-3.

INITIAL INSPECTION.

2-4.

This

instrument was carefully inspected both

and

mechanically

of

free

mars or scratches, and in perfect electrical order

upon receipt. inspected for physical damage clcctrical procedure outlined in Paragraph

electrically before shipment. It should be

To

confirm this, the instrument should be

in

transit.

performance

of

tlic instrument, using the

5-5.

If

there is damage or

Also

deficiency, see tlic warranty on the inside front cover of this manual.

2.5.

POWER

2-6.

P

Y

The Model 412AIAR can be operated from any source slide switch Power dissipation is approximately

REQUIREMENTS.

of

115

or

230

on

the rear panel selects the desired voltage.

volts at

50

or

35

60

Hz.

watts.

The

SECTION

IN

STACLATIO

test the

115/230

V

II

N

2-1

0.

INSTA 1 LATlO N.

2-1

I.

The Model 412A is intended

instrument, having a top-mounted handle and rubbcr fcct.

2-12. The Model 412AR is intended for rack mounting. Front panel height

2-13.

REPACKAGING

2-14.

The following paragraphs contain a general guidc for repackaging the original container is

is

5-7/32 inches.

FOR

SHIPMENT.

of

tlie instrument. Rcfcr to Paragraph

to

be

uscd;

have any questions, contact your Service Office. (SCC Appendix

B

NOTE

If

the instrumcnt is to be sliippcd

I

Icwlctt-i’ackard for scrvicc attach a tag to tlic instrumcnt idcntifying the owncr and indicating tlic scrvicc repair

to

be accomplislicd. lncludc tlic

model number

of

tltc instrumcnt. corrcspondcnce, identify tlic instrumcnt by modcl numbcr, scrial numbcr prcfix, and scrial numbcr.

for

use

as

a

2-16

if

it

is

not.

local

-lip-

Salcs

for office locatiwis.)

to

or

repair.

or

In

any

bcncli

2-15

If

you

and

if

G

R

0

U

N

D

I

NG

2-7.

2-8.

To protect operating personnel, the National

REQUl

Electrical Manufacturer’s Association that tltc instrument panel and cabinet

R

EMENTS.

(NEMA)

recommends

be

grounded. This instrument is equipped with a threeconductor power cable wluch, when plugged into an appropriate receptacle.

on

grounds the instrument. The offset pin

the connector is

tlie ground wire.

2-9.

To

preserve the protection feature when operating the

instrument from a twocontact outlet, use a threeprong

4b

two-prong adapter and connect the green pigtail adapter to ground.

NOTE

Operating the Model 412A/AR without grounding the third (power line ground) wire

of

the power cable will result

of

the meter and oscillation

1

29-5

zero offset the pointer.

4

J

00

in

of

2-15. Place the instrumcnt suitable packing material and metal bands.

be

purchased from your ncarcst

If

original containcr

in

original conhincr with

scat

wcll

with strong tapc

is

not aviilablc, onc

hp

Salcs

and

or

CBR

Scrvicc

Office.

2-16.lf original container

is

not to hc uscd, procccd

as

follows:

a. Wrap instrument

in

hcavy

papcr or plastic hcfurc

placing in an inncr containcr.

to

on

the

b.

Place packing material around a11

instrumcnt and protcct panel facc

strips

.

with

c. Place instrument and inncr containcr

carton tapc

or

wooden box and scal wcll with strong

or

metal hands.

sidcs

of

cardhturd

in

a hcavy

a

d. Mark shipping containcr

INSTIWMENT,”

“FRAGILE,” ctc.

“DI~LICATE

2-1

hlodcl4

12A

Section

111

SECTION

0

PER

AT1

N

G

3-1.

INTRODUCTION.

3-2.

The

-lip-

Model 412A/AR

Voltmeter nieasures dc voltages from

full

lo00 V

Current measurement ranges are from

1000

to The Model

1.0

ohm center

Resistance measurenicnt accuracy is

.3

and

provided.

+1000,

1

.O

V

at full scale. and maxinium current load is

3-3.

LOW-LEVEL ELECTRICAL PHENOMENA.

34.

Stray low-level electrical phenomena may cause error

in

low voltage measurements. When using the lower voltages

of the Model 412A, consider the possibility voltages produced by thermoelectric effects, residual charges on capacitors, battery action, cables,

scale with

mA

full

scale, with accuracy

41

2A/AR makcs resistaricc measurements from

3

on

the ohms scale. A dc amplifier output is also

Voltage

depending

an

accuracy of

scale

to

100

gain of tlic amplificr is from

on

range selcctcd. Amplifier output is

DC

Vacuum Tube

1.0

mV full scale to

1%

of

full

scale.

0.001

mA

full

scale

of

2%

of

full scale.

megohms center scale.

5%

of

reading between

-1000

to

1

.O

mA.

of

low-level

or

flexing

of

coaxial

IN

STRU

3-7.

3-8.

111

CTiO

TURN-ON PROCEDURE.

a. Make sure the proper fuse is installed for operation

with the power line voltage to be used. A slow-blow fuse should be used for operation, and a operation.

b. Connect

Allow

VOLTAGE

NS

BEFORE CONNECTING PRIMARY POWER, MAKE SURE THE REAR PANEL 115/230 V SLIDE SWITCH

IS

SET

TO

THE POWER LlNE VOLTAGE INCORRECT SETTING MAY

RESULT IN DAMAGE TO THE INSTRUMENT.

to

ac power and turn instrument ON.

a

S-minute warm-up period.

MEASUREMENT.

TO

BE

0.4

A slow-blow fuse for

USED.

0.6

I

IS

230

A

V

3-5.

The voltagc probe, currentlresistance lead, and common lead have a very low thermoelectric effect with copper, the most commonly used conductor. However, some component leads such as transistors and reed relays may have leads

of

made thermoelectric voltage when joined with copper. Whenever possiblc, connect tlic possible, the voltage probe and common lead should both

In:

conncctcd

and both connection points maintained at the same

tc

111

pcra

34.

To minimize tlic possibility making probe tip and common lcad alligator clip are clean.

surc

tlic component leads or other points of connection are clean. The prcsence niay cause noticeable nieasiirement error due to battery action.

of

the Model 412A/AR are all designed to

such alloys as nickel-iron, which produce a

412A

leads to copper. If this

to

the

smic

kind

of

inctal compncnt lead,

t

urc.

of

battery action when

low

voltage mcasurcments, make sure the 412A

Also

of

sonic chemicals such

NOTE

Operating the Model 412A/AR without grounding the third (power line ground)

of

wire zero offset the pointer.

the power cable will result in a

of

the meter and oscillation

as

solder flux

of

is

not

be

a.

Set

FUNCTION switch to VOLTS, and select

proper polarity.

b. Set RANGE switch to desired range.

set

switch to high range and downrange as

necessary.

c.

Connect VOLTS and component, and read voltage.

DO

NOT OVEKLOAD THE INSTRUMENT. MOMENTARY OVERLOADS UP TO TEN TIMES FULL SCALE WILL NOT DAMAGE THE INSTRUMENT; HOWEVER,

CURRENT SHUNTS, AND

INTERNAL RESISTANCE

STANDARDS ARE NOT PROTECTED FROM EXTREME OVERLOAD.

33.

CURRENT MEASUREMENT.

a. Set FUNCTION switch to

b.

Set RANGE switch to desired range. select high range and downrange as necessary.

COM

If

in doubt,

leads across circuit

MA.

If

in doubt,

or

00

1

29-5

3-1

section

.

3-10.

111

c. Deenergize circuit

d. Connect

COM leads.

e.

Energize circuit,

up-scale indication, and read current.

When making current measurements,

make

the circuit common

ground (&)terminals on rear panel.

RESISTANCE

a.

Set

FUNCTION switch

b.

If resistance make sure

c.

Connect measured, using

to

412A

into circuit,

NOTE

sure

there

is

no connection between

MEASUREMENT.

to

be

power

is

412A

across circuit

MA/OHMS

be

measured.

set

POLARITY

6)

and power line

to

OHMS.

measured

turned

off.

and COM leads.

using

MA/OHMS

switch

is

part of a circuit,

or

component

to

and

for

be

Model

41

2A

d.

Set

RANGE switch

near center scale as possible, and read resistance on

OHMS

scale.

3-1

1.

When measuring the resistance such as transistors and diodes, it is often desirable what voltage and current were present in obtaining the resistance measurement. Table voltage and shortcircuit current available at during resistance measurements. Voltage and current are read on the top scale The meter reading is directly proportional across the device being measured, and inversely proportional device being measured on the

.25

on

the

top

100

mV (Table across the device. To determine the current, subtract the meter reading multiply by the shortcircuit current listed in Table Since the current shown indicates measured. The resistance measurement, then, indicates an equivalent resistance

20

mV, and a current

of

to

the resistance scale. The meter

scale. Since full-scale voltage for the

a

current

of

the current.

34),

of

.2

from the full scale reading

of

so

that meter indication is as

of

non-linear devices

3-1

lists the open-circuit

the

412A

the meter

this indicates a voltage

for

all

resistance ranges.

to

the voltage

As

an example, assume that

XI0

range gives a reading

also

indicates

XI0

of

for

the

XI0

range

is

10

8

mA through the device being

2.5

ohms, with an applied voltage

of

8

mA.

to

know

leads

.2

range is

20

mV

1,

and

3-1

mA,

this

a

of

on

.

Resistance Range

XI

XI0

XI00

X1

K

XlOK

XlOOK

XIM

XlOM

XlOOM

Table

3-1.

Voltage and Current in Resistance Measurements

1

OpenCircuit Volts

1

on top scale)

(at

10

mV

100

mV

IV

1v

IV

1v

ShortCircuit Current

0

on tot, scale)

(at

10

mA

10

mA

10

mA

1

mA

l00pA

IO

pA

lPA

0.1

pA

0.01

pA

3-2

00

1

29-5

Model

4

12A

Section

111

3-12.

AMPLIFIER OPERATION.

3-13.

The Model used to drive devices permanent record

4

412A/AR

such

of

measurements. Output level is

DC

Amplifier Output may be resistance) may cause errors in meter indication and

as an analog recorder to provide a amplifier

1

.O

volt range

at full scale; maximum rated load current is currents

to

in

excess

of

1.0

gain.

Amplifier gain is from

-1000

on the

loo0

mA (less than

+lo00

range.

1000

1

.O

mA.

ohms load

on the

Load

,001

Y

00 1 29-5

I‘

3-3

Model

41 2A

Section

1V

SECTION

THEORY

4-1.

GENERAL.

4-2.

The kp- Model

amplifier circuit to produce a meter indication proportional

to the voltage, current, or resistance being measured.

4-3.

BLOCK

44.

Figure The following paragraphs describe operation of the various circuits.

4.5.

RANGE AND FUNCTION SELECTION.

4-6.

The Voltage Divider. Current Shunts, and Resistance Standards circuits provide a input in all ranges and functions. Full scale reading Simplified schematics

and

functions are shown in Figures

47.

FILTERS.

4-8.

input filtering is provided to attenuate any ac components present in the input signal. The second fdter section filters the Demodulator output.

DIAGRAM ANALYSIS.

4-1

of

1

on

412AIAR

is

a block diagram

the top scale of the meter for all ranges.

of

the switching circuits

uses a chopper-stabilized

of

the Model

0.9

mV output for full-scale

5-8

through

412AIAR.

is

defined as a

for

all ranges

5-10,

OF

IV

OPERATION

4-9.

MODULATOR, AMPLIFIER, DEMODULATOR,

AN0

CHOPPER.

4-10. A

sets the Modulator/Demodulator frequency at line frequency. The Modulator output is an ac signal proportional stabilized at output synchronized with the Modulator signal Cathode Follower. This voltage is the same polarity as the input signal.

4-11.

SELECTION.

4-12.The Cathode Follower drives the Meter and the Amplifier Output. Polarity selection provides upscale meter reading for either polarity input. The Polarity switch is disabled in the

light-beam chopper driven by a synchronous motor

516

power

to

the Model

1

,111

of

1

.O

volt for a full-scale input. The Demodulator

is

converted to a steady dc, which

CATHODE FOLLOWER AND POLARITY

412A

input. The amplifier

by the feedback network, resulting in an

so

that the amplified ac

is

applied

gain

to

the

is

DC

OHMS

function.

is

RANOC

SELtCllOW

00

129-5

r

Figure

I

4-1.

Block Diagram

4-1

6

Section V

INSTRUMENT

DC

Voltage Standard

Variable Line Transformer

DC

Voltmeter

AC

Voltmeter

~ ~ ~~

Oscilloscope

TYPE

Table

5-1.

Test Equipment Required

REQUIRED CHARACTERISTICS

Range: Accuracy:

Current Rating:

Output Voltage:

Range: Resolution Input Resistance:

Range: to

Sensitivity:

(or

253 Vac)

0-300V

0.1%

1

V

to

300

:

10

mV

300

V

10

Ma

0.01

10

to

127

V

100

Vlcm

mA

Vac

Ma

hp- 738BR Voltmeter

Calibrator

1

Superior Electric

Powerstat 3PF116

(for

1

15

V line) 3PF216

V

(for 230

hp- 427A Voltmeter

hp-

427A Voltmeter

hp- 427A Voltmeter

hp

120B

line)

Oscilloscope

Model 412A

Precision Resistors

Oscillator

Resistance:

1

10

100

1K

10

30K

100K

300

K

1M

10

100

10

-~

~

Frequency : 60 Hz

Output:

K

M

5W

1W 1/2

W

IO

V peak

Accuracy

i

1.0%

2

1.0%

f

1.0%

f

1.0%

+,

1.0%

?

0.1%

2

0.1%

2

0.1%

2

0.1%

2

1.0%

2

1.0%

k

0.1%

:

Part Number:

-hP-

hP-

-hp-

-hP- 07574442 Daven Dale

Dale MFS-112

-hP

-hP-

-hp-

200CD Wide Range

Oscillator

08

1

I-OoFiO

07574346

0757.040

07574280

1

DAS-5

MF-I

06984 16 0698-5049

0733401

08

1

1-2475

1

7

Model 4 12A

Section

V

SECTION

MAINTENANCE

5-1.

INTRODUCTION.

5-2.

This section contains information necessary to maintain the kp- Model 412A/AR. The following paragraphs describe the Performance Checks, Calibration Procedures, Troubleshooting, and Servicing Procedures.

5-3.

REQUIRED TEST EQUIPMENT.

54.

Recommended test equipment for maintaining and

of

checking performance

5-1.

Test

instruments other than those recommended may

be

used if their specifications equal

characteristics.

55.

PERFORMANCE CHECKS.

5-6.

Use

the following procedures to verify proper operation of the Model 412A. The 412A and test equipment should otherwise specified. A Performance Test Card is provided at the end of this section for recording the performance of the Model 412A. The card may and used as a permanent record

or

of

a routine performance check. If the Model 412A does

not meet specifications at

5-1

to Paragraph

5-7.

METER

5-8.

The meter pointer should rest over the zero calibration mark when the instrument is at normal operating temperature, is turned off, and is in the normal operating position.

mechanical adjustment procedure outlined in Paragraph

8

before proceeding with the performance checks.

5-1

5-9.

Turn the Model 412A POWER switch ON. After a

5-minute warm-up period, the meter pointer should rest on

zero

when the input leads are shorted. If not, perform the

electrical zero adjustment outlined in Paragraph 5-22.

Operating the Model 412A/AR without grounding the third (power line ground) wire of the power cable will result in a zero offset of the meter and oscillation the printer.

5,

ZERO.

the Model 412A is listed in Table

or

exceed the required

be

operated at 115/230 Vac unless

be

removed from the manual

of

the incoming inspection

any

point in this procedure, refer

Adjustment and Calibration procedure.

If

the pointer is off

NOTE

zero,

perform the

of

V

5-10.

VOLTMETER ACCURACY CHECK.

a. A dc voltage standard and a variable line

for

transformer are required Model should be allowed a 30-minute warm-up period.

b. Connect 412A

line voltage switch (1 voltage being used. Turn 412A ON and allow 5-minute warm-up period.

c.

Set 412A FUNCTION to VOLTS, POLARITY to

738BR Voltmeter Calibrator is used, it

to

variable line transformer, and set

15/230)

+.

d. Connect VOLTS and COM leads to dc standard

out put.

e.

Check 412A indication against dc standard output

on

at full scale should be small division

When checking the Modcl 412A the .001 and off the dc standard output and note any 412A thermoelectric voltage. Add subtract the 412A reading.

f. Check 412A meter tracking

cardinal points on the meter scale. Maximum crror should be no greater than

polarity input.

g. Repeat step e on

and I27 volts

5-11.

MILLIAMMETER ACCURACY CHECK.

a. A dc voltage standard and the prccision rcsistors

listed in Table

b. Set 4 12A FUNCTION to MA. I’OLARITY to

each 412A range. Maximum error

no

greater than

on

top scale).

NOTE

.003

zero

as

necessary any offset from

.

1

V

(or

207 and 253 V).

5-2

rcquircd

this chcck.

to correspond to line

f

1%

of full scale (one

volt ranges, turn

offset due

on

the 1 V rang at

0.01

V

range at line voltages of

for

this chcck.

If

an -tip-

on

to or

all

with cithcr

103

+.

001

29-5

5-1

Section

V

Table

5-2.

Milliammeter Accuracy Check

Model

4

12A

DC

Standard

3

Range

.O

1

.03

.I .3

1

3

IO

30

c.

Connect Precision Resistor in series with MA lead

of

and positive side

412A

COM lead to dc standard negative output

terminal.

d. Perform checks listed in Table

dc standard output. Connect

output

IV

3v

10

v

30

V

100

v

300

v

300

V

300

V

300

V

300

V

5-2.

NOTE

It is not necessary

ranges.

1000, the current shunt does not change.

Only the voltage divider, checked in

On

to

check higher current

current ranges

10

through

Series

Resistance

I.00M

t

0.1%

1

.OOM

t

0.1%

1.00M~O.I%

1

.OOM

2

0.1%

I

.OOM 2 0.1%

1.00M?

300K

lOOK

30K

5-12.

0.1%

iO.l%

20.1%

2

to.]%

1/2

1

0.1%

5

Paragraph

shows simplified ammeter switching

circuits.

OHMMETER

a.

Set

b. Connect, in turn, resistor

100

between MA/OHMS and COM leads. With

appropriate RANGE setting, meter should indicate

between

W

W W

ACCURACY

FUNCTION

K, 1 M,

0.95

Model

5-10.

and

4

1

2A Reading

(

2%

of full scale)

1

.o

3

.O

1

.o

3

.O

1

.o

3

.O

1

-0

3

.O

1

.o

1

.O

(on

3

scale)

changes. Figure

CHECK.

selector

10

to

M,

and

1.05

in each case.

OHMS.

of

1,10,100,1

100

5-9

K,

M

ohms+I.O%

10

K,

DC

STANDARD

-hp-

MODEL

738BR

I

5-2

I

Figure

5-1.

Input Resistance Check

-hp-

MODEL

~

412A

001

29-5

J

Model 4

5-13.

i

h

12A

INPUT RESISTANCE

a.

Connect the Model 412A/AR, dc standard and

rnegolim resistor

b.

Set 412A

FUNCTION

CHECK.

as

shown

to

in

.Figure

VOLTS,

5-1.

POLARITY to

+.

c. Adjust

voltages listed in Table reading in each case verifies the input resistance where:

412A

Table

RANGE and dc standard output to

5-3.

A

correct meter

=

Eapplied

Ein

5-3.

Input Resistance Checks

412A

Reading

5.0

[

&&]

Meter

(?

1

%)

mV

1

412A

'

Resistance

IOMQ

Input

10

c. Set ac voltmeter FUNCTION

RANGE to

d. Adjust oscillator frequency to

output for an indication voltmeter. This corresponds noise signal at the

e. The 412A meter rcadingshould

division

5-15.

ADJUSTMENT AND CALIBRATION

5-16.

The following proccdures should bc pcrfornicd

it has been determined by the Performance Chccks outlincd

in

Paragraph

specifications.

5-17.

CABINET REMOVAL.

a. Disconnect power cord from powcr source.

IO

V.

on

upper scale)..

5-5

that the Model

412A

input.

412A/AR

to

60

of

to a IO

be

AC

Hz,

7.07

02

Section

and adjust

V

I%(l

V

VOLTS,

on

ac

pcak

;IC

minor

PROCEDURE.

only

if

docs

not

iiicct

22.5

mV

100

mV

9

5-14.

AC

c

D

REJECTION

a.

Connect the Model voltmeter as shown in Figure

b.

Set 412A FUNCTION to

+,

and RANGE to

OSCILLATOR

hp

200CD

90.9

0.95

CHECK.

412A/AK,

0.1

V.

mV

V

5-2.

VOLTS,

30

Ma

100

Ma

200

Ma

oscillator, and ac

POLARITY to

MODEL

-hp-

b.

On cabinet model, rcmovc two rctaining near center of rear panel. On rack modcl, rciiiovc

in

rcar

of

three retaining screws

c.

Slide instrument chassis forward

5-18.

MECHANICAL ADJUSTMENT

5-19.

If

mechanical zero over the zero calibration mark instrument is at normal opcrating tcmpcraturc, normal operating position, and turncd zero is not corrcct, perform thc following adjuslment procedure.

412A

of

mctcr is corrcct, pointcr rcsts

covcr.

out

OF

METER

on

thc nwtcr scalc wlicii

off.

scrcws

of

cabinct.

ZERO.

in

If

nicclianical

its

J

b

001

29-5

Figure

5-2.

AC

Rejection Check

5

-3

J

19

Section

V

10,

*7

3.

C

Model

4

I

2A

R46

METER

CAL

-

4

-

R126

HUM

BAL

CAL

R126

HUM

BAL

n

GAIN CAL

Figure

5-3.

Location

of

Adjustments

00

I

29-5

Model

4

12A

a. Turn 412A ON and allow a 20-minute warm-up

period. This normal operating tcniperaturc.

allows

meter movement

to

reach

5-22.

METER ELECTRICAL ZERO ADJUSTMENT.

NOTE

Section

V

30

b. Turn instrumcnt OFF and allow

capacitors

c.

Rotate mechanical zero-adjustment screw clockwise until meter pointer is to left of zero and moving upscale toward zero.

d. Continue to rotate adjustment screw clockwise

and stop when pointer If pointer overshoots zero, repeat steps

e. With pointer exactly on zero, rotate adjustment

screw counterclockwise approximately This frees adjustment screw from meter suspension. If pointer moves during this step, repeat steps

5-20.

HUM BALANCE ADJUSTMENT.

a. Turn

period.

b.

Set FUNCTION

c.

Connect oscilloscope to OUTPUT.

d. Adjust HUM BAL (R126, Figure

minimum line frequency is

8-1/3

to

discharge.

c

through e.

412A

ON and allow 5-minute warm-up

to

10

Hz

signal

Hz instead of

is

exactly over zero mark.

VOLTS.

on

oscilloscope. (If power

50

Hz, beat frequency will be

10

Hz.)

seconds for all

DC

AMPLIFIER

c

and d.

10

degrees.

5-3)

for

Meter electrical zero adjust circuit may not model instruments with serial number 424-14482 and below, or

41

serial number 424-1 5082 and below.

a. Turn 412A ON and allow

period.

b. Set FUNCTION c.

Short VOLTS probe

d. Adjust ZERO ADJ (R129) for zero dcflcction of

the meter pointer. Check the zcro adjustmcnt by switching POLARITY from adjusted properly, this action should produce a minimum amount of deflection.

5-23.

AMPLIFIER

B R AT1

0

CALI

a.

b.

c.

N

A

dc standard and a de voltmeter arc rcquircd for

these adjustments.

Connect 4 12A VOLTS probe and COM lcad standard output.

RANGE

Connect dc voltmeter betwccn dc standard output

(t)

and 412A

be

installed in 412A cabinet

2AR rack mount instruments with

a

30-minute warm-up

to

GAIN

VOLTS, RANGE

to

COM lead.

t

ADJUSTMENT AND METER

to

-

to

When zero

.

Set

FUNCTION

to

1

V,

POLARITY to

DC

AMPLIFIER OUTPUT liigli.

t.

in

.001.

to

is

to

dc

VOLTS,

NOTE

The Hum

the 120 minimum 10 With the VOLTS lead shorted COM

the 412A meter will show a minimum deflection when the Hum

Bal.

5-21.

CATHODE FOLLOWER BIAS ADJUSTMENT.

a.

Set

412A

beyond 1000).

b. Adjust rear panel BIAS

pointer approximately on zero. This adjustment is not critical, since reduced more switch is in any operating position.

00

129-5

Bal.

control docs not affect

Hz

ripple. Adjust only for

Iiz

(or

8-1/3

lead and POLARITY set

is

correctly adjusted.

RANGE

switch fully clockwise (one step

ADJ

any

deviation from zero is

than

100

times when the RANGE

Hz) signal.

to

(R116)

to

t,

set

meter

d.

Set

dc standard output to

e.

Adjust 412A GAIN indication on test voltmctcr. test voltmcter indicates calibration.

f. Adjust METER CAL (R46) to sct 412A meter

1.0

pointer on voltmctcr.

g.

Chcck 4l2A calibration at full scalc on all ranges as outlined error morc than

to

bring

all

5-24.

OHMMETER ADJUSTMENT.

a. Set 412A FUNCTION to OIIMS, ItANGIi to

Make ccrtain connected through wmc cxtcrnal rcsistancc.

on top scale. Disconnect test

in

Paragraph

I%,

readings within

MA/OlIMS

+I

CAL

1%

5-10.

rcadjusl

f

1

and (:OM

V.

(RI

19)

A

10

mV rcading

crror in 4 12A gain

If

any rcading

GAIN

CAL

X.

lcads

for zcro

on

is

in

(It1

19)

XI

K.

are not

5-5

Section

V

Model 4 12A

b. Adjust rear panel OHMS ADS (R36) for meter

indication

(corresponding to

1.0

on upper

of

aD

scale).

525.

TROUBLESHOOTING.

5-26. When the Model 412A/AR operates improperly, first

to

adjust and calibrate it according

5-15.

If

in Paragraph

calibration

the procedures outlined

is

not possible, procecd

with the troubleshooting steps.

CONTAMINATION OR FINGERPRINTS ON THE RANGE

OR

SWITCH MOUNTED

THE COMPONENTS

ON

THE RANGE SWITCH MAY REDUCE ACCURACY OF INSTRUMENT.

5-27.

FRONT

5-28.

If the malfunction is common

PANEL INDICATIONS.

to

all

ranges and functions, the trouble may be in the amplifier or power supply areas. If the instrument operates improperly on only

or

one range

function, the trouble

switching section

5-29.

POWER SUPPLY

or

input cables.

AND

AMPLIFIER CHECKS.

is

probably in the

5-5.

Table

Tube Iteplaced

VI01 (12AX7) Amplifier

V102 (6AU8) Amplifier/

Cathode Follower

V103 (6x4) Rectifier

V104 (OA2) Regulator

VI05 (OB2) Regulator

5-33.

MODULATOR

a.

An oscilloscope and

CHECK.

for this test.

b.

Disconnect 412A from power source and remove cabinet.

c.

Remove VlOl and reconnect 412A to power

source.

a

d. Connect

(rear panel

clip lead

BIAS

VOLTS input cable (terminal

Tube Iteplacement

Adjustment

Bal.

Huni

Par.

Gain Cal. Par.

Bias

Adj.

Par.

Cal.

Cain

Par.

None

Ohms Adj.

Par.

-71

a

10

Maresistor are required

from

the center arm

ADJ) to the termination

4

in Figure

5-20

5-23

5-21

5-23

5-24

of

5-7).

R116

of

the

5-30.

Check power supply voltages at points listed in Table

5-4.

Voltages are measured with respect

(A).

Figure

7-2

shows the location

Check Point

53

1.

Tubes are a coinmon source

to

circuit common

of

components.

Voltage

of

trouble and are most

easily checked by substitution. Following replacement

of

in

210%.

particular tube, iiiake the adjustrneiits indicated

5-5.

5-32.

Additional

by

made

of

Note

cliecking

tlic

sclrwutic diagram.

I1

in

checks

voltages shown

Paragraph

of

amplifier operation niay be

Be

sure

7-2.

Allow 3 tolerance

on

the amplifier section

to

observe conditions

of

a

Table

in

e. Set 412A FUNCTION to VOLTS, RANGE to

.001.

f.

Set oscilloscope input to

g.

Connect a

10

DC.

Mfi

resistor in series with oscilloscope vertical input. Using a clip lead, connect resistor

junction

of

RlOl and ClOl

to

(input circuit board, Figure 54). Connect oscilloscope common to 412A COM lead. Set

to

0.2

Vertical Sensitivity

I

Figure

54.

Input

V/cm.

Circuit

Board

5-6

00 1 29-5

Model 4 12A

Section

V

h. Turn 412A ON and allow 30-second warm-up

period. Observe de voltage amplitude on

oscilloscope.

i. Move oscilloscopc input (with series resistor) to

Modulator output at junction of green lead from

Modulator and C104

j.

Waveform should be similar

Figure

5-5.

Peak-to-peak amplitude should be approximately equal h. Signal frequency sliould be

(0.01

Microfarads).

to

that shown in

to

dc voltage observed in step

5/6

power line

frequency.

k. If waveform is not satisfactory, check chopper

motor and assembly or Modulator and input circuit as indicated by deficiency in waveform.

p-20

MSEC-

--)1

d. Remove four screws holding light-beam chopper

assembly. It is not necessary to disconnect wires.

e. Spread grip rings on Modulator light rods and slide

rods out

of

Modulator block.

f. Remove four screws holding modulator assembly

to

chassis.

NOTE

Be

sure

to

seat the four insulating shoulder washers in mounting holcs when replacing the assembly.

g.

Lift out Modulator assembly. If it is necessary to replace Modulator block asscmbly only, rcmovc four screws holding printed circuit board Note color and location

of

wircs between block

and printed circuit board before disconnccting.

5-36.

DEMODULATOR

a.

Disconnect 412A from powcr sourcc and removc

CHECK.

cabinet.

to

block.

Figure

55.

Modulator Waveform

5-34.

MODULATOR

5-35.

The photoconductor cells in the Modulator

(VllOA/B) are not separately replaceable.

REPLACEMENT.

If

a

cell

is defective, the Modulator block assembly should be replaced, using the following procedure.

a. Disconnect 412A from power source and remove

cabinet.

CONTAMlNATION OR

ON

FINGERPRINTS

THE RANGE

SWITCH OR COMPONENTS

ON

MOUNTED

THE RANGE SWlTCII MAY KEDUCE ACCURACY

OF

THE

INSTRUMENT.

b.

In 41 2A cabinet model, remove side shield.

c.

Note and record color code of wires before removing from Modulator assembly printed circuit board.

b. Remove V102 (on Amplifier Assembly).

c.

On

iight-beam chopper assembly, rcmove uppcr lamp nearest front of instrument. This illuminates

d. Connect a

VI

1

I

A.

1.0

microfarad capacitor across input

lamp

terminals of test ohmmeter.

e. Connect test ohmmeter common lead

Demodulator terminal with pinklorange wirc. Figure

56.

f. Connect other

test

ohmmeter lcad to tcrminal

to

Sec

with whitelorange wire.

g.

Connect 412A

h. Resistance indicated on

to

power source and turn

test

ohmmeter

ON.

should

bc

.

I

to 2 megohms.

i. Turn

j.

41

2A

OFF.

Replace lamp in light-beam chopper and remove upper lamp nearest rear of instrument. This lamp

VI

illuminates

I 1 B.

k. Connect test ohmmeter common lcad to

Demodulator terminal with brownlorange wirc.

001

29-5

5

-7

.

,

.

. -.

.

,

.

._...

.

..

-

..

.,

.

. --*w

”-

b

Section

V

I.

Connect other test ohmmeter lead to terminal

with whitelorange wire.

Model 4 12A

OR FINGERPRINTS MAY KEDUCE ACCURACY OF INSTRUMENT. IN ADDITION, LOW ROSIN CONTENT

m.Turn412AON.

SOLDER SHOULD BE USED WHEN

REPLACING COMPONENTS. USE A

I

MINIMUM OF HEAT WHEN SOLDERING, AND REMOVE TRACES

OF

FLUX

FROM CONNECTIONS. IF NECESSARY, RANGE SWITCH MAY BE CLEANED USING A SOLUTION OF

b

Iy

n. Resistance indicated on test ohmmeter should be

to 2 megohms.

0.

Turn

41

2A OFF and replace lamp and

5-37. DEMODULATOR REPLACEMENT.

V102.

MILD DETERGENT AND WARM

5-38.

The photoconductors in the Demodulator are not

cell

separately replaceable. If a

Demodulator assembly should

is defective, the

be

replaced, using the

WATER. RINSE THOROUGHLY IN DISTILLED WATER AND

DRY

IMMEDIATELY.

following procedure:

a. Disconnect instrument from power source and

remove cabinet.

b.

Disconnect the three wires

5-6

assembly. Figure

shows wire

to

Demodulator

color

codes for

both cabinet (4 12A) and rack (4 12AR) models.

c. Remove four screws holding light-beam chopper.

is

not necessary to disconnect wires.

It

540.If

function, trouble may be in the switching circuits. Either a component through

function switching, and may be used to isolate the trouble.

For example, if the instrument operates properly on all voltage ranges except contacts may be defective. Figure components mountcd on the

the malfunction is peculiar to one range

or

switch contact may be defective. Figures

5-10

show simplified schematics of range and

.003;

R1, R9,

rmgc

or

the associated switch

7-3

identifies the

switch.

or

58

5-41.

d.

Remove nuts from four screws holding

.I

Demodulator assembly and remove assembly from

ADJUSTMENT

COMPONENTS.

OF

FACTORY

SELECTED

instrument.

542. R34*.

5-39. SWITCH CHECKS.

5-43.

The value of

R34*

is selected to bring the OHMS ADJ potentiometer within the proper range, and is dependent upon the power supply voltage and the value

CLEAN RUBBER GLOVES SHOULD

BE WORN WHEN WORKING ON

THE

RANGE SWITCH. CONTAMINATION

6

resistors in the ohmmeter circuit. Replacement should not be necessary unless V104 has been replaced

the range switch components have been changed.

VI

of

TO

Cl13

TO AND

TO

RI

16

other

R34*

If

C114

Rll7

or

the

412A-8-50160

(CABINET

MODEL)

5-8

412A

Figure

56

Demodulator Assembly

412AR

(RACK

MODEL)

00

1

29-5

Section

V

Model

4

12A

cow

R48

MI

SZA

S2A

SIC

.OOlV

SIC

RIO

9.00M

RANGE

RI

SIE

2.8451

t2

8

AMPLIFIER

520

TO

COM

R48

52A

S2A

SIC

.03V

R4

.IV

RANGE

R3

R7

RANGE

R3

SIE

RII

TO

853.4K

SIE

853.4K

R19

S28

AMPLIFIER

S28

TO

coMw’

-I’

.003V

R48 &?A

/$t

7

A

-

SIC

RANGE

R2

9

e.tW

9

SIE

13

I1

-1

528

8

AMPLIF

TO

I

IER

SZA

SIC

R3TORB

IO

.i:

30

300

Ioo4

1000

d

R7

RI1

264K

R19

’!%

190

SIE

6

46.W

7---

36.95K

S28

I3

I1

8

D

.I

FlER

.OlV

RANGE

8.:.

c

¶om34

Figure

5-10

.3

TO

5-8.

Simplified Schematic, Voltmeter Switching

IOOOV

RANGES

00

1

29-5

5

Model

4

12A

Section

V

a

b

S2A

SIB

.003

.3

3

10

R50

R40

2

1.6

I

S2A

SlD

9.00M

i

-f

SI€

It

I

12,16

lo

S2B

8

AMPLIFIER

t:

.001

TO

IOMA RANGES

S2A

a

*

d7

S2bl

S2A

0

S2A

0

7

-

SIB

R3T

TOR44

999.9

--

I

R3TTOR44 RSO

999.9

-*

R45

.IO0

R37mR44

9 999.9

R45

.IO0

R37

TOR44

999.9

R45

.IO0

RSO

IM

RSO

IM

RSO

IM

IO

S2A

IO

S2A

10

S2A

II

I1

II

St0

II

6

-7

SI0

6

s

SI0

8

A

"

SID

6

v

9

8

?

IO

RI

6.155M

R2

B.IOH

R3

2B.M

R4

7O.W

IO

1

9

46.3K

A3

2RIM

SI€

12.16

IO

SI€

12.16

10

v

-1

R7

8

--

1

Io.'

S2B

AM

528

8

SIC

12.16

SI€

I

R7

B53.4K

PLl

,J

12.16

m

TO

IO

-1

I

FlER

s20

0

10

-1

928

30MA RANGE

100MA

to

a

RANGE

300

MA

RANGE

1000

RANGE

MA

Figure

a

00129-5

5-9.

Simplified Schematic,

Ammeter

Switching

5-1

1

.~

--

/__I

f

3

Model

4

Section

e

V

R20.21

RSO

TO

R33

12A

4

8

I

COW

75

MA

co

SZA SIA

as

R49 926

IM

312

I

R34

123U

I

--.-.-

R29

0.9

s.13

SI0

2

R2

9

(UOM

-

1-1

R8

WOK

13

R35

2700

SIF

R36

so00

+BOV

XI

528

8

9

a

to

AMPLIFIER

RANGE

,J

R2l

R10

TO

R33

10.19K

XI0

RANGE

1

TO

AMPLIFIER

J

*

S2A SIA R20.21

86

8

A49

IM

310

6

SIA R3

I

2 198.IM

#.

r*M

R25

I.0OM

TOR6

-

.:

;.

-

R30

.47

R

99.0

*..

7.1

1.12

7198K

I

CI

I

E

-

7

*:R29

:)0.9

R

34

123K

-

1-1

RIS

.

SIF

48

TO

R19

R35

2700

528

98

R36

m

TO

AMPLIFIER

I

XI00

XIOOM

THRU

RANGES

Figure

e

5-1

2

5-10.

Simplified Schematic, Ohmmeter

Switching

PERFORMANCE TEST

CARD

Ilewlett-l%ackard

Vacuum Tube Voltmeter Serial

No.--

Model

4

PARAGRAPH

5

-8

5

-9

5-10

I2A/AI<

DESCRlPTlON

Meter Zero

Mechanical Electrical

Voltmeter Accuracy Check

Range

:

.oo

1

.003

.o

1

.03

.1

.3

1

3

10

30

100

300

1000

Tests Perforincd

CHECK

OK OK

.

Reading

by

Date

Limits

,+

1%

2

1%

,+

1%

5

1%

s

1%

f

1%

2

1%

t

1%

,c

1%

2

1%

2

1%

2

1%

r

1%

5-1

1

I-

5-1

2

Io

Milliammeter Accuracy Check

Range

:

.oo

1

.003

.o

1

.03

.1

.3

I

3

10

30

Ohmmeter Accuracy Check

Range

:

XI

XI0

XlOO

X1

K

XlOK

XlOOK

X1

M

2

-

'f=

2

f

r

2

f

+,

0.9s

0.95

2% 2%

2% 2% 2%

22

2% 2%

2%

to to to

to

I

.os

I

.os

1

.OS

1

.OS

I

.OS

1

.OS

1

.OS

.

_.

.

...

"

,.._

. ~ _.

_,

.

.~

..

~

.-....-

..-

--

-

..-

_.-

PARAGRAPH

5-1

3

5-14

PERFORMANCE

TEST

DESCRIPTION

Ohmmeter Accuracy Check

Range

:

XlOM

X

1

OOM

Input Resistance Check

Range

:

.o

1

.03

.I

1

AC

Rejection Check

CARD (Cont'd)

CHECK

Reading

Limits

0.95

0

to

f.

1%

t

1%

i

1%

2

1%

+I%

1.05

c

Model 4 12A

Section

VI

SECTION

REPLACEABLE

INTR

0

D

UCTlO

6-1.

6-2.

This section contains information for ordering

replacement parts. Table

of

their reference designators arid indicates the description, hp- part number of each part, together with any applicable notes, and provides the following:

a.

Total quantity used in the instrument (TQ column). The first time the part number appears.

b. Description

below

c. Typical manufacturer of the part in a fivedigit

code. (See Appendix

d. Manufacturer's part numbcr.

N.

6-1

lists parts in alphameric order

total

quantity of a part is given the

of

the part. (See list

of

abbreviations

.)

A

for list

of

manufacturers.)

VI

PARTS

6-3.

Miscellaneous parts are listed at the end of Table

6-4.

0

R

D

E

R

ING

INFO

RMATIO

6-5.

To obtain replacement parts, address order

N.

to your local Hewlett-Packad Field Office. (See Appendix

B

for list of office locations.) Identify parts by their Hewlett-l'ackard part numbers. Include instrument model and serial numbers,

6-6.

NON-LISTED

6-7.

To obtain a part that is not listed, include:

a.

Instrument model number.

b.

Instrument serial number.

c.

Dcscription of the part.

PARTS.

d. Function and location of thc part.

or

inquiry

6-1.

A =aswmhly

B

=

motor

=

BT

C

CR

DL =delay llne

DS

E

At? A1

A

Au

C

cer coef com comp conn

dep

DPDT

DPST

elect

encap

P

FET fxd

GaAS

GHz

nd

Ge

grd

H

Hb'

Hz

.'"

battery

=

ca[mritor

=

dicdc

=lamp

=

misc electronic part

=

silver

=

aluminum

=

ampere

=

gold

=

capacitor

=

ceramic

=

coefficient

=

common

=

composition

=

connection

=

deposited

=

double-pole double-

throw

=

double-pole single-

throw

=

electrolytic

=

encapsulated

=

farad

=

field effect transistor

=

fixed

=

bmllium arsenide

=

gigahertz

=

guard (ed)

=

germanium

=

ground (ed)

=

hen* (ies)

=

merrury

=

hertz (cycle

second)

'

(9)

(s)

DESIGNATORS

F

=

FL

HR 1c

J

K

L

M

ID

impg = impregnated incd

ins kn

L

lin loft

m

mA

MHz Mn met

mfr

mtg mV

F

=

hertz

PV my =Mylar

n~

NC Ne =neon NO

(8)

per

NPO

@

fusc

=

filter

=

heater

=

integrated circuit

=jack

=

relay

=

inductor

=

meter

=

inside diameter ns

=

incandescent

=

insulation (ea)

=

kilohm

(s)

=

taper

10''

film

=

10-8

(8)

l0+3

=

(s)

lo''

(s)

10"

106

=

hertz

=

IO-'

10''

=

kfio,,,,rh

=

inductor

=

linear

=

logarithmlc taper

=

mfill

=

milliampere

amperes

=

megahertz

=

megohm6)

flm

=

metal

=

manufacturer

=

mounting

=

millivolt

=

micro

=

microvolt

@

=

nanoampere

amperes

=

normally closed

=

normally open

=

negative positive zero

(zero temperature coefficient)

Dupont de Nemours

(s)

=

ohms

10''

her&

ohms

UP

P

Q

FR

RT =thermistor

S

T =transformer

ABBREVIATIONS

nsr

0

OM

OD

P

PC

volts

R Rh

rms

rot

Se sect Si

=

mechanical

=

plug

=

transistor

=

transistor-diode

=

resistor

=

switch

=

nanosecond

seconds

=

not separately replace-

able

=

ohm

=

order

=

outside diameter

=

peak

=printed circuit

=

picoZarad

farads

=

peak inverse voltage

=

part

-=

position

=

polystyrene

=

potentiometer

=

peak-to-peak

=parts per milllun

=

precision (temperature

ocx?fficient. long term stability. and/or tolerance)

=

resistor

=

rhodium

=

root-mean-square

=

rotary

=

srlenium

=

section

=

silicon

(8)

by

description

of

(8)

(s)

part

(8)

=

lo-''

TC

=

V

W X

XDS

XF

Z

sl

SPDT SPST

Ta =tantalum

TC

TLO? tog

IO1

trim TSTR

V

vacw

var

vdcw

W

w/ =with wiv w/o =without

ww

*

**

thcrmoronlplc

=

vacuum

hulb. photocrll. ctv.

=

ra1,le

=

socket

=

lampholder

=

fuseholder

=

nctwork

=

slide

=

slngle-pole double-

throw

=

single-pole single-

throw

=

temperature cwfficlent

=

titanlum dioxide

=toggle =tolerance

=

trimmer

=transistor

=

volt

(8)

=

alternating current

working voltage

=

variable

=

direct current working

voltage

=watt

(a)

=

working inverse vultagc

=

wirewound

=

optimum value selected

at factory. averagc value shown (part may

be

omitted)

=

no standard type num-

ber

assigned (seleetud

or

special type)

IUIW.

tnwn

00

1

29-5

Section

VI

REFERENCE DESIGNATOR

81 thru 8100 8101

c1

c2

ClOO

C3 thru

ClOl

thru C103

C104

Cl05A/B C106 C107 C108. c109 CllO

Clll c112 C113 C114 C115.Cl16

C117 Cll8 C119A/B

CAlOO

CRlOl

CR102, CR103 DSlOO

OS101 thru DS105

FlOl

J1Ol

M1 P101 Rl

R2

A3 R4

R5,

R6

R7

R8

R9 R10 Rl1

R12 R13 R14 R15

R16

R17 R18

R19

R20

R21

R22

R23

R24

R25

R26

R28

R27.

R29

-hp-

PART

31400013 01704019

0

1804 105

0

160-264 1

0170.0029 01804086

01404151 01800033 01500012 0180-0033

01604015 01504024 0150-0012 01704003 0160-0015

0160.0019 01804054 01 50-01 19

19024048 19014025

2140.0012

2110-0016 2110-0017

1510-0006 151 04007 03404087 0340-009 1

1120-0305 8120-0050 07304128

0730.0134

0730.0149 0733-0014

0730.0150 07274192

0727.0262 073041 17 0730-0139 0727-0231

0727-0239

0727.0215 0727-0188 0727-0164

0727.0130

0727.0 106

0727.0070 0727-005 1

412A.266

0727.0039 0727-0095

0727.0152 0727-0204

0727.0274 0730-0144

0733.0017

412A.260

NO.

Table

6-1.

-

Replaceable

TQ

-

Not assigned

1

Motor: synchronous type

1

C:

fxd

my

0.01

1

C:

fxd semi.polarized 50 microfarads

Not assigned

1

C:

1 1

1

2

3

1

I

1

2

5

1

2

1 1 1

1

1 1 1 1

2

1

1 1

1

1 1

1 1 1 1 1

1 1 1 3 1

1 1

fxd poly 0.1 microfarads 10%

C:

fxd poly 0.01 microfarads 10%

C:

fxd

C:

fxd mica

C:

fxd

C: fxd cw 0.01 microfarads

C:

fxd AI

C: fxd paper 0.47 microfarads 10%

C: fxd cer

C: fxd cer 0.01 microfarads E: fxd C: fxd papw 0.47 microfarads 10%

C: fxd paper 0.01 microfarads

C:

fxd AI

C: fxd cer Not

assigned Oiode: Si Diode:

Not

assigned

Lamp: miniature

Fuse: cartridge

Fuse:

Binding post assembly: black Binding post assembly: red no solder turret Insulator: BP triple Insulator:

Meter

Power cord

R:

fxd C flm 6.155 megohms

R:

fxd C flm 8.1 megohms0.5% 1

R:

fxd C flm

R:

fxd C flm 70 megohms

R:

fxd C flm 50 megohms0.5% 1

R:

fxd C flm 46.3 kilohms0.5%

R:

txd C flm 900 kilohms0.5% 1/2

R:

fxd C flm 2.845

R:

fwdCflm9megohmr0.5%1

R.

fxd C flm 284 kilohms 0.5% 112

R:

lxd C flm 389.5 kilohms 0.5% 1/2

R:

fxd C flm 123 kilohms0.5% 1/2

R:

fxd C flm 38.95 kilohms

R:

fxd C flm 12.3 kilohms

R:

fxd C flm 3.895 kilohms0.5% 1/2

R:

fxd C flm 1230 ohms

A:

fxd C flm 389 olirns0.5% 112

A:

fxd C flm 180 ohmsOd% 1/2

R:

fxd w 9 ohms

R:

fxd

R:

fxd C flm 900 ohms 1% 1/2

R:

fxd C flm 9000

R:

fxd C flm 90 kilohrns 1%

R:

fxd C flm 1 megohm 1% 1/2

R:

fxd

R:

fxd C flm 100 megohms 1% 2

R.

fxdw0.900ohms

microfarads 5%

AI

elect 2 sect

820

pF

AI

elect 50 microfarads 6 vdcw+lOO% -10%

elect

50 microfarads 6 vdcw +loo% -10%

0.02

microfarads

my

0.051 microfarads 10%

elect

1

sect 1.5 k microfarads 10 vdcw

2

sect 0.01 microfarads/sect

EIA

15 A 200 piv

Si

1OOpiv 12

2

0.6

BP

triple

28.1

flm

3795 ohms

A

megohms

cartridge 0.4 A slow-blow (for 230 V operation)

C

ohms

C

Hm

10.52 megohms

Parts

DESCRIPTION

~~~

6.3

Vac

200

vdcw

25

vdcw

50

vdcw

50

vdcw

20

microfaradslsect 450 vdcw

2%

20%

1000 vdcw

200

-20%

1000 vdcw

200

5%

600

no

solder turret

0.5%

1

W

1

W

1/2

W

0.5%

1

W

1/2

W

112 W

W

1/2

W

1% 1 W

W

vdm 600 vdcw

vdcw

250

W

vdcw

+EO%

20%

pF

100 mA

slow-blow (for 115 V operation)

0.5%

0.5% 2 W

0.5%

1% 1

1

MFR.

-

73061

8441 1 56289

56289 56289

56289 72136 56289 56289 56289

56289 91418 56289 00853 56289

56289 56289 71590

04713 07263

24455

71400 75915

-hp.hp.

kP-

-hp.

-hp70903 19701

19701 03888 03888 19701

19701 19701 19701 19701 19701

19701 19701 19701 19701

19701 19701

.hp-

19701

91637

19701 19701 19701 19701

03888

.hp-

Model

MFR.

PARTNO.

610 (6.3

V)

620s S97441

Special 2758

114P1039R5S2

032477

ROM15F821G3S 300506GO06C82-DSM 29C214A3-H-1038 300506G006C82-OSM

109P47492

8-OZGMV

29C2 14A3.H-1038 33102152 109P47492

160P10356 D32495 DA171CB

1N321U

F02387

No.

12

MD

L6/10

313400

CS.994 1 /PH .1511

A5

DC1 DClR5 PTlOOO

PT2000

R5

DC1 MF7C

MF7C DClR5

DClR5

MF7C MF7C

MF7C Mf7C MF7C MF7C

Mf7C MF7C MF7C

MF7C ocs-1/2-15

CF1/2 CF1/2 MF7C DC-1

PT20OO

412A

obd obd

obd obd obd obd obd

obd obd obd obd

Obd

ob11

obd obd

obd

obd obd obd

obd

6.2

00129.5

Model 412A

Section

VI

REFEREXCE JIESIGNATOR

R30 R31 R32 R33 R34’

R35 R36 R37 R38 R39

R40

1

R4 R42 R43 R44

R45

R46

R47* R48 R49. R50

RlOO

R51 thru

RlOl

R102 R103 R104

R105 R106 R107 R108 R109

RllO

Rlll

R112 R113 R114

R115 R116 R117 Rll8 R119

R120 A121 R122 R123 R124

R125 A126 R127. R128 A129 ~i3n

R131 R132

s1

s2

s3

S4

thrii SlO0 SlUl s102

T1 lliru TlOO Tt01

~

-hp-

PAR?’

081 3-001

0698.0001 0727-0040

081

i.no117

0690-2721 21 00.0011 0727-0086 0727-0056

0727.0035

412A.26H 412A26F 412A.26E 412A-26C 412A.266

412A.26A

2100-0021

0727-0274

06874741 0686-1045 0687-1821 07570178

06874751 0687-1051 0687-1031 06872261 0687-1051

06874731 0687-2751

0687.1021

0687.1041 0687-8241

0687-3331

2100-0009 0687-2751 0687-1031

2100-1436 0727-0209

0687.1821 0690-1211 0690-5611 081 1.1512

081 1-1867

2

100-0078 06844741 2100-1567 0683-1045

06834325 07570156

412A.19A 412A.198

3100-0183 31nu.oi84

3101-000 1 3101-0033

91004238 9 100-002 1

NO

9

TQ

DESCRIPTION

-

1

R:

fxd

ww

R:

1

A:

1

R:

1

Factory Selected

R:

1

R:

1

R:

1

R:

1

A:

1

R:

1

R:

1

R:

1

R:

1

R:

1

R:

1

R:

1

Factory Selected Value.

nsr; part

R:

Not assigned

R:

1

R:

1

2

A:

1

R:

1

2

R:

2

R:

1

R: R:

R:

1

2

R:

1

R: R:

1

R:

1

A:

1

A:

1

R:

1

R:

1

R:

R: R:

1

R:

I

R:

1

A:

1

R:

1

2

R:

1

R:

1

R:

A:

1

R:

1

Assembly: range switch for cabinet model (include S2, S3)

1

Assembly: range switch for rack model (include

1

Switch: lever

1

Switch: lever 1 sect

1

Not

Switch: toggle

1

Switch: slide

1

Not

Transformer: power (used in instrumentsswial number

1

Transformer: power

1

0.47 ohms fxd comp 4.7 fxd C flm 94.8 ohms 1% 112 fxd w 10

fxd comp vir comp lin 5000 ohms fxd

C

flm

fxdCflm216ohms0.5%1/2W fxd C flm 68.4

fxdww21.6ohms fxd 6.84 fxd

ww

2.16 ohms fxd

ww

0.684 ohms lxd wwO.216 ohms

fxd

ww

0.1 ohms var

ww

lin

of

voltage probe assembly

fxd C flm 1 megohm 1% 1/2 W

fxd comp 470 kilohms fxd comp 100 kilohms5% 112 fxd comp fxd met

fxd comp 4.7 megohms 10% 1/2 fxd comp 1 megohm 10% fxd comp 10 kilohms fxd comp fxd comp 1 megohm lU% 112

fxd comp 47 kilohms fxd comp 2.7 megohms fxd comp fxd comp lxd comp

fxd comp 33 kilohms 10% 1/2 var comp fxd comp 2.7 megohms 10% 112 fxd comp 10 kilohms 10% 112 var comp

fxd C flm 108 kilohms 1% 112 fxd comp 1800 ohms 10% 112 W fxd comp 120 ohms 10% 1 fxd comp 560 ohms 10% 1 W fxd

ww

4000 ohms 5%

fxd

ww

var comp lin 500 ohms 30% 3/10 fxd comp 470 kilohms 10% 1/2 var

ww

tin

fxd comp 100 kilohms5K 1/4 fxd comp 4300 ohms

fxd met

assigned

316.08283 and above) 301-08282 and below)

1%

ohms

5% 1/2

kilohms 1% 5 W

Value.

See

2700

ohms 10% 1 W

684 ohms0.5%

ohmsO.5%

ohms

100

ohms 20%

See

I800

ohms

llm

100 ohms

22

megohms 10% 112

1000

ohms

100

kilohms 10% 112

820

kilohms 10%

25

kilohms 20% 1/3 W

tin

10 kilohms 30% 1/8

15

kilohms

5%

10 kilohms 10%

flm

1.5

megohms

2

sect 3 position

2

position

SPST

250 V 3 A

OPOT

(used

1/2

W

w

W

Paragraph

20%

112

1/2

W

1/2 W

2

W

Paragraph 541.

10%

1/2

W

10%

1/2

W

1%

1/4

W

1/2

W

10%

112 W

W

10%

In

W

10%

112

10% 112

W

1/2 W

W

5

W

5

W

2

W

5%

1/4

W

I%

1R

in instrumentsserial number

-

W

5-41.

S2,

S3)

-

MFIZ.

.hp01121 19701 91637

01121 11 237 19701 19701 19701

-hp-

-hp *hp.

-hp.

-hp. .hp

11236

19701

01121 01121 01121

19701

01121 01121 01121 01121 01121

01121

11237 01121 01121 7 1450

19701 01121 01121 01 121

56289 56289

11237 01121 71450 01121

01121 75042

-hp

-hP.

76854

76854 04009

42 190

-hp

.hp-

MFR.

PARTNO.

EB47G5 MF7C RS-5

G82721 Type 45 MF7C MF7C MF7C

Type 112

MF7C

E84741 E81045 E61821

T-0

MF6C E84751

E61051 E81031 E62261 E61051

E64731 E82751 E61021 EB1041 E88241

E83331 Type 45 E82751 E81031

aszoo

MF7C E61821 GI31211 GI35611

243E 243E

Model

70

E64741 117 CB1045

C84325

T-0

CEC

190503.187-N2C 189777-187-K

80994.H 4633

1

obd

00

129.5

6-3

Ssction VI

REFERENCE DESIGNATOR

V1 thru VlOO VlOl v102 V103 V104 V105

-hp-

PART

NO.

1932-0030

1933.0007

1930-00 16

1940-0004

1940.0007

03704035 03704081

00412-62101

4 12A-16A 412A-161: 41 2A-2 1

E

412A-21F 412A-238

412A37A 412A-378

412A-95A

412A-30A 412A-58C

412A65A

412A.97A

1220.0009 14004084

14004088 1400-0089

14504022

Table

6-1.

-

TQ

Replaceable Parts

DESCRIPTION

(Cont'd)

-

Not assigned

1

Tube: electron 12AX7

1

Tube: electron 6AU8

1

Tube: electron 6x4

1

Tube: electron OA2

1

Tube: electron OB2

MISCELLANEOUS

1

Knob: range switch

1

Knob: function witchlpolarity switch

1

Probe and cable aaembly: voltage (include R48)

of

parts

for

For breakdown

see

assembly,

1

Cable: Modulator Cable: Modulator (for 412AR rack model only)

1 1

Cable assembly: Common

1

Cable assembly: OhmMa

1

Demodulator block assembly: (includes VlllAl8, R127. R128) Light rod: modulator for Model 412A

2 2

Light rod: modulator for Model 412AR

1

Modulator block assembly: (includes VllOAlE)

1

Modulator asrembly: (includes 412A48C. V1 lOAl8)

1

lnput circuit assembly: (doer not include V1 lOAlBI Amplifier assembly

1 1

Chopper assembly: (includes motor, lamps and leads) Tube: shield

1

Fuseholder: extractor

2

Alligator clip Insulator: alligator clip

1

Lampholder:

5

Figure 6-3.

for

voltage probe and cable

(for

412A cabinet model only)

post

type

2

pin lamp

-

MFR.

80131 80131 80131 80131 80131

hP.

hP-

-hP

-hp.

-hp. .hp.

-hp.

-h

p

-hP

JlP

hP

.hp-

hP-

-hp-

-hp71785

75915 75915 75915

72765

MFR.

12AX7 6AU8 6x4 OA2 OB2

12627

342014 obd

obd

2020AE

PARTNO.

64

00129-5

Model

412A

RE FER ENCE

DESIGNATOR I PART NO.

MP1

MP2

MP3

MP4 MP5 MP6

MP7

MP8

MP9 MPlO MPll MP12

-h11-

~-

50600698

10-000

25 412A-1C

0510-0189

412A47A

25500007

25300010 412A-1A 412A-18 412A.2

2520-0009

0340-0089

50200653

23600142

14500020

412A83A 412A-12C 412A-12A 412A-6A

23600195 30500066 2190-0007

Section

VI

Table

6-1.

Replacea

TQ

-

1

Cabinet assembly

2

Screw:

1

Chassis

2

Nut: retaining

1

Support:

1

Screw:

1

Screw:

1

Chassis: main deck

1

Chassis: side deck

1

Panel: front

2

Screw:

6

Insulator

1

Bezel

6

Screw:

1

Jewel:

3

Boot: cable

1

Bracket: cable

1

Bracket: cable

1

Shield: input circuit

3

!hew:

3

Washer:

3

Lockwasher:

8-32 x 5/8"

rear

deck

chassis

8-32

binding head

8.32

flat head

8-32

round head

6-32 x 114"

indicator

6-32 x 5/16"

No.

6

No.

le

Parts

DESCRIPTION

8-32

flat

6

internal tooth

(Cont'd)

-

MFR.

-

MFR.

~~

PARTNO.

MP2

MP3

'

Mr

MP?

00129-5

Figure

6-1.

Location

of

Mechanical

Parts.

Cabinet Model

MP8

..

*-

6.5

n

Section

VI

b

Table

6-1.

1

rs

REFERENCE

-hp-

DESIGNATOR I PART

MP13

MP14

MP15 MP16 MP17

MP18

MP19 MP20

412A44R

25100001

412A-1E

051 0-0189 412A-1G 412A-10 412A-60

2360-0228 24200001

412A-2R

25200009 03400089 30500055 21900017 25800005

14500022

412A.lF

25300006 03404089 3050-0055 2190001 25800005

2390.0010 21900006

3050-0066

14000031 2420-0001 0380-0018 04000010

NO.

7

TQ

1

Du~tcoverarsembly

3

Screw: 8-32

I

Charsb:

3

Nut:

retaining832

1

Ch& motormount

1

Chaasir: maindeck

I

Shield: modulator

2

SCM:

0

Nut:

6-32

1

Panel:

4

Screw: 8-32

10

Insulator

6

Washer: flat

6

Lockwasher:

6

Nut:

0-32

I

Lampholder

1

Chassk: power supply

2

Screw: 8-32 Insulator Washer: Lockwasher: Nut: 8-32

6

Screw: 6-32

2

Lockwasher: No.

6

Washer: flat

2

Clamp: cable Nut: 6-32 w/lock

4

Spacer:

4

Grommet: rubber 3B

Replaceable

x

518"

reardeck

6-32

x

Ilr"

wfiock

front

x

1"

No.

8

No.

8

x

1"flat

flat

No.

8

No.

8

x

112"

6

No.

6

No. 6 x

I14"

Parts

(Cont'd)

DESCRIPTION

head

-

MFR.

-

MFR.

I

MP17

6.6

Figure

6.2.

Location

of

Mechanical

Pam,

Rack

c,

Model

?

Model

4

12A

a

Section VI

U

ITEM

I

thru 7

I

thru

6

2thru7

I

2

3

4

5

6

DESCRIPTION

Complete

Robe

Probe

Assembly

Assembly less Cable Boot

Robe Assembly less law Assembly

Jaw

and Sleeve Assembly

Probe Sleeve Assembly

(includes cable

and

R48)

Ground Body

Locknut

440

Allen setscrew (2 required)

Handle

hp-

PART

NO.

0041242 101

41

2A-21 G

0041242103

5060W

I6

0041 242102

5020.0648

50404407

3030.005

50404405

1

7

0

001

29-5

Cable

Figure

Boot

6-3.

VoltaRe Probe Assembly

412A83A

6-7

Model

412A

Section

VI1

SECTION

RCUIT

C

I

NTR

0

D

U

CTI

0

N

7-1.

7-2. This section contains information necessary maintain the location

1.

COMPONENT VALUES SHOWN

RESISTANCE CAPACITANCE IN MICROFARADS

2.

h

DENOTES CIRCUIT COMMON.

3.

&

DENOTES POWER LINE GROUND.

4.

5.

Model

of

components mounted on the range switch. boards.

--

,

412AIAR. Figure

IN

OHMS

7-3

shows the 412A/AR, and includes pictorial views

AS

FOLLOWS UNLESS OTHERWISE NOTED.

DENOTES ASSEMBLY.

DENOTES MAIN SIGNAL PATH.

VI1

DIAGRAMS

Figures 7-1 and 7-2 give the location within the cabinet model and rack

to

respectively.

NOTES

Figure

74

is a schematic diagram

of

other components

model

instruments,

of

the

of

the circuit

Model

6.

-

7.11

8.

c

9.

10.

11.

METER DEFLECTION.

DENOTES FRONT PANEL MARKING.

L,

1

DENOTES REAR PANEL MARKING.

DENOTES SCREWDRIVER ADJUST.

y

AVERAGE VALUE

DC VOLTAGES MEASURED WITH RESPECT TO CIRCUIT COMMON

SHOWN,

DENOTES FEEDBACK PATH.

OPTIMUM VALUE SELECTED AT FACTORY.

(A),

LINE VOLTAGE AT

115

V, AND

NO

00

1

29-5

7-1

I

Section

VII

DEMODULATOR ASSEMBLY

,--

--

--.

VI01

VI05

(BOTTOM)

VI04

VI03

(TOP)

C116

Figure

I

7-2

7-1.

Location

of

Chassis

Mounted Parts, Cabinet Modcl

00

129-5

Model

4

12

A

DEMODULATOR

MI

t-

R124

Section

VI1

R3S

R28

VI01

VI02

Figure

7-2.

00129-5

Location

of

Chassis Mounted Parts, Rack Model

7-3

Section

VI1

Model

4

12A

I

.[i

L

74

I

0

E

00

1

29-5

37

64

OMA

On

c

3

0-

38

I6

2

0-

39

88.4

I

0-

18

0-

17

0-

16

*

I5

0-

14

0-

9

0-

9

0-

9

0-

9

(t-

0

I40

'1.6

141

8.84

142

!.I6

143

1.684

t44

).216

R45

0.100

l-2

Q

-@

4

0

GREEN/ WHITE

-1

S2A

3

-

BLUlORN

MAo

no

*

5

C

.-

2

r-

I

h

i

r

II

'I1

I

'I

vo

PR

i

~

MODULATOR

ASS

EM

€3

LY

VIEW

FROM

REAR

A

E?

C

DE

F

AM

PL

I

ASS

Fi

EM

BLY

TOP

INSTRUMENT

ER

OF

MA, LEI

SI

RANGE

SWITCH

cc

LE

&,.

'?

Y

.

Model

t

4

12A

a

0

Section

VI1

I

00

1

29-5

7-7

HP 412A, 412AR Operating And Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual