Keithley 440 Service manual

INSTRUCTION MANUAL

MODEL 440

DIGITAL PICOAMMETER

INSTRUCTION MANUAL

MODEL 440

DIGITAL PICOAMMETER

0 COPYRIGHT 1974

: . ,. - :

.I

CONTENTS

Section

Psq:e

SpEClFIC*TIfJNS -___--__-___-____-__---------------------------- i"

1. GENEp&, DESCRIPTION --_-____------_-------------------------

2. OPWTlON --------------------__________I_________---------------

3. Cl&-"lT DESCRIPTpJX --------------------______I_____________---

‘. *C(-ESSORlES -__------------------_----------I--------------------------

5, CUp,UTION __-____----____----____________________I__------------

lj. F\EP,dCEBLE pa?s ----------------------------------------------------

SCHyJJICS -__--___-_---_-----_-----------------------------

10

25

27

32

53

1

3

i.

MODEL 440

ILLUSTRATIONS

Fip. NO.

1
2
3
4

5

6
7
8

9
10
11
12
13
14
15

Franc Panel.
Franc Panel Controls.
Rear Panel CmlfTOlS and Terminals.

Prinrer/Canerol Connector.
Timing Diagram.

Simplified Diagram of Feedback Ammeter.
Gain Calibration of Amplifier.
Damping for Anmeter.
Zero Check Operarion.
Block Diagram of AID Converter.
Delay Hold Circuit.
Incegratar Circuit.
Zero Crossing Decxtar.

"ode1 4401 Buffer Stage.

Chassis Top View, Showing Cal. Adjustments.

Title Page

lb Location of Printed Circuit Boards. 18
17

18
19
20
21
22
23
24
25
26
27
28
29
30
31

Component Layout, K-207.
componenr layout, PC-208.
component Layour, PC-210.
Componene Layout, PC-217.

component Layout, PC-219.

component Layout, PC-222.
Componenr Layour, PC-223.
Componenf Layout, PC-229.
component I.ayouc, PC-209.

component Layout, PC-218.

Test Equipment Set-up far A/D Calibration.
AID Con~erfer Zero Adjusrmenrs.
Elechanical Assembly.

Template, Test Cover, Tap

Ternplace. Tesf cover, Bottom

1
2
2

8

9

10
10
11
11
12

13
13
13
15
17

19
19
21
20
20

23

23

23

24

24

30

31

33

51

52

0874

iii

SPKIFICATIOX

XODEL 440

SPECIFICATIONS

RANGE: 100 picoamperes full scale (0.1 picoampere.

least signdicant digIt) to 10 milliamperes in nine
decade ranges with 100% overrangingonall ranges.

DISPLAY: Four digits tram 000 to 1999; polarity and

overload indicabon.
POLARITY SELECTION: Automatic.
RANGE SELECTION: Manual with automatic decimal

point positmn,ng.
ACCURACY AND RESPONSE TIME:

DAMPING: Varies rise time from minimum value to

approximately 1 second on the lOO.nanoampere to

100.picoampere ranges.

ZERO DRIFT: Less than 0.5% of full Scale per week:

less than O.O54a/“C. after %-hour warmup with

source voltages greater than 2 volts.

DISPLAY RATE: 24 readings per second maximum

(20 per second with 50.M units) adjustable to

approximately two readings per manute.

INPUT VOLTAGE DROP: Less than 1 millivolt for lull.

scale display on all ranges when properly zeroed.

LINE FREQUENCY REJECTION: 60 dB (ratio of peak-

to-peak current of power line frequency or mul*lple
which will cause less than 1 digit of error. to that
error,. 100 dB on 100.p,coampere to 100.“ano.
ampere ranges with mawmum damping. Peak input

current should not exceed 20 milliamperes.

MAXIMUM INPUT OVERLOAD:

Transient: 1000 volts for up to 3 seconds.
Continuous: 600 V using a Keithley or other current

limited (up to 20 mA) Hugh Voltage Supply.

ANALOG OUTPUT: % 1 volt from a 500.ohm sourcefor

full~scale display. Maximum output, 1 millismpere.
Output polanty 3s oppxite input polarity.

PRINTER OUTPUTS AND OUTPUT CONTROLS: Model

4401 accessory provides BCD OUtput and external
cmtrois.

CONNECTORS: Input: Teflon-insulated UHF-type. Ana.

log output: Amphenol 8O.PCZF. Case ground: Bind.
,ng post.

POWER: 105.125 or 210-250 volts (switch selected).

60 Hr. 50.Hz models available. 30 watts.

DIMENSIONS, WEIGHT: 51,‘~” high x 19” wide x 10”

deep: “et weight. 15 pounds.

I

iv

- . _.

t

0874

Safety Precautions

The following safely precautions should be observed before using

this product and any associated instrumentation. Although some iw

strume”f~ and accessoties would normally be used with non-ha/­ardous voltages, there are situarions where hazardous conditions
may be present.

This product is intended for use by qualified personnel who recog-

nize shock hazards and arc familiar with the safely prccaurions re-

quired to avoid possible injury Read the operating information

carefully before using rhe product.
The types of product users are:

Responsible

and maintenance of equipment, for ensuring that the equipment is

operated within its specifications and operating limits. and lor ens

swing that operators are adequately trained.

Operators use the product for its intended funcrion. They must be

trained in electrical safety procedures and proper use of the insrru-

ment. They must be protected from electric shock and contact with

hazardous live circuits.

Maintenancepersonnelperform routine procedures on the product

to keep it operating. for example, setting the line voltage or replac-

ing consumable materials. Maintenance procedures are described in

the manual. The procedures explicitly state if the operator may per-

form them. Otherwise, they should be performed only by service

personnel.

Service
safe installations and repairs of products. Only properly trained ser­vice personnel may perform installation and service procedures.

body is the individual or group responsible for the use

personnel are

trained to work on live circuits, and perform

Users of this producl muzl bc protected from elcclnc hhock a, nil
times. The responsible body musk enwrc Ihal users arc prcvenied
access andhr insulawd from every connection poini. In some cw5s.
~onneckms mw be expored to potential human contact. Producl
users in these circumslances must be trained to protect thanselves
from the risk of elearic shock. If the circuit is capable of operating
at or abwe 1000 volts. no conductive
exposed.

As described in the lnternaiional Electrorcchmcal Commissmn
(EC) Standard IEC 664, dtgiral muldmcler measuring cmam
(e.g.. Keithicy Mod& 175A. 199. 2000, 2001, 2002, and 2010~ arc
Installation Category II. All other inwuments agnai rcrminals are
lnsraliation Category I and mw no1 be connccxd 10 mani

Donotconnect switchingcards directly to unlimited powcrcircults,
They are intended to be used with impedance limited sources,
NEVER connect switching cards directly to AC mains. When cons
netting sources to switching cards, install prorective dcwces to llm­it fault current and vollage to the card.

Before operating an instrument. make sure the line cord is connecr­ed to a properly grounded power recepraclc. Inspea the connecring
cables, test leads. and jumpers for possible war. cracks, or breaks
before each use.

For maximum safety, do not touch lbe product. iest cables. or any
other instruments while power is appiicd to rhe circuit under [es!

ALWAYS remove power from the entire lesl system and discharge
my capacitors before: conneaing or disconnecrmg cables or jump­us. installing or removing switching cards. or making internal
changes. such as installing or removing jumpers.

part

of the circuit may be

Exercise extreme caution when a shock hazard is present. Lethal
voltage may be present on cable connector jacks or test fixtures. The
American National Standards Institute (ANSI) states that a shock
hazard exists when voltage levels greater than 30V RMS. 42.4V
peak,

or 60VDC are

present.

A good safety practice is to expect
that hazardous voltage is present in any unknown circuit before
measuring.

Do nor touch any
common side of the circuit under test or power line (earth) ground.
Always make measurements with dry hands while standing on a
dry, insulated surface capable of withstanding the voltage being

measured.

ObJecr

that could provide a conem path to Ihc

The instrument and accessories must be used in accordance with its
specifications and operating instructions or the safety of the equip­ment may be impaired.

The WARNING heading in a manual explains dangers that might
result in personal injury or death. Always read the associated infor­maflon very carefully before performing the indicated procedure.

Do not exceed the maxjmum signal levels of the instruments and ac­cessories, as defined in the specifications and operating informa­tion, and as shown on the instrument or test fixture panels, or
switching card.

When fuses are used in a product, replace with same type and rating
for continued protection against fire hazard.

Chassis connections must only be used as shield connections for
measuting circuits, NOT as safety earth ground connections.

If you are using a test fixture, keep the lid closed while power is ap­plied to the device under test. Safe operation requires the use of a
lid interlock.

Ifa@ SCI~W is present, connect il to safety earth ground using the
wire recommended in the user documentation.

Then

symbol on an instrumenr indicates that the user should re-

fer to the operating instructions located in the manual.

Then

symbol on an instrument shows that it can source or mea­sure 1000 volts or more, including the combined effect of normal
and common mode voltages. Use standard safety precautions to
avoid personal contact with these voltages.

The CAUTION heading in a manual explains hazards that could
damage the instrument. Such damage may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and
all test cables.

To maintain protection from electric shock and fire, replacement
components m mains circuits. including the power transformer, test
leads, and input jacks, must be purchased from Keirhley Instru­merits. Standard fuses, with applicable national safety approvals,
may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as
long as they are equivalent to the original component. (Note that se­lected pans should he purchased only through Keithley Instruments
to maintain accuracy and functionality of the product.) If you are
unsure about the applicability of a replacement component, call a
Keirhley Instruments office for information.

To clean an instrument, use a damp cloth or mild, wafer based
cleaner Clean the exterior of the instrument only. Do not apply
cleaner directly to the instrument or allow liquids IO enter or spill
on the instrument. Products that consist of a circuit board with no
case or chassis (e.g., data acquisition board ior installation into a
computer) should never require cleaning if handled according to in­structions. If the board becomes contaminated and operation is af­fected, the board should be returned to the factory for proper
cleaning/servicing.

Rev. 2J99

MODEL 440

SECTION 1.

GENERAL DESCRIPTION

Cancrol

RANGE Switch (S1202)

POWER SWifCh (S102)
ZERO CHECK (SL201)
ZERO ADJUST (R1211)
D.424PINC conrro1 (R1221)
DISPLAY RATE (R1201)

0874

Functional Description Paragraph

Sees full range sensitiviq.

Controls power to

instrument.

Selects Zero Check Mode.

Adjusts the zero offset.
Adjusts damping.

Adjusts the

A/D Conversion rate.

2-3 a
2-l b
2-3 c
2-3 e
2-l d

2-l f

1

GENERAL 0ESCR1PT10N

MODEL 440

POWER

Suicch

s102

DISPLAY RATE

Switch S1203

RANGE

Switch

DAMPING

ZERO Gl-0”“d

Switch concro1

51203

It1211

ZERO CHECK

POS e

51211

INPOT

Receptacle

n210

Control or Terminal

I

117-234V Swirch (SlOl)

FUSE (FlOl)
ANALOG OLTPVI (51213)

FRI>lTEI(/CONTKOL (31212)
S?.uE

2

FIGURE 3.

Rear Panel Controls and Terminals.

TABLE 1-2.

Rear Panel.

Functional Description

set* 117 or 234V operation.
Type

3AG

Slow Blow: 117V-3fSA

234V-3/16A

Provides a recorder ourput.
Provides SCD Ourputs from a 50-pin connector.
Cover plate for mounting a" additional SO-

pin Connector.

Paragraph

2-5
2-6
2-6

“ODE‘ 440

OPERATION

SECTION 2.

2-l. INPM CONNECTIONS.

Inp,,t Rece,,w.cle. The Input connecfor (51210)

a.

is a Teflon-insulated UHF t.,w (Keithlev Part No. CS-

64). A mating (CS-49) conniCtor is supblied far mak-

ing

custom cables. The center terminal of

tor is in the Input High terminal while the outer
shield is case ground.

A separate grounding past “6”

is provided for system ground connections.

b. IDPUC Cables.

Input connections should be made
using coaxial cables which are low-noise types with
graphite coaring beeween dielectric and

Far eu~eom length

cables Keithley Part No. SC-9 Low

Noise Coaxial Cable should be used.

1. Model 2611 Coaxial Cable. This cable is a

pre-assembled cable 24 inches long having a IMF male

connector on each end.

2. Part No. 19072C

cable is a pre-assembled cable 30

a UHF male connecmr an one

Coaxial Test Cable. This

inches long having

end

with alligator clips

on the ocher.

C. Insulaeio”.

Use high

resisrance, low-loss mafe-

rials such as sapphire, reflan, polyethylene or poly-

scyrene for insulation of the input circuit.

NOTE

The input terminal should be protected from con-

raminacion $0 chat the insulation will not be

degraded,

Clean, dry connections and cables are

very important to maincain the value of all in-

sulation materials.

Even the best insulation

can be compromised by due, dirt, solder flux,

films of oil or water vapor. A good cleaning

agent is methyl alcohol,

which dissolves most

comon dirt without chemically atracking the

insulation.

the connec-

shield braid.

OPERATION

1. Thermal EMUS. ThemaeLectric potentials

(thermal

between

can often be large compared to the signal to
measured. To minimize the drift caused by therma!
emfs, use pure copper leads “herever possible in
the source circuit.

mainmining constant junction temperatures espec-

ially by using a large hear sink near the connec-

tions.

mal Connection Kit contains ali necessary materials

far making very low rhemal copper crimp connections

far minimizing Chermal effects.

2. AC Electric Fields. The presence of electric

fields generated by paver lines or ocher sources

can have an effect on instrument operacion. AC

voltages which are very large with respect co the

full-scale range sensitivity could drive the ac
amplifier into sacuracion, thus producing an erron­eous dc output. Proper shielding as described in

paragraph 2-1, d can minimize noise picl-up when

the instrument is in the presence of large ac fields
or when very sensitive measurements are being made.

3. Magnetic Fields.

neck fields can be a potential source of ac noise.

Magnetic flux lines which CUL a conductor can pro­duce large ac noise especially at power line fre-

quencies. The voltage induced due co magnetic flux

is prnpor~ional co ehe area enclosed by the circuit
as well as the rate of change of magnetic flux. For
example, the motion of a l-inch diameter loop in the

earth’s magnetic field will induce a signal of sev-

era1 tenths of a microvolt. One way to minimize

magneric pickup is to arrange all wiring so that the

loop area enclosed is as small as possible (such as

rwiscing input leads). A second way to minimize

magnetic pickup is co use shielding as described in

paragraph 2-1, b.

emfs)

are generated

by thermal gradients

two junctions of dissimilar metals. These

be

Drift can also

The Keifhley accessory Model 1483 Lou Ther-

be minimized by

The presence of scrang nag-

2-2. MEAS”RENENT CONSloEiWTIONS

a. Noise. The limit of resolurion in voltage and
current measuremen?.s is determined largely by rhe
noise penerared in rhe source. stray law-level noise

is presene in some form in nearly all electrical cir-

cuirs. The instrumenr does nor distinguish between

stray and signal currents since it measures the net

current. When using the picoampere ranges, consider

the presence of low-level electrical phenomena such
as thermocouples (thermoelectric effete), flexing of
coaxial cables (triboelecrric effect), apparent re-

sidual charges on capacitors (die-leccric absorption),

and baCCery action of two terminals (galvanic action).

0874

b.

ShieldinK.

1.‘ Electric Fields. Shielding is usually neces-

sary’when the

instrumnt is in

the presence

of very

large ac fields or when very sensitive measurements
are being made.
cuit and leads

a~ only one point. This provides a “tree”

The shields of the measurement cir-

should be connected together co ground

config-

uration, which minimizes ground loops.

2. Magnetic Fields. Magnetic shielding is useful

where very large magnetic fields are present. Shield-

ing, which is

or

cables,

cuir,,

the

available in the farm

of plates. foil

can be used to shield the measuring cir-

lead wires, or the instrmenr itself.

3

OPERATION

MODEL 440

Damping. The amount of high frequency ooise

C.

which will be observed on the picoammerer is deter­mined by:

I) the noise pickup ae the input, and 2)
the bandwidth of the amplifier circuir. The front
panel DAMPING Confrol (R1221) controls the amount of
filtering from a minimum (NW) value (as stated in
the rise time specification) fo a maximum value
(approximately 1 second on PICOAMP range) when see
fully clockwise.

d.

Accuracy.

The accuracy is specified in terme
of a percent of reading on eech range. An additional
fl digit is specified since the A/D conversion has an

&herenc +I digir uncertainty. Noise and source re-

sistance conditions should be evaluated as additional

measurement considerations.

e. Source Resistance.

The value of source resisf­ante em affect the measurement if the loading effect
of the picoammecer is significant. To avoid a degrad­ation of zero drift. rhe picoammeter range should be

selected so that the range feedback resistor is much

less than the source resistance. The zero drift
specification is valid only for source voltages greac­er than 2 volts. The suggested minimum source resisc­ante for each range is given in Table 2-l. The amounf
of degradation of the drift specification is given by

the following equation.

Drift =

%/week x Nominal Gain =

Effective Gain

where Nominal Gain = K

Effective Gain = (w)(q

f. Overloads. A unique input circuit provides
complete overload protection with fast recovery. The
maximum transiene overload is 1000 voles for up co
3 seconds.

The maximum continuous overload is 600

volts using a current limited supply (up to 20 mA)

such as Keichley Models 240A, 245, or 246.

2-3. FRONT PANEL CONTROLS.

a.

RANGE Switch (51202). This switch selects the

full scale displsy range in nine decade steps. The
dial is designated in engineering units, that is,
PICO AMPS, NAN0 AMPS, MICRO AMPS, and MILL1 AMPS.

b. POWER Switch (SlOZ). This swirch controls the

line power to the instrument.

C.

OPERATE/ZERO CHECK Swifch (51201). This swirch
selects either normal operation or zero check opera­tion.

d. DAMPING Control (R1221). This control varies
the response time of the picoanrmeter on the PICO AMP
and NAN0 AMP ranges.

e.

ZERO Control (R1211). This control adjusrs the

zero display.

The ZERO Control should be used when

in ZERO CHECK mode.

f. DISPIAY RATS Control (R1201). *his control ad­justs the A/D converter conversion rate from 24 reed­ingslsec. (MAX) to 2 readingslmin (appron).

Example: If RANGE =

RF =
RS =

Then

Rs I' RF = 3 = 1.5

RS

TABLE 2-l.

Suggested Minimum Source Resistances.

RANGE

Selected

100 PICO-AMPS
1

NANO-AMP

10 NANO-AMPS

100 t&NO-AMPS

1 MICRO-AMP
10 MICRO-AMPS
100 MICRO-AMPS
1

MILLI-AMP

10

MILLI-AMPS 105

Resistance (ohms)

1010
109

108
107

1.02 x 106

1.05 x 105

1.05 x 104
1050

RANGE

1 NICROAMP

1.02 x 106
2 x 106

-i-

Source Resistance

2 x 1010
2 x 109
2 x 108

2 x 107
2 x 106
2 x 105
2 x 104
2 x 103
2 x

102

2-4.

OPERATING PROCEDURE.

a. Preliminary Procedure.

1. Check the 117-234V Switch (SlOl) dit the rear

panel for proper line voltage.

2. Check for proper rated fuse.

3. Connecr the power cord, place the POWER switch

ON, and allow a 30 minure warmup for critical meas-

urements.

4. Adjust the ZERO Control (R1211) as necessary.

Zero is indicated by alternately flashing + polarity

lights.

5. Connect the source es described in paragraph

2-l.
b. Measurements. The Model 440 measures current

over a full-scale range from 10 milliamperes (10m2 A)
fo 10C1 picoampere (lo-10
picoarhpere (lo-l3 A).

A)

with resolution to 0.1

The display will indicate either
a positive or negative input current automatically.
(A positive curreot is defined as a positive "conveo­rional current" applied ac Input High with respect co
case ground.)

4

0874

1 x 10-4 A 100 MTCKO-AMPS 100.0
1 x m-3 A 1 +llLLIlAME 1.000

L I x lo-? h 10 MILLI-AMPS 10.00

2-5. ANALOG OUTPUT. The analog output on the rear

x 10-6

x 10-3

x 10-3

2-6. DIGITAL OUTPUT.

a. cenera1.

1. The Model 440 has provision for the installa­tion of OUtpUt buffer printed circuit boards co
&rain Binary Coded Decimal (NO) outputs. Two 44­pin card-edge cOn*eCeOrS are installed and complete­ly wired on Che main PC board.

0874

CO”“eCrOr:
Model 440. “ueput mating connector supplied with

4401.

so-pin Amphenol xicro-Ribbon mounted on

Full Scale Magnitude. The magnitude of the

1.
reading is indicated by BCD outputs which correspond
to the three front panel display lights as shown in
Table 2-5.

TABLE 2-5.

Full Scale Magnitude

TABLE 2-7.

PolariCy Output

:onneccar

Pin No.

1

2
26
27

3

4
28
29

‘-

5

6

30
31

2. overrange Indicarian. Overrange is indicated

by the faurrh (from the right) display light and
corresponding BCO output as shown in ~ahle
Overload is indicated by a blanked display and

corresponding BCD output. The output at pi” 33
will he a logic “1” when the magnitude of ehe digital
display exceeds 1999.

Overrange and Overload Oucpurs.

OUCp”t Digits

1 x 100
2 x 100
4 Y 100
8 x 100

1 x 101
2 x 101
4 x 10’
a x 101

1 x 102
2 I 102
4 x 102
8 x 102

TABLE 2-6.

Dee ima 1

2-6.

~<mtx:c Indication (Exponent). The range or

4.
exponent has a corresponding BCD oufpue as shown in
Table 2-8.

ponent uses 2 coiumns to represent information far

exponents from 00 thr” 10.

CO”“eCCOC

Pin No.

9
10
34
35

The print-auf of the RANGE Swifch ex-

TABLE 2-8.

Range or Exponent Indication.

OUtpUt

1 x 100 Range
2 x 100 Range
4 x 100 Range
8 x 100 Range

Decimal
Digits

i

External cancro1.

d.

1. General. To obtain optimum *ystem p%ffbrm-

ante,

440 synchronously with other digital equipment,
such as printers, paper tape punches, computers and
other daea handling devices. The Model 440 with

4401 Printer Cards installed provides several print­er control connnands for the purpose of synchronizing
external equipment to achieve maximum conversion

rates.

if is often desirable CO operate Che~Nodel

1
2
4
8

Polarify Indication. The polariey is indicated

3.
automatically by ehe Polarity Indicator and corres­ponding BCO output as shown in Table 2-7. Addition­al BCO levels are available at pins 14 and 39 for
use with some printers. The zero check made is in­dicaced by a BCD output from pin 38. Four pins may
be used to obcain BCD polarity codes for external

printers, where 1010 = + and 1011 = - prineer chsr-

acters.

6

2. Applications. Several alrernate approaches

may he used in designing the overall system control

scheme.

a) The Model 440 can be used to provide master
conerol of external devices so that the maximum
possible conversion race* can be obtained.

h) An external device can also he used for
master control such as a high speed printer.

c) A completely independent “master clock” can

be used for system control far maximum flexibiliry.

3. Description of external controls.

‘71OI.C 1”. This control inhibits A to D

=I
conversion at the instant a closure to ground is
made.

ly when the “HO:D 1” line is opened.

The conv’rsion cycle will resume immediate-

1. Standard Outpue Codes and Levels. The stand­ard o rpue code for Hodel 4401 Printer Output Cards
is l-2-4-8 Binary Coded Decimal (BCD). A binary
coded decimal digit is represented by a four-bit
binary code as show,, in Table 2-12. refer to figure

for a circuit diagram oI the Model 4401 Stand=,rd

Prineer outpue buffer stage.

2. PKpmx/CONTROL connector. nie PKINTEK/CONTROL
Connector used o,, the Model 440 provides for connec­tions to 50 pins as shown in Table z-11.

The mating
connecfor supplied with Model 4401 is an hmphcnoi
Part Number 57-,050o or Keithley Part Number cs-220.

available on special order.

3. Analog-fo-Digicai Conversion Cycle.
a) The analog-Co-digital conversion cycle can

be inifiafed in any one of three ways.

1.) DISPUY RATE concro1 set at MAX. With the
DISPLAY RATE Control set at MAX, the end of one
compleLe COnverSion triggers a second conversion
to obrain the maximum co”“ersio” rate of ZL read-

ings per

second.

2.) DISPLAY RATE ConLrol SeC at Other man EWY.

WiCh etle DISPLAY RATE Control set at soale psi-

tion other than MAX,

(uncalibrated control set­ting) the end of one complete conversion rriggers
a second conversion which is delayed by a speci-

fic time interval (DELAY). The time delay is a

funceio” of he position ai a continuously vari­able control to provide a co”“ersio” rate from
24 readings per second to 2 readings per minute.

5. Nigh and Low Keference. The PRINTEKICONTROL

connecror pro”ide* f”0 reference voltages, High
(t8”) and Low (+ZV). These levels may be used to

define the ‘~HICII” and “LOW” digital output states

1ar exeerna1 printing or computer devices.

Typical Digital Outputs.

Front Panel

Digital Display

RANGE Significant Range

Sefting Polarity

-093.6 PICO-AMP
+0.275 NANO-AMP

+ 0

-17.31 NAN”-AMP
c122.3 NANO-AMP

10.096 MICRO-AMP

+ 1
+ 0

-07.81 MICRO-AMP
+165.2 MICRO-AMP

+ 1

-L.921 MILLI-AMP

-06.17 MILLI-AMP

+(bk*k)

MICRO-AMP +

TABLE Z-10.

Digif & Overload

0

1

0

i

0

8 000 OS

3.) ‘HOLD 2” with TRIGGER Control. With the

“HOLD 2” command grounded, a ciosure to ground
of the “TRIGGER” command initiates one complete
conversion cycle. A second conversion viii

foilow only if the TRIGGER cormand is removed
and m-applied a second time. The maximum con­version rate using an external trigger is 24
readings per second.

Nag.

EXP.

936 -0.936 x

275 09 +0.275 x
731 08 -1.731 x
223 07 +1.223 x

096 06 to.096 Y

781 05 -0.781 x
652 04 hL.652 x
92, 03 -1.921 7.
637 02 -0.637 x

InrerprelJrio”

10‘10
ld
10-a
10-7
10-6
10-5

1V4

10-3

lo-*

positive overloac

0874

7

OPERAT‘ION

TABLE 2-11.

PRINTER/CONTROL Connector Pin Identification.

Pin No.

13
14

15
lb

17
18

19

20

output

1 x 100 Polarity

+ 15" _-_
Blank --_

ELIkInk ___

b 15" -__

+ 3.6V ---

Blank --­Blank ---

Function Pin NO.

O"tp"r

38 1 x 10

39 + 15"
LO Blank

41 Blank
42 - 15"

43 Common
44 Grounded

45 Grounded

Funcrion

Zero Check

---

---

---

--­__-

21
22

23
24

25

Blank --­Blank ___

i lb" Pulse Print Command

+ av Hi Reference
/' 2v LO" Reference

L

FICURF. 4. Printer/Control Connector.

46 Grounded Trigger
47 Blank

48 Blank

49 Blank
50

Blank

___

---

---

--_

0:;;;

HOOEL 440

OPERATION

b) Conversion Cycle Timing. The Conversion
Cycle is composed Of three timing periods, namely.
Integrator zero, Integrator Sampling, and A-D

Counting period.

Refer to Timing Diagram Figure

1.) Integrator Zero Period (ZERO). “hen a
trigger pulse initiates a new conversion cycle,
the Inregracar circuit is zeroed for a period

not to exceed 8.33 milliseconds for 60 Hz aper­ation.

The Integrator Zero Period is 10.00

milliseconds for 50 Hz operarim.

2.) Integrator Sampling Period (INTEGRATE).

The Ineegraeor Sampling Period

follows automat--

ically the Integrator Zero Period and lasts for

a duration of 16.67 milliseconds for 60 Hz op­eration. The Integrator Sampling Period lasrs

for a duration of 20.00 milliseconds for 50 Hz

operation.

3.) A-D Counting Period (COUNT). The A-D

Gunring Period is initiated immediately follow-

ing the Integrator Sampling Period.

The actual

counring rime durarion vi11 depend on the actual

incegraror

pulses or 16.67 milliseconds. Following the

voltage up to a maximum of 2000

clock

counting period a Buffer/Storage cormand is
automatically generated in order to store the

new reading in the output registers.

4.) PRINT COMMAND. The PRINT COEPWNO signal

is used to trigger external printers or paper

tape punches. The PRINT CObDL\ND

signal

is de-

layed 10 microseconds to allow the Storage Reg-

isters to settle. The PRlNT COMMAND pulse

width

is approximately 100 microseconds with a I volt/
microsecond rise time into a 1 kilohm load. The
pulse smplitude is approximated by ehe follow-

ing equation:

= 14R/(R + 2200~

%

where R is the output load resistor.

The “OFF” state is less

ihan co.4 volt with

approximately 1 milliampere sink current.

NOTE

The data

stared in the Output Registers will not
change for at leasr 25 milliseconds for 60 Hz op­eration. If the front panel controls are
the Zero Check BCD o”tput vi11 be

changed only.

charmed.

0874

FIGURE 5.

Timing

Diagram.

9

CIRCUIT DESCRIPTION

MODEL 440

SECTION 3.

CIRCUIT DESCRIPTION

3-l. GENERAL. The Model 440 Digifal Picoamerer con­sisfs of two separate sections packaged together in
one chassis for optimum performance and convenience:
a sensitive picoammerer and an analog-to-digital con­verrer.

Picoameeer. The picoameter is a linear dc

a.
amplifier connected as a feedback ammeter with nine
CUrrent ranges.

b.

A/D

Converter. The analog-to-digital converter

is a dual slope, integrating type converrer with med-

ium conversion race. cold cathode readout tubes, BCD

output options and external control.

3-2. PICOAMMETER

a. Ooerarion. The picoamerer consists of a sms­itive, linear dc amplifier with a 1 volt full scale
sensitiviey. The amplifier provides an analog output
up to 2 volts for*a 100% overrange display. The
RANGE resistors are connected across the feedback of

the amplifier.

A

simplified diagram of a feedback

anmeter is shown in Figure 6.

b. Circuitry. The amplifier input stage is a pair

of insulated-gate, field-effect transistors (IGFET)
designated Q1201 and Q1202 connected in a differential
configurarion. The circuit designared 218508 is a

special overload protection circuit on the Input FET
board (which connects to 51201). The gate of Q1201 is
connected;to the input through 10M ohms. The gate of
Q1202 is referenced to ground. Poteneiometer RI205 is
an internal COARSE ZERO adjusment.

Potentiometer
R1206 is an internal Balance control. Transistors
Q1203-Q1204 form a second differential amplifier stage.
Potentiometer R1211 is a fronr panel ZERO adjustment.
Transistor Q1205 and emitter follower transistor Q1206

provide sufficient gain for the analog output and

A/D

converter. The analog output is connected through
R614 (499n) fo the dc amplifier output (the junction
of R1220 and D1203).

The full scale current sensitiv-

ity is determined by ehe range resistor connected

across the feedback.

The range resistance RF is com­posed of a fixed resistance Rl plus a calibrarion ad­justment resistance R2 as shown in Figure 7.

Potent-

iomerer Rl221 controls the amount of damping on rhe
PICO AMP and NAN0 AMP ranges only.

Switch S1203 de­feats the damping feature when set to 'WIN" or open
position.

The damping circuir is shown in Figure 8.

When switch S1201 is ser fo ZERO CHECK the picoamerer

is connected as shown in Figure 9.

Ie should be noted
that the feedback resistor RF is shorted out & the
inpur High terminal is shorted to ground.

C-

NPUT

FIGURE 6.

10

Simplified Diagram of Feedback &meter.

GAIN
ADJ.

FIGURE 7. Gain Calibration of Amplifier.

OUTPUT

CIRCUIT DESCRIPTIOX

,,‘-.

m GROUND

3-4. ANALOG-TO-DIGITAL CONVERTER

a. General.

A

detailed block diagram of the A/D

DAMPING \;
CONTROL <

OPERATION.

co"ver~er is shown in Ffgure 10. The analog-to-digital
converter operates using a dual slope integration tech­nique which has inherent line frequency noise rejection.
The analog signal is applied to the integrator for one
complete line frequency cycle.

The analog signal is

then removed from the integrator input. The voltage

on the integrator is then driven to zero fo complete

the voltage-co-rime conversion. The time interval to
reach a "Zero Crossing" is counted and displayed on
the "Readout" in proportion to the original analog
signal. The sequence is then repeated for a second
reading. A Timing Diagram is show in Figure 5.

b. Circoifs. The

AID Converter

is

composed

of nine
major circuits which perform the analog-to-digital con­versions and provide various control commands.

1. Oscillator or Clock

2. BCD counter

3. Delay Hold

4. Program/Decoder

5. 1nregraror

6. Zero

7.

Crossing

!&rector

Buffer/Storage Register

8. Decoder/Driver

9. Numerical Readout

C. Oscillator or Clock. The Oscillaror produces

oulses at a rate of 120 kilohertz for Electrometer

using 60 Hz line power.

The 50 Hz "nice have a pulse

rate of 100 kilohertz.

d. BCD Counter. The BCD Counter counfs ?he

Clock

pulses with a roral range of 5000 counts. The Counter
is composed of 4 individual coyntere designated 1, 10,
100, and 1000.

cu.-,-

I

1

/-k!

GROUNC

1. The "l", "lO", and "100" coun?ers have a ca-

pacity of ten counts each.

2.

The "1000" counter has a capacity of five

cooncs.

3. The tocal capacity of all four co""ters is

5000 CO""tS.

e. Delay Hold. The Delay Hold circuit conrrols the
DISPLAY RATE function and external Hold and Trrgger
connrands as shown in Figure 11.

length

of time between A/D conversio"s when the front

It determines the

panel DISPLAY RATE Control is set to any position
other than MAX. The clock is stopped at the beginning
of the ZERO (2) period for a time determined by the
rocafion of the DISPLAY RATE Control. re ensures thaL

when the Hold 2 is grounded the conversion in process
will be completed and new data will be stored in the

output storage register.

Then the clock will be in-

hibited at the beginning of the ZERO period (2). The

instrument will remain in this condition indefinitely

until Hold 2 is released or until Trigger is shorted

to ground.

Afrer conversion, the insrrumenr will again
be inhibited at the beginning of rhe period (2). If
bath Swifches Sl and S2 are closed, the conversion
cycle works in the following manner. After the pre­vious conversion has been completed, the leading edge
of the program comrt~nd (2) resets the flip-flop. In
this new condition Q is high end, therefore, rhe clock
gives no ootpuf. Af that time, rhe unijunction timer
begins ifs cycle and. after the appropriate rime, pro-

duces a pulse chat sets rhe flip-flop. This changes
Q to a low scare and a new conversion cycle begins.
After the reading has bee" completed, the (2) co-and

again resets the flip-flop end the timer again issues
a new pulse Co set the flip-flap.

0874

11

A-TO-0

CONVERTER

I

!

I

I I

I I I I I

’

MODEL 440

f. Pro~ram,Decoder. The Program/Decoder circuit
produces event coman*s to control the overall Se­quence of events for a complete

g. Integrator. The Integrator circuit operation is

AID

conversion

composed of three periods.

1. Zero Period. During this period the integra­tor amplifier is zeroed by the closure of switch Sb.
Switches S,, S,. and Sd are open to prevent ince­gramr charging as shown in Figure 12.

CIRC”IT DESCRIPTION

2. Integration Period.

switch Sb, s, ,

and Sd are open. Switch S, is closed

During this period,

to permit charging by the analog voltage for a per­iod of one line cycle.

3. Discharge Period.

During this period, switch

S, is open co prevent further charging by the analog

signal. Either swirch S, or Sd is closed to drive
the Integrator voltage fo zero. A reference current

of opposite polarity to the inpue current is applied

through either switch S, or Sd. The Discharge per­iod ends when the Zero Crossing Dereccor circuit de­tects a zero Integrator output.

h. Zero Crossing Detector. The Zero Crossing Detec-

tor circuit provides a “High” or “Low” level output

depending on the polarity of the detected input. Refer

to Table 3-1 for a description of voltage outputs.

TABLE 3-l.

zero crossing Detector OUtput Levels.

BufferlSrorace Resister.

i.

The

Buffer/Storage

Register is coaposed of “flip-flops” arranged to copy

rhe states of the various BCD counter.=. The Buffer/

Storage Register requires a Buffer Score command be-

fore any infocmafion can be transferred. The “flip­flop” circuits provide coded informrim for Decoder!

Driver and the BCD outputs.

FIGURE 11. Delay Hold Circuit

J Decoder/Driver. ‘.

The Decoder/Driver circuit de­cades the BCD information from Che Storage Regisrer
into fen-line decimal code. The Driver circuit ehen

drives rhe proper numeral in each of the Numerical
Readout tubes.

k. Numerical Readout. The Numerical Readout can­sists of four numerical indicators and one polarity
indicator driven by

the

Decoder/Driver, Polaricy and

Overload Drivers.

I.. Summary of Operation.

The operarim of the

A/D Converter can be described by considering a

typical conversion cycle.

0874

CIRCUIT

DESCRIPTION

2. The Delay Hold circuit gates the output of

the Oscillator depending on the state of the “RS

flip-flop” and the “Hold 1” control line. A uni­junction timing circuit provides a delay period
before a conversion is initiated. The time delay

is selected by the front panel DISPLAY RATE Control

3. The BCD Counter .serves as a master timing

control for the A/D Conversion cycle. The timing

is accomplished

five coded states, namely 0, 1. 2, 3, and 4.

4. The Program/Decoder controls the sequence of
connnands based on the coded srates from the BCD
Counter. The decoded commands are described as

shown in gable 3-2. The “2” cormnand iniciaces the
integrator ZERO period which removee any residual

charge on the integrator capacitor. The “3.4”

command iniciares the INTEGRATE period which per-

mits an integration of the analog signal.

end of the INTEGRATE period, the “0.1” command in-

itiates ehe COUNT period.

Cameand

by

‘ttOOO’~ counter which has

the

TABLE 3-2.

Function

At

the

MODEL 440

ANALOG-TO-DIGITAL CONVERTER CIRCUITRY.

3-5.

a. General. The circuits described in this Section
are located on the various Sub-Assemblies listed be­low and in Table 7-2 of Section 7.

1. Oscillator Board, PC-217.

2. ‘Integrator Board, K-219.

3. Display/Overload Board, PC-241.

4. Readout Board, PC-229.

5. Polarity Board, K-207.

6. Output Buffer Board, PC-218.

7. Output Buffer Board, PC-209.

b. Oscillator Board.
portions of three circuits:
circuit, the Delay/Hold circuit, and the Discharge­Voltage Current Source circuit.

I. Oscillator Circuit.

Y501, and phase ehifc capacitors C501, and C502 form

a “Colpitts” type oscillator. Capacitors C503 and
C504 are used for trimming the oscillator frequency.
The output is taken from the collector of transistor
Q510 which is a common emitter gein stage used for

squaring the output. Transistor Q507 eerves e5 en

emitter-folldwer to reduce o”tp”t impedance.

The Oscillator Board contains

the Ocsilla?.or (clock)

Transistor Q501, crystal

t -

5. When the “3,4” command is given, the integra-

tor is charged by rhe analog signal for a period

of 1 line cycle of 16.67 milliseconds.

6. When the “0,l” command is given, the analog

signal is removed and the integraeor o”tp”t is
driven to zero by a reference current.
Crossing Detector senses a zero crossing of the

Integrator output and removes the reference current.
The

The +1.5 volt levels are provided for control of

the Incegracor and Polarity Storage Register.

pulse command is also produced to initiate a Buffer/

Store and Win? Command o”Cp”C.

7. When the Buffer/Store command is given, the
Suffer/Storage Register copies the ECD Counter­states at chat insfilnf of time. The BCD coded in­formarion in the Register is then available for the

Decoder/Driver and external printout.

8. The Decoder/Driver decodes the Buffer/Storage
o”cp”c and drives the Numerical Readout for a dig­ital display.

9. The BCD Output information is available at
the Model 4401 Buffer Card outputs in the form of
positive (+lO volt) tr”e logic (l-2-4-g BCD Code)

10. The conversion cycle is complete when the
BCD Counter reaches 2000 counts and the Program/
Decoder provides a “2” command to initiate a new
conversion cycle.

11. The Unijunction Timing Circuit will initiate

the ZERO period after a present time delay con­trolled by the front panel DISPIAY RATE Control.

2 ZERO

3,4

0.1

Detecror provides

outputs as shown in Table 3-l.

INTEGRATE

COUNT

The zero

2. Delay/Hold Circuit. There are three major

components in the Delay/Hold circuit: an “RS” type

I

A

flip-flop circuit, a “Unijunction” timing circuit

and a “Hold” gate circuit.

a). .“RS” Type Flip-Flop Circuit. The flip-flop

gates the ourput of the clock depending on the in-

puts. at pins R and S.
strucced of gates
identified as shown in Figure 16.

“hijunction” Timing Circuit. The unijunc-

b).
tion timing circuit derermines the time delay be­tween conversion cycles to obtain the desired con-

version rate as determined by the fronr panel DIS-

PLAY RATE Control. The circuit is composed of
transistors 9513 and Q514, timing capacitor C507,
and timing resistors R532 and R1269 (DISPLAY RATE
Control poCentiometer located on the front panel).

“HOLD” Gate Circuit.

C).
for identification of switches Sl and S2. The
“HOLD” gate circuit is composed of gates QASOlA,

QASOlD, and QA502 (A, B, C, and D). Switch Sl is

gate QA5OlA and is controlled by either the “‘HOLD
2” external line or the WAX” position on the

DISPLAY RATE Control.
Q513 which is conrrolled by either the “Q” outpue

of the flip-flop or the “HOLD 2” external line.

The

“HOLD 1” circuit is composed of gates QA502B

and QA502C.

3.

Discharge-Voltage Current Source Circuit. The
Positive current source composed of transistors 9502
end Q506 delivers a cons~anf current of +7.5 milli­amperes Co drive a g-volt zener diode 0602 (located
on the Integrator Board. K-246) when +RRF Terminal

(Pin 13) is greater than +0.7 volt. The negative
current source composed of transisrors 4508 and Q509
delivers a constant current of -7.5 milliamperes to
drive a g-volt zener diode 0601 also located on rhe
Integrator Board, K-219.

The RS flip-flop is con-

QASOlB

and

QASOlC.

Refer to Figure 13

Switch S2

is the transistor

The pins are

14

0874

MODEL 440

Integrator Board. The 1neegratur Board consisrs

c.
of two major circuits:
Zero Crossing Detector circuit.

ctle 1ntegracor circuir and the

I. Integrator circuit. The operation of the In-

tegrator is controlled by the positions of switches

sa. Sb. SC. and Sd.

SWiWh s, is Cransisfor QbO5.

Switch Sb is fra"sisCor 4606. Transistors QbOl

through 9604 are control
off the proper FET switches depending on the signals
ac

pins

of
QAbOl. The feedback capaciror
and Sd (located on the Oscil~acar Board, K-217)
control the current for V-volt zener diodes D601 and
D602.
calibration

11 and 12. The ineegrator

transistors

Resisrors

Q607 and Q608 and integrated circuit

R602 through Rbll are full-scale

resistors.

circuies

arranged to turn

amplifier

is

CbO3. Svitche* S,

consists

2. zero Crossing rleteccor CiTC”if.
Figure 18). The
cascaded amplifiers QA602 and QA603. The zero ad­justment network consists oC
R648, R649, and R650. and diodes D611 and D612.

Transistor

supply for QA603
splicrer circuit consists of
resistors R651, R.652, and R653 and &aces Q.4604 (A,
8, C).

high

gain amplifier is composed of

resistors

9609 and other components form a 6-volt

and the zero circuit. The level-

diodes

(Refer to

R645.

0613 and 0614.

R646,

d. Display/Overload Board. The DisplaylOuerload
Board contains a BCD Counter ("1000" counter). a Pro­gram Decoder CirCUit, and a" Overload Control circuit.

1. The BCD Counter is composed of "J-K" flip-flop

circuits QA301 and QA302.

2. The hoeram Decoder circuit is cornnosed of

gares QA303C and QA303D (3,4 Comand~ ."b QUO&!,

QA304B;QA304C, QA304D, QA305A, QA3058. QA305C.

QA,OSD, QA303E, QA306A. QA306B. and QA306C CO,1 & 2

Commands).

Readoue Board. The Readout Board contains De-

e.
cade Counter circuits, Buffer Storage circuits, and
Decoder Driver and Display circuits.

g. outour Buffer Board. W-218.

This board conrain!

15 buffer circuits to provide BCD Dara and Overload a"~

1. Decade Counter Circuits. Each decade counter
is composed of four J-K flip-flop*. Circuirs QA4Oi
through QA406 are Dual J-K Flip-Flop integrated cir-

CUlfS.

2. Buffer storage circuits. me Buffer storage
register is composed of Dual J-K Flip-Flop incegra­ted circuits QA409 through QA414.

3. Decoder Oriver Circuits. QA415.

QA416, and

QA417 are Decimal Decoder Driver integrneed circuits.

4. Display Circuits. “401, “402, and “403 are

Readout Tubes far Units. Tens. and Hundreds respec­tively.

0874

FIGURE 14. Model 4401 Buffer stage.

CRCUIT DESCRIPTION

MODEL 440

h. Output Suffer Board. K-209. This board contains
six buffer circuits and various gate circuit* fo pra­vide Print Command and Range Signal Prinr signals.

1. Buffer Circuits.

Suffer circuits "'A" through

"E" provide SCD Range informatian.

2. Print Command Circuits.

Suffer circuits com-

posed of cransiscors Q1101, Q1102. Q1104. QllOS,

QllO6, and Q1107 provide

determined by gates

QAllOl

Print

Command signals as

(A, B, C. and D) and

QA1102 (A, 8, C, and D).

Range Signal Circuit. Transistors Q1108, Q

3.

1109, and QlllO comprise a Range Signal Buffer stage

concrolIed by the Range Signal.

4.

Reference Volrages. ~A High and Low Reference

voleage is provided by resistor divider R1114, R1115,

and R1116.

The voltages are -8 volts (High) and b2

volts (LOW).

4-b. POWER SUPPLIES (Schematic 2346SE3.

+ 15 Volt Supplv. The 115 volt supplies tap ac

a. I

power from a secondary of rransformer T101. Diodes

D103, DL05, 0107 and 0108 and capacirors Cl04

and Cl05

compose a full-wave rectifier with filtering. Trans-

istors Qll4 and Q115 form a differential amplifier
which compares the volrage at RI15 with the voltage of
zener diode D110. The difference voltage is amplified

by

rransistor

pair, Q106 and Q107, which series regulare the output

Q109 and

fed to Darlingeon transistor

voltage. TransisCors QL16 and Q117 form a differenrial
amplifier which compares the voltage at RI23 with re­spece ea lo.

The difference voltage is amplified by

.transiscor QL13 and fed to Darlington transisCar pair,

QllO and Q111,-which series regulare'rhe '~13 vole'oue­put. Transistors QlO8 and Q112 limit the output cur-'
ren? to about 200 milliamperes.

b. +3.6 “olr Swpl~. The +3.6 vole supply taps ac

wwer from a

secondarv

of transformer T101. Diodes

blO1 and D,OZ and capHcitor Cl01 form a full-wave ret-

tifier with filtering. Transistor QlO5 amplifies ehe

difference becwee" the +3.6 volt output and a refer-

ence voltage derived from

termined by

resisrors

voltage is amplified

the +I5 vole supply and de-

It103 and R104.

by transistor Q104

The difference

which drives a

Darlingcon transistor pair, QlOl and Q102. The Dar-

lington

Transistor

pair

series

Q103

regulares the +3.6 volt au?put.

limits the output current to abauc 3

amperes.

e. ~170 Volt Supplx. The cl70 ""lf supply taps ac

,mwer from a

&td capacikx Cl12 f&m a

secondarv

of transformer T101.

half-wave

rectifier with

Diode Dill

filtering. Transistor 9119 amplifies the voltage de-

veloped by the resistor divider R128 and R129.

The

output of Q119 controls the series regularor cransis-

Co= 9118 to maintain the +I70 vole output. When the

electrometer is overloaded, and overload signal drives

transistor QUO which in turn controls the volrage at

the base of transistor Q119. The circuie composed of
diode D112, rransi,sror Q120, and resistors R130, R131,
and R132 reduces the +I70 volt .xt,,ut co ~80 volts when
overloading occurs. Grounding the overload input turns
off fransisfor Q120 causing diode D112 fo conduct the
drive 4119.

The reduced ~80 volt output causes blank-

ing on all Numerical Readour Tubes cannected to the

Cl70 “OlC supply.

d. 1210 Vale Oufput. The +210

volt supply is an
unregulaeed voltage supply using the half-wave filrer­ed voltage at diode Dill and capacitor C112.

0874

“ODEI. 440

0874

FIGURE 15.

Chassis Top View, Showing Cal. Adjustments.

,,SXRVICING

MODEL ,440

FIGURE 16.

Location of Printed Circuit Boards.

MODEL 440 DIGITAL PICOAMMETER

sr2\'1c rsc

FIGURE ~17.

component Layout, PC-207.

0874

FIGURE 18.

component Layout, PC-208.

19

SERVICING

MODEL 440 DIGITAL PICOA?+lETER

FIGURE 20.

Component Layout, PC-217.

20

FIGURE 21.

component Layout, PC-219.

0874

0

.

0

.

0

MODEL 440 DIGITAL PICOANNETER

SERVICISG

FIGURE 22.

component Layout, PC-222.

FIGURE 23.

component Layout, PC-223.

0874

FIGURE 24.

component Layout, PC-229.

23

SERVICING

MODEL 440 DIGITAL PICOAMMETER

FIGURE 25.

component Layout, PC-209.

24

FIGURE 26. Component Layout, PC-218.

0874

SECTION 4.

"escriprio": The Model 4401 consists ol two printer
output cards which may be installed at the factory or

in the field since no wiring is required. The ouc,mt

cards plug

into

prcwirrd connectors on the chassis.
KY” OUtpUtS are provided through the use of a so-pin
prcwirrd ““cp”L cO”“eCEor.

ACCESSORIES

0874

ACCESSORIES XODEL 440

wade1 3001 Bench Mounting liif

Description:
the E(odel 3001 is a bench mounting kit for use with

instruments 5-l/k” high x 17-l/2” wide x LO” deep. All
parts are included for conversion of a rack mounted
instrument to bench mounting complete with top COYBC,

handle assembly, non-skid feet end tilt bail assembly.
parts List:

I tern

NO.

1 Cover Assembly

2

gcrev, SLotted 10-32x114 4

Bail Support, Right

3

Bail Support, Left

4

Foot, plastic

5
6 Scrw, Phillips,

Rubber Foot Insert

7
6 Screw, Phillips, 6-32x1/4
9 Tilt Bail

a-32x3fa

Qty. Per Keithley

Assemblv

1
L 192068

1

4 FE-5

4

4 FE-b
2

1 14704B

Part No.
176048

192058

1.

Remove the rack angles attached to the rack m.,unted

instrument.
with the instrument should be used to install the
bench-,style top cover (item 1).

2.

Remove the bottom cover to facilitate the mounting
of the non-skid feet and tilt bail assembly.

a screw driver to t-en the psul-type fasteners on
the cover (about one-half turn clockwise).

3.

InstaLl the bail supports (items 3 and 4) using
b-32 screws (item 8).

4.

Install the plastic feet (item 5) using 8-32 screw
(item 6) in four places.

5.

Install tilt bail (item 9) as shown.

6.

Install bottm wver using pawl-type fasteners.

The four lo-32 slotted screws supplied

“Se

26

DETAIL-A

/-BOTTOM COVER

0874

MODEL 440

SECTION 5. CALIBRATION

NOTE 2.

me top and botCom cover‘s SbO"ld be in­stalled for AID Cunverter and Picosmmeter
calibration. It is recommended that special
punched cap an* bottom CoverB be Fabricated.
see Fipures 30 and 31 for remplates for
covers.

Alcernnrrly, the tap cO"er may be
removed for short periods of time. Afrer
adjuscmenr, replace cover and allow insLru­ment to stabilize for a few minutes before
tile cnl. proCed"re is continued..

Recommended Test Eouiment far Calibration.

E

cALIBRATION

WODEL 440

TABLE 5-2.

I

Power Supply Voltage Verification.

"0ltap;e

+15.00LW

-15.000"

+3.6v

I

b. zero Adjust.

these adjusrmenrs.)

1. Set front panel Zero Adjust (R1211) to mecb-

anical center of adjustme"? spa".

2.

Set Display Rate co MAX.

3. set Range to lOmA.

4. Select ZERO CHECK. "irh "0 input signal con-

nected.

5. set Damping f0 Min.

6.

Connect Null Detector (F) fo Model 440

ANALOG

tor R1210 (lS.ZkR).

volrs at ANALOC OUTPUT (51213).

OUTPUT

7. Connecr II"" (must be floating) across resis-

8. Adjust Coarse Zero (Rl205) for 0 + 2 milli-

I I

Te*t Point

I I

I

(51213).

+15v

-15V
+3.6"

(Top cover must be removed far

1

Tolerance

?SOlllV
to.4v
CO.1"

e. Picoammecer Range Calibration,

1

Care must be exercised so as to avoid over­loads on any range during calibrario". The

Damping control may be used to reduce the

I

ourput: noise on ranges loop* t" 1oo"A if
necessary,

1.

Set Display Pate to MAX.

2.

Select lOOpA range.

3.

Select ZERO CHECK.

4.

Connect DVM to ANALOG OUTPUT of Model 440.

5. Verify output of 0 2 O.lmV (adjust franc

panel zero (R1211) as needed.

Connect Current Source fo Model 440 INPUT

c&o,.

7. Apply +lOOpA.

8. Adjust lOOpA Cal. (R1233) to obtain -1.OOOOV

t O.lmV af ANALOG OUTPUT (51213).

9.

Complete remainder of curre"r range calibra-

tion in accord with Table 5-3.

f. A/D Zero Adjustment.

IMPORTANT

9. Adjust Balance (R1206) for 5.2V + 0.1".

10. Repeat steps 8 through 9 until both readings

are obtained simulraneously.

11. With Null Detector (F) connected, adjust

front panel Zero Adjusr (R1211) far 0 t O.lmV at

ANALOG OUTPUT (51213).

C.

Clock Adjusr. (Top cover must be removed for

this adjustment.)

1.

Ser Display Race to MAX.

2. Connect Caunrer (D) between "CLOCK" test

point on prinred circuit board PC-217 and "GND"

rest point on PC-219.

3. Adjusr Frequency Adjust (C503) on PC-217 far
a Counrer reading of 12OkHz t 1 Hz.
is 50 Hz version, ser frequency for 1OOkHz 2 1 Hz.)

Capacitor C504 (22pF) may be added or removed
fo extend the adjustment range of trimmer
c503.

d. Stabilization.

With power on, allow the Model 440 co stabilize i"

the calibration area for wo hours.

Top/Bottom covers are installed.

(If Model 440

1.

Set Display Rate ar "AX.

2.

Connect Oscilloscope as shown in Figure 27.

3.

Model

wave-form amplitude as shown in Figure 28.

wave-form amplitude as show" in Figure 28.
crease Oscilloscope verrical sensifiviry as "eces­wry (to lmV/div, dc coupled).

Connect DVM to ANALOG OUTPUT (51213) of

440.

4.

Set range to lOOti and HOLD.

5.

Place Model 440 in ZERO CHECK.

6.

Adjust

for a

C O.lmV at ANALOG OUTPUT (J1213).

7.

Set Oscilloscope to following:

a). With INTEGRATOR test poinr connecred to
vertical input, set vertical gain to 5mV/div.,
dc coupled.

b).
horizoncal inpur, set horizoncal gain fo Sms/div.,
ac coupled.

c) .

8. Adjust INTEGRATOR ZERO (R632) to minimize

9. Adjust ZERO CROSSING ADJ. (R649) fo minimize

front panel Zero Adjust (R1211)

Wirh EXT. TRIGGER test point connected fo

Set trigger co EXT. +.

I"-

28

0574

ElOOEI. 440

I”O,,A

2cro Check

+100nr\

-1”OnA
+I”“*

-lo”.\

M.1" ? 0.6%

"Crify

I

0874

OSCILLOSCOPE

MODEL 440
TOP VIEW

across resistors R630

and R631.

10. Set vertical oscilloscope input to GND
(using ACIDCIGND switch) to set reference “0” pasi­cion. Switch to DC and verify that RESET position
coincides with “0”.

+F

FLOATING

VERTICAL
PLUG-IN

5.

Adjust + REF. Conrral

Model 440 display flashing beween +1.999 and blank.

Add or remove jumper wires which shunt re-

siscors

R608,

R609 or

cuit board K-219) to extend cbe range of

adjustment an pofentiometer R611. Resisror

R607

may be changed if necessary.

HORIZ.

PLUG-IN

(R611,

R610

(on printed cir-

K-219) for a

11. With RESET adjusted on oscilloscope grid
line, adjust INTEGRATOR ZERO to set “Integraeor”

waveform wiehin IO.lmV of RESET position.

12. Adjust ZERO CROSSING ADJ. (R649) to obtain
a zero rending on file Model 440 display such that
the polarity indicator flashes + and -.

13.

Remove Oscilloscope and other leads from

Model 440.

1.

Cocnece Currenr Source (A) to Model 440 INPUT.

2. open ZERO CHECK.

3.

Apply a positive inpur current to Model 440.

4.

Adjust Current Source and fronr panel zero
as necessary for ANALOG OUTPUT reading of -1.9995”
t O.lrn”.

6.

Apply a minus input currenf CO Node1 440.

7.

Adjust Current Source and front panel zero
as necessary for ANALOG OUTPUT reading of -1.999%
i O.lnlV.

8. Adjust - REP. Control (R606. K-219) for a

Node1 440 display flashing bemeen -1.999 and blank.

NOTE

Add or remove jumper wires which shunt resis-

tors

R603. R604,

or

R605

(on printed circuit
board K-219) to extend the range of adjusr­ment on potentiometer

R606.

Resismr

R602

may .be changed if necessary.

9. &ce Model 440 in ZERO CHECK.

10. Adjust front panel Zero Conrrol for ANALOG

OUTPUT Of 0 t 0.h”.

11.

Model 440 display should indicare f000.

30

0874

MODLL 440

CA1.I :::;1\1 !:'I;

RESEdINTEGKATE DiSCHARGE

I

"0" REFERE:ICE

,I

OSCILLOSCOPE

SETTINGS

VERT - lrnV/DIV
HORIZ - 5hSii)IV
SYNC - + EXT TRIG

_I

,

FIGURE 28. .A/D Converrer Zero Adjustments.

31

REPLACEABLE PARTS

EIODEL 4Zg

SECTION 6.

6-l. P.EPLACE.ABLE PARTS LIST:

a list of compunents used in this inst.rumenr for user

reference.

The Replaceable Parts List describes rhe
individual parts giving Circuit Designation, Descrip­tion, Suggested Manufacturer (Code Number), Manufac-

A ampere

Cb"a= Carbon Variable
cerrJ Ceramic Disc
Cer Trimer

ComP

DCb

Desig.

EAL
ETB
ETT

Ceramic Trimmer
Com!jo~si~ian

Deposited Carbon
Designation

Elecrrolytic, Aluminum
Electrolytic, tubular
Elecrralytic, tanfalum

This section conrains

Abbreviations and Symbols

F farad
Pig

GCb
k

Ir

M
Mfr. Manufacturer
MtF

MY
NO.

REPLACEABLE PARTS

curer’s

Also included is a Figure Reference Number where

applicable. The complete name and address of each

Nanufacturer is listed in the CODE-TO-NAME Listing

following rhe parts list.

TABLE 6-l.

Figure
Glass enclosed Carbon
kilo (10')

micro (10-6)

Meg (106)
Metal Film

Mylar

Number

Part Number, and the Keirhley Part Number.

n ohm

pica

(10-12)

FC

Poly

Ref.

Printed Circuit

POlyStYrWlt-

Reference
TC" Tinner Copperweld
" volt
w watt

m+ Wirewound
wwar

Vireoound Variable

ELECTRICAL SCHEMATICS AND DIAGRAMS. Schematics

6-2.

and diagrams are

included

to describe

the electrical

Sales Service Department, Keithley Instruments, Inc.
or your nearest Keifhley representative.

circuits as discussed in Section 3. Table 6-2 idenfi-

fies all schematic part numbers included.

b. When

ordering parts, include the

formarion.

HOW To USE THE REPLACEABLE PARTS LIST. This 1. lnefrumene Model Number.

6-3

Parts

List is arranged such that the individual types

2. Uxtrument Serial Number.

of components are listed in alphabetical order. Main 3. Parr Description.

Chassis parts ace lisfed followed

boards and

other subassemblies.

by printed

circuit

4. Schematic

5. Keithley Part Number.

Circuit Designation.

c. All parts listed are maintained in Keirhley

How TO ORDER PARTS. Spare

6-4.

Parts

Stock. A?y part not listed can be made

available upon request. Pares identified by the

a. Replaceable parfs may be ordered through the

Keithley Manufacturing Code Number 80164 should be

ordered directly from Keitbley Instrumenfs, Inc.

TABLE 6-2.

lain Chassis

PO".?= Supply
Polariry

Board

Thousand Board
Readout Board
osci11acor Board

1neegraeor aoar*
O"cp"f Buffer
Output Buffer

PC-210
PC-210
PC-207
PC-208

PC-229
PC-217
PC-219

PC-218

PC-209

Basing Diagram

following in-

Schematic Part No.

23482E

234baE

23449D
234SOD
2345X
234520
23453E
23457D
23481E
236060

32

0874

MODEL 440

1 Top Cover Assemblv

2

Cover
Fastener

Fastener

3
4
5
6

Aneie. Rack Assembiv
screw, Slotted, 10 - 32
Front Panel

Chassis

x 114

MODEL 440

34

OS74

MODCI. 440

CL201
Cl202

CL203

c1204
Cl?"5

PF

5

10

.0047 F

5QQQ ?F

,F

600 ”
20 ”
6QD ”
?QQ v
20 v

50” ?
600 v
50” v

600 ”
60” v
600 v
400 ”
500 ‘J

50” v

60” ”
5”Q ”
600 v

600 v
600 \’

6804 CS-6‘
5127

EC-10 .cap-l

a-49

! 9

P.EPLAGEABLE PARTS

MODEL 440

MAIN CHASSIS PARTS LIST

"1200" SERIES PC-210

CONNECTORS (Con;'d)

circuit
Desig.

51211 Binding Post, G
J1212 Receptacle, 50 pins, PRINTER/CONTROL

--- Fl"g, mate of .I1212
51213 Receptacle, Microphone, ANALOG OUTPUT

_--

circuit
OesiR.

01201 Silicon
DI202 Silicon
01203 Silicon
01204 Silicon
01205 zener

D1206
D1207
D1208
01209
01210

cannecror

plug, mate of 51213, Supplied

Silicon
Silicon
Silicon
Silicon
Silicon

Description

Type

Mfr.
Code

08811

02660
02770
02660

02660

DIODES

Mfr.

Cc& Part NO.
01295

01295
02735

02735
84970

02735
02735
02735 1X3255
01295
01295 1X645

Mfr.

Part NO.
33-286 BP-15
57-40500-l CS-221

57-30500-1
So-PCZF CT-32

SO-MCZM

Mfr.

1N914 RF-28
lN645 RF-14
lN3255 RF-17
IN3255 RF-17

"R47 W-30

1N3255
lN3255

lN645 RF-14 19

KeiChley Fig.

Part NO. Ref.

cs-220

cs-33

Keifhley

Pare NO.

m-17
RF-17 19
RF-17

RF-14 19

Fig.

Ref.

19
19
19
19
19

19

19

2
3

3

circuit

Oesig.
RI201

R1202
R1203
R1204
R1205

R1206
RI207
R1208

R1209
RI210

R1211
R1212
RI213
R1214
R1215

R1216
Rf217
R1218

RI219
R1220

It1221
R1222
R1223
R1224
R1225

Value

500 k?.

220 0

10 "n

100 kR

1

k0

10 kR

15 kR
100 n
22 kR

18.2 krl
500 0

Not Used

18.2 k!?

4.7 kR

4.7 kQ
680 0

3.3 kP.
100 R
100 n

470 0

15 ks?

1.8 k.Z
560 0
1010 0
109 R

RaeinR

220%. l/4 w

10%. l/4 w
l%, l/2 w
10%. l/4 w
20%,2 w

20%. 2 "
l%, l/S w

10%. l/2 w
10%. l/4 "
l%, l/S w

%20%, 2 "

1%. l/8 "
10%. l/4 "

10%. l/4 "
lO%, l/4 w

10%. l/2 w
lo%,2 "
lO%, l/2 "
lo%, 2 w

230%. l/l w

lo%, l/4 w
lO%,l w
+3-0%,1/R w
+3-0%,1/R w

Mfr. Mfr.

Code
71450

44655
91637
44655

71450

71450 1NS 115
07716 c!.?A
01121

44655 RC07

07716

71450

07716

44655

44655

44655

01121

01121

01121

01121

71450
44655
01121
63060
63060

Part NO.

GC45

RC07

DCF-l/2

RC07

1NS 115

EB

CEA
551

Cl%
RC07
RC07

FCC07
EB
HB
EB
HB

GC45

RC07
GB

Rx-1

RX-1

Keichley Fig.

Part NO. Ref.
RP75-500K

R76-220
RlZ-10"
R76-100K
RPSO-1K

RP50-1OK
RSS-15K

Rl-100

R76-22K

FL**-18.2K
RP72-500
RSS-18.2K

R76-4.7K

R76-4.7K
R76-680

Rl-3.3K
R3-100
Rl-100
R3-470

RP78-15K
R76-l.SK
RZ-560
23093A
230928

19
19

19

19

19
19

19
19

19

19
19

19
19
19

19
19

19
19
19

19
19
19

19
19

36

0874

MAIN cHAss1s PARTS LIST

"1200" SERIES PC-210

RESISTORS (cdnc'd)

RI226
R1227
R1228 1.02 MC!

R1229
R1230

R1231
R1232
R1233
RI234
R1235

R1236
R1237
R1238
R1239
RI240

R1241 1.5 k,?

RI242
R1243

R1244

RI245 1.5 kR 10%. l/4 w

100 R
10 M!,

102 k!?

10.5 kr?

1.05 kc2
105 n
1

kfi

1

kR

1

k?

3.01

k?

301 k::

500 k0

50

ki,

5

k I!

1.5

k!?

1.5 k,?

1.5 kn

OCb
OCb

1%. l/Z w

c20:;/, l/4 Id

f?O%, 2 !4

20'%, 2 14

la::, L/4 w

10%. L/4 "
10%. 114 w
IO%, l/4 w

SWITCHES’

Circuit ielcnle)
oesiq.

s1201 fiorary swirctl, ZERO CHECK 80164 S:;.?iY

__.

Knob Assembly, Zero Check Switch 80164

oescriotion Code

91637
91637
07716
07712
01686

01686

01686

01686
01686

01686

07716

07716

71450
71450
71450

44655
44655
44655
4465 j

44655

AND COX‘TROLS

nfr.

DC-?
DC-1
CEC
CEC

7040

,040
7040
,040
,040

CEC

Type-45

550

1NS 11s

RC37
RCO?
PLO;
RCOl

?3r‘t uo. ie I

14838A

s1202 Rotary Switch less components, RANGE 80164 SF-278

Rotary Switch with components, Range 80164

___

s1203 Rofary Switch, DAI!PING (see 3150 R1221) 71450 3?7S-l3Z

___

s1204 P\ot;Lry switcn, OISP'AY RATE (see also

___

Switch
Dial Asse-nbly, Rnny Switch

Knob Assembly. Damping Control

Rl201)
Knob r\ssembly, LkJlay Race Control 80164
Screwdriver Adjust, ZERO Control (see

8016‘

80164

71453 RP75-50%

71450 RP72-500

2303;s

21384A

11384‘!

R1211)

TR4NSISTORS

circuit
oesiq.

Mfr.

Code

Ql?Ol 80164

Q1202

Q1203

91204 07263
?1205

80164

Oi263

04713

Q1206 71279

** Transisrors Q1201 and Q1202 are marched

and

should be

ordered only as Keithiey Part Number 218508.

0874

37

REPLACFABLE PARTS

MODEL 440

POWER SUPPLY PARTS LIST

("100" series, PC-210)

Circuit
Desig.

Cl01
Cl02
Cl03
Cl04
Cl05

Value
2000 &n

100 pF

150 pF
200 W-F
200 pF

Rating
15 v

600 "
600 Y
35 v
35 v

Type

EAl

CerD
CerD
EAl
IL41

Mfr.

Code

72982
72982
90201
90201

Mfr.

Part NO. Part NO. Ref.

36-750-2000-15C C93-2000M 19
ED-100 c22-IOOP 19
ED-150 c22-15OP 19

MTV200N35PDN C177-200M 19
MTVZOON35PDN C177-200M 19

Keirhley

Fig.

Cl06 200 LIF 35 " EA1 90201 WlV200N35PDN C177-200" 19

Cl07 200 pF 35 v EAl 90201 MV200N35PDN C177-2OOM 19
Cl08 1.2 +LF 20 " ETT 17554 TSDl-20-125 C179-1.223 19
Cl09 5 PF 600 " CerD 72982 ED-5 c22-5P 19
Cl10 100 LIF 15 v ETB 73445 C426 c3- 1OOM 19

Cl11 100 PF 15 v
Cl12 15 UF 300 v
Cl13

Cl14 68 pF 500 v

Used on Model 445 only

ETB
!%A1

HICA

13445
90201

84171

C426 C3-100M 19
PTC015-N300-P3E C173-5M 19

DMl5-68OJ CZl-68P 19

DIODES

Circuit
Desip.

Mfr.

. Code

Mfr.

Parr No.

Keichley

Parf No.

Fig.

Ref.

DlOl Silicon 13327 IN4139 SF-34 19
D102 Silicon 13327 IN4139 w-34 19
0103 Silicon 01295 lN645 SF-14 19
D104 Silicon 01295 IN645 RF-14 19
0105 Silicon 01295 1N645 RF-14 19

DlO6 Silicon 01295 lN645 RF-14 19
D107 Silicon 01295 lN645 RF-14 19
DlOS Silicon 01295 lN645 RF-14 19
D109
DllO

Dill
D112

D113

Silicon

Ze"er

Silicon
Silicon

Not Used

lN645
IN936

02735 IN3255 RF-17 19
01295 lN645 RF-14 19

HISCELLANEOUS PARTS

circuit
Desig. Description

FlOI (117V) Fuse, slow blow, 3/0 A

Mfr. l4fr.

Code Part No.
71400

Type MDL FU-18 3

Keiehley

Fig.

Part No. Ref.

FlOl (234V) Fuse, quick acting, 200 WA 75915 361.200 F"-24 3

--- Fuse Holder 75915 342012 FH-3

PlOl Cord Set, 6 feet 93656 4630-13

SlOl
s102

TlOl Power Transformer 80164

Slide Swiech, 117-234"

80164

Toggle Switch, POWER 80164

SW-151

SW-265
TR-114 TX-114 16

co-5 3
SW-151

SW-265 2

3

38

0874

MODEL 440

POWER SUPPLY PARTS LIST

"100" SERIES, PC-210

RESISTORS

RIOI
R102
R103
R104
R105

It106
RI07
R108
RI09
RllO

6.8 k?

0.2 0
10 k0

1.1 k*
I

kR

100 n
150 0

kn

13

1 n
680 n

Rlll 3.3 k:'.
R112

4.7 k0

‘0%. 114 w

kiO%., 4.25 W

lL, l/8 w
I%, l/8 w
lO%, l/4 w

l%, l/8 w
l%, l/8 W
lo%, 114 w
l%, 1/2 w

lO%, l/4 w

10%. l/4 w
lo%, l/4 w

Rll, 3.3 k?. lo%, l/4 w

RI14
R115

R116
RI17
R118
R119

R120
RlZ1

It122
RI23
R124
RI25

4.75 k9

2 k0

8.06

k9

19.2

kl

7.5

k(l

31

kc

3 .?

33 kR
33

k?.

7.5

k.".

a2 n

1

MI!

l%, l/8 "

20%, 2 w

1x., l/8 w
1%. l/8 W
l%, l/8 w

lo%, l/4 w
I%, l/2 w

lO%, l/4 w

10%. l/4 w
l%, l/8 W

10%. l/2 w

10%. l/4 w

44655
91617
07716
07716

44655

07716
07716

44655
91617
44655

44655
44655
44655
07716
71450

07716
07716

07716
44655
91637

'44655

44655
07716

01121
44655

Mfr. Kcichley

Fig.

Part No. p.lrc NO. hi.
RCO 7 R,6-6.81;

CL-2
CEA
CEA

R15,-0.2
R88-LOK
R88-1.1);
R76-1K

CW
CEA

REJ-100

RES-150
KC07
DC-l/2

RCOi

RC07

RCOi

RC07

Rib-3. IK

RTb-‘. is

876-3.3X
CEA

INS 115

CL,
cm-TO-18.2kZ
CEA
SC07
DCF-I,2

R88-8.06):

R88-lS.2i;
R88-7.5x

R76-3x

RI'-,

RCOi

RC07

CEX
EB
RCO 7

QlOl

4102

Q103
Q104

QlO5

QlO6
9107

Q108

Q109

QllO

0111
$12
4113

9114
9115

100 k9

56

kR

80.6

kc!

7.32

k.1

1.5 k9
I kc?

12

k::

10

kc!

I _

10%. 114 w
lO%, l/4 w
I%, l/2 w
L%, l/8 W
IO%, l/4 w
10%. l/4 w
LO%, l/4 w
lO%, l/4 w

44655
44655
07716
07716
44655
44655
44655
44655

RCO7
RCOi
CEC
CEA
RCOi

RCOi

RCOi

RC07

TRANSISTORS

02735

71279
07263

07261

07263

07261
02734
07261
07261
07263

02734 40319 x-50 IS
07263
07261

07261
07263

2N5181
ES-532I

21111565

2X3565
Sl7638

2N3565
40117
2N3565
2N3565
517618

S17638
517638
2N3565
2Nl565

X-6.9 19
K-54 10

K-19 19

n-39 19
TG-11 19

x-19 19

x-43 19
K-19 19

K-19 19

K-31 19

K-13 19

m-13 19
E-19 19
TG-19 19

0874

39

POWER SUPPLY PARTS LIST

"100" SERIES, PC-210

TlbwSISTORS (conc'd)

circuit
DeaiS.

Ql!"

Qlli
Q118
Q119
QL20

c 2 ..I i

CI".

150 pf
150 pF

60" i:
60" 3'

Mfr. Mfr.

Code Part NO.

07263
07261

02735
02735
07263

tern
cero

INTEGRATED CIKCUiTS

72Y82
72982

!+fT.
Code Parr lo.

­04TLl

04;11

04i11
04713

SL7638
517618

40346
40346
2Nl565

ED-150

ED-l.50

>,fr

>!C89OP

!X824P

XS24?

X824?

Keithlry

Pracc NO.

X-31
K-11

x-44
x-44
K-39

CIZ-!50? li

C21-15OP 17

-

04711

04713

047l3 XYYO?
04713
04ill

O&i11

XC89OP
?KSSEP

?!CS~OF

?!CY14?

XY89P

ic-8 17
IC-8

IC-3 17
ic.7

17

*;

MODEL 440

REPIACEABLE PARTS

READOUT Fi‘MRD PARTS LIST

“400”

SERIES, PC-229

INTEGRATED CIRCUITS (conr'd)

XODEL

440

circuit
DeBin.

Q.4411
QA412

QA413
QA4i4
QA415

Q.4416

QA417

circuit
msi2.

"401

“402
“403

Circuit
Desie.

R.401

R&O?
R403

Descriotio"

Dual J-K Flip-Flop
Dual J-K Flip-Flop
Dual J-K Flip-Flap
Dual J-K Flip-Flop
Decimal Decoder/Driver
Decimal Ileccderh-iver
Decimal Decoder/Driver

Descriocion

Units

Readout

Tens Readour

Tube

Tube

Hundreds Readoue Tube

Mfr. Mfr. Reithley Fig.
Code Part NO.

04713
04713
04713
04713 MC89OP
07263 “6B996079.x
07263
07263

MC89OP IC-8
MC89OP
MC89OP

"6B996079X

U68996079X

Part NO.

IC-8
IC-8
IC-8
IC-3

IC-3

IC-3

READOUT TUBES

Mfr.

Code

83594

83594
83594

Mfr.

Parr No.

85750
85750

85750

Reithley

Part No.

w-5750
EV-5750
w-5750

RESISTORS

Mfr.

Code

01121
01121

01121

Mfr. Keichley rig.

Part NO. Part NO. ?dL.

EB
EB
EB

R19-10K
x19-1.m
R19-1DK

Ref.

24
24
24
24

24

24

24

Fig.
3ef.

24

24

24

4

2‘
24

OSCILLr\TOR BOARD PARTS LIST

(“500” Series.

circuit
Desiq.

C5OL
CjO2

c503 4.5-25 IF 500 v
C504

c505 470

va 1ue

.0022

,001

:tF
;rF

Ratine
100 v

100 v

CerTrimer

22 QF 500 v Mica

pF

600

V CerD 72982

C506 220 pF 600 'J Cer"

c507

C508

56 & 15 ”
10 :rF 20 v

ETT
ETT 17554

M1SCELLmE00S PARTS

Descrioeion

D501 Diode, Silicon
D502 3ide, Silicon

0503

3iad.z. Silicon 012c5

J501 c i'sed

QA501

Quad 2 input cnee
QA502 Quad 2 Ia?"c Gate
Y501 Crysral,

60

Hz

Crv*Ca!, 50 RZ

PC-217)

CAPACITORS

Mfr. nfr.
Code

13934

13934
71590 8OWZ C76-4.5-25P

84171

72982

17554

Mfr.

Code

01295
01295

04713
04713 NC824P
80164

8OL64 CR-2

Parr NO. Parr NO. Ref.

E3FR-222-1-C C152-.0022M

E3FR-222-1-C c152-.OOlM 20
DMl5-22OJ c21-22P 10

ED-470 c22-b7OP

ED-220 c22-2?OP 20

CC201556610

TSDZ-20-106 C179-IO”

Mfr.

Pal-c NO. Part NO. hi.
1x645 RF-l‘ 10

1X645 -W-I‘ 20

IN914

HCZZLP IC-5 20
CR-1 cxi- I 10

Keithley Fig.

20
20
20

C234-56M

20
20

Keithley

Fig.

W-1‘ 20

IC-5 10
CR-2 20

42

MODEL 440

KS01
CO?
R503
R504
KS05

R506

R507
R508
R509
R510

R516
R51i
R5L8
R519

R520

R521

R522
R523
R524
R525

R526

R52,

R528
R529
R530

3.3 k.:
33 k!

68.1 ~:

4.99 k.2
1

k:l

1 k
1

k:

470 ';

4.7 k!

56 k

4.7 kj

470
680 .:
470 ,:
23,

1

k'

4.99 k

56 k'.
23,

1.3 k::

lo::. l/4 w
l%, l/8 w
10%. l/4 w
lO%, l/4 Id
lo%., l/4 w

10%. l/4 w
10%. l/4 I4

IO%, 114 14
10%. 1/4 li
lO%, l/4 w

44655
44655
0,716
0,716
44655

44655
07716
44655
44655
44655

44655
44655
44655
44655
07716

0,716
07716
44655
07716
IA4655

44655
44655

44655
44655
‘4655
44655
44655

RC07
RCOi
RCD,

RCD7
FCC07
RC07
KCDi
CL!

CL\

CEA

RC07

KC07
RCOi

RC3i
RCO 7
RCO7
RC07
RC07

Rib-3.lK
F.76.I,):
K88-68. i

R;b-iK
R‘&iOK

R:6-!h 20
R?6-3,s 20
R:6-,.9K

3.6.33c 20
!i76-1.5x

20
20

20
20

R531
R532
R533
R534
57535

R536

KS17
R538

CirC"iC
Oesie. Code ParL No. Part No. Ref.

Q501 07263 2x5134 X-65 20
9502 07263 2x5134 TG-65 20

qso3 0,163 ZNjllS TG-65 20
9504 0,263 295139 X-66 20
Q505 07263 2NS134 X-65 20

Q507 0,263 2!?5134

4508 0,263 2X5139 K-66 20

0509 0,263 2x5134 K-65 20

0510 07161 2x5134 Tt-65 20

Eli74 41

5.6 k.?
10 k.!

10

k;!

1.3 k!
100 ::

47 R
33 !1

4.02 k~l

10%. l/4 w
lO%, l/4 w
lO%, l/4 w
10~~, l/4 w
1%. l/8 W

10%. l/4 w
lo%, L/4 w
l%, l/8 W

44655
44655
44655
44655
0,716

44655
44655
0,716

TRANSISTORS

Mfr.

RCOi
RCOi
RCOi
RCOi

CM

RCOi
KC07
CEA

Mfr. Keithiey

Rib-j.6K
%:6-101:
R:6-10 20
Rr6-l.sK 20
RBS- 100

Rib-47 20
R76-31 20
K88-4.0X 20

TC-65

20
20

20

Fig.

2"

OSCIL.LATOR BOAR0 PARTS LIST

“500” SERIES PC-217

TRANSISfORS’(cont’d)

CirC”iC

oesip.

Q5ll

Q512
Q513
(1114

C602
CbO3
CbO4
C605

CbO6

COO7
C608
C609
CblO

C611
Cbl?

C613
Cb14

xoc USed

not Us.4

100 DF bO0 "

500 ”
100 v

20 v
600 v

600 v
600 V
250 "
20 "
1000 v

250 "
20 "

20 v
10 ”

Mfr. Mfr.
Code Pare NO.

07263 2N5134
03508 2N2646

INTEGRATOR lNxR0 PARTS LlST

("600" Series, PC-219)

72982
71590

13934
17554 TSD2-20-106

72982 ED-220
72982 ED-220

72982

73445
17554

56289

73445
ET-7
El-r
El-7

17554

17554
17554

Keirhley Fig.
Part NO. Ref.

TG-65 20
TG-52 20

ED-100 c22-1OOP 21
cm-1OJ
E3FR-22-1-C

ED-.0047
C280AElPlOOK
TSD2-20-106
5GAQ22

C280AEIPlOOK
TSDZ-20-106
TSD?-20-106
TSD?-10-226

C138-IOP
c152-.082X
C179-10M
C22-22OP

C22-22OP
C22-.0047H
C178-.,M 21
C179-10M 21
C72-22P 21

Cl78-.lM 21
Cl79-IOH 21
ci79-1OM 21
c1*0-2211

21
21
21
21

21
21

21

0601
0602
0603
0604
0605

44

zener
Ze"er
SiliCO"
SiliCO"
Silicon

04713 IN936
04713 lN936

07263 2x3565

07263 2X3565
01295 lN645

02-j 21
m-5 21
TG-39 21
TG-39 21
w-14 21

0874

MOOCL 440

INTEGRATOR BOARD PARTS IJST

"600" SERIES, ~~-217
INTCCRATED CIKCUITS

QA601
QA602
QA603
QA605

R601
R602
R601
R604

R605

R606

Rb07

R608
R609
I7610

Rbll
R612
R613
R614
R615

Mfr.
Code

l”CegrJCed circuit

Integrafed circuit 12040

High Speed Differential Comparator

Quad 2 Input Gaee

12040

07263
04713

RESISTORS

Mfr.
Code

7.5 k:l

7.5 k:.

7.5 kl!

10 k.!

"

7.5 k.:

7.5 k:!

7.5 k.;

10 k.A
10 ki?

camp
Me
MfF
MC
MC

cermet

MtF

MfF
MC

MC

cermet
camp

44655
91637
07716
07716
07716

73138
91637
07716
07716

07716

73138
44655

Nat Used
499 71

49.0 k:1

MCF

iler

07716 CEA
91637 ?OF-:,B

Mfr.

cart NO.

IX-201 ic-2
M-201

U5B771039X xc-4

MC824P IC-5

Mfr. Keithlev

Part NO.

-

RC07

M-l/8
CE.I

CEA
CEA

77PRlOK

Km-l/8

CEA
CEA
CEA

77PRLOK
RCOi

Keithle!

Parr NO.

IC-2

Part x0.

Rib-lOK
R,,;.::

R88-7.51:
R88-7.5X

R88-7.3

RP64-*ohi

R76-10K

R6i6
K617
R618
R619
R620

Rb21

R622

R623
R624
R625

R626

R627
R628
R629

R630

R631

R632

R633

R634

R635

R616

R637

R638

R639

R640

680 ‘2

680 .1
33 k

4. 7 k..

33 k:!

4.7 k::

4.7 k!

4.7 k::

49.9 lir:
100 !Lr

237 )
301 k::

47 ::

100 k:? lO%, l/4 w
158 ?

158 I!

200 !

301 k.?

1.5 k:!
47 9

IO%, l/4 w
IO%, II4 w
lo%, 114 w

l%, l/8 W
10%. l/4 w

I%, l/8 w
I%, 118 w
lo%, l/4 w

:%, l/8 w

1%, l/8 W

,foz, 314 w

lL, l/8 W
101-, l/4 w
10%. l/4 w

I”%, l/4 w
10’7”. 114 w

lo%, l/4 w
10'%, 114 w

ioz, 114 w

COlllp
camp
CDmp
Camp
camp

camp
C0mp
camp

MC

camp

NtF
MCF
camp
camp
MtF

MCF
cermer
NfF
camp
camp

CO”p
camp
camp
C‘xlp
camp

44655 RC07
44655
44655
44655 RC07
44655 RC07

44655 RC07
44655
44655
91637
44655

07716 CEA
07716 CEA
44655 RCO7
44655
07716 CEA

07716
73238
07716 CEA
44655 RC07
44655 RCO,

44655 RCO7
44655
44655
44655
44655 RC07

RCOi
RC07

RC07
RCO,
?NF-118
RCO,

RCO,

CEA

77PRZDO

RCO,

RCO,
RC07

Rib-683
Rib-680
R76-33K
R76-i. x
Rib-,X

R76-4.z
Rib-b. x

R76-4.X

In,;-49.91;

R76-LOOK

R88-237
R88-301X

R76-47

R76-!OOK
R88-158

R88-158

REW-200
R88-301K
R76-i.5K
R76-4:

R76-?.21(
R76-l.7
R76-47
R76-1.5K
R76-1.X

0874

45

niTEGRATOR 8OAlw PARTS l.IST

"600" SERIES. PC-217

RESISTORS (cont'd)

Ci-X"it
oesig.

R641
R642
R643

R644

R645

R646

R647

R648

R649
R650

R651

R652

R653

R654

R655

R656

R657

circuit

_

“eSLq.

Q601
0602

,---

Q603
Q604
Q605

Value

100 .­10 1

3.01 k.2
1 kl

5.6 k?

5.6 k.:
10

402 ‘:
200 :
402

‘:

10 k.:

6.98 k.l

6.04 k:

Mfr. t4fr. Keichley Fig.

bEi"R Type

lO%, l/4 w
IO%, l/4 w

1%. l/8 w

1%. l/8 "

IO%, l/4 "

IO%, l/4 w
LO%, l/4 w
I%, l/8 W

lO%, l/4 w ComP 44655
10%, l/4 " camp 44655

lO%, l/4 w
10%. l/4 w
10%. l/4 w
l%, l/8 w

l%, l/8 W "t.F 07716

camp

ComP 44655
neF 07716
MCF 07716
camp 44655

camp 44655
camp 44655
WCF 07716
cermec 73138
MCF 07716

camp 44655

camp 44655

camp 44655
MfP 07716

code

44655

TRANSISTORS

Code

07263
07263

04713

Part NO. Part NO. Ref.

RC07 R76-100
*co7 R76-10
CR.4
CEA R88-lK
RC07

UC07
RCO7

77PR200

CEA

RCO7
KC07 Rib-820

RC07 R76-2.2K

RC07

SC07

CEA
CEA

Part NO. Par: NO.

2N5139 K-66
2N5139 X-66

2N4220 E-&2

R88-3.01K

R76-5.6K

R76-5.6K
R76-10

X88-402

RP64-200
R88-$02

R76-3.x

R76-220
Ri6-1OK
R88-6.9Vi
R88-6.04K

Keithley

Fig

Ref.

21
21
21
21
21

21
21
21
t1

21

21
21

21
21
21
21
21

21

31

21

RIO01

MO02 3.9 k3
RICO3
R1004

46

18G k:?

120 k!i
10 kil 10%. l/4 w

lO%, 1/4 w

lo%, l/4 w
HI%, l/4 w

camp

Como

camp

COmp 44655

44655
44655
44655

RCOi

RC07

RC07
RC07

*\;i-l8oK

%76-:.%

26
26

0874

‘L,.
Re i

25
?i

12" k :

10 k'

180 k.l

2.2 Iv:
1 k:!
1" k:1

Rllll

RI112

6.98 k:.

6.04 k.!

K1116 2 k,!

12” k’.!

LO !c:

180 k!,

3.9 kn

0874

camp
cum,,
corn*

MU
MO

44655
44655

44655

44655

44655
44655
44655
44655

44655
44655
44655

“771”

"7716

RC37

KC07

RCOi
KC07
RC07
RCO?

RC07

KC07

RC07
CEA
cc.,

07716 CL\

44655

KU7

44655 KC"7
44655 RCO7
44655

RC07

R;h-,K

R76-3.3K

R76-iK
R76-,.,K

8.76.12OK

R76-IOK

RYb-L80K
R76-2.2K
R76-1K
RiS-LOK

R76-L?OK
Rib-L80K
R76-2.2X
R88-b.981:
R88-6.041;

R88-1K
Ri6-LZOK

Ri6-1OK

R76-180K

R76-3.9K

47

REPLACEA8L.E PARTS

WOOEL 440

MODEL 4401 OUTPUT BUFFER PARTS LIST

"1100" SERIES, PC-209

TRAiwISTORS

Circui?
Desig.

91101
QllO2
01103

$104

Q1105

Q1106

Q1107
QllOB
QllOS
QlllO

Mfr.

Code Part NO. Fart NO.
07263

07263

Not Used

07263
07263
07263
07263
07263

NOTE

mr Keithley

2N3565
2N3565

TG-39
TG-39

TG-39
TG-39

2N3565 TG-39
2N3i65 TG-39

2N3565 TG-39
2N3565 TG-39
2N3565

TG-39

On schematic diagram 23481E there are 6 buffers labeled 'A' through 'F'. Each buffer Ls composed of

5 resistors and 3 transistors.

A sample buffer circuie is given on the schematic. Following is a

sample replaceable pars lisf for each buffer.

BUFFER RESISTORS (A chru F)

circuit

Desi*. Value RClfi"<

TVCX? Code Part NO.

nfr. z+fr.

Keithley Fig.
Part No.

Fig.
Ref.

25

25

25
25
25
25
25

Rei.

RI121 10 k:; 10%. l/4 w camp 44655 RC07
81122
RI123
a1124
R1125

Circuif

lksis.
Qllll

Q1112
Q1113

120 kl lO%, r/n " Gmp 44655 RCO7
10 k?
180 k.:

3.9 k.3

lO%, l/4 " Gmp
lO%, l/4 51
lO%, l/4 w

ComP

CQ=P

BLETER TRANSISTORS (A chru 3)

44655 RGO7
44655 RC07
44655 &co7

Mfr. XfZ.

CNk Pat-t NO.
07263

07263

07263

2N3565 TG-39
2N3565
2113565 TG-39 25

R76-10K 25

R76-120K

25
R76-10K 25
R76-l&0:< 25
R76-3.9K 25

KeiChley

Fig.

Part NO. Ref.

25

TG-39

25

48

0874

co&? List of suggestrcl Manufacturers

1121 Allen-Br3dley Corp.

1201 sovti, 2nd street

>*ilwa”kec, wis.

53204

1295 Texas Insrrumcnts, Inc.

Semico"d"cro~-Compo"encs Di".

13500 N. Central Expressmy

Dallas, Texas 75231

1686 RCL Electronics, Inc.

195 McGregor street

Elanchester, N.".

03102

2660 Ammphenol Eleceronici, Corp.

2801 souctl 15th Avenue
3roadview, 111.

60153

2734 Radio Corp. of America

Defense Electronic PraducCs
Camden, New Jersey

2735 Radio Corp. of America

Commercial Receiving Tube 61
Semiconductor Division
Somerville, N..J.

3508 General Electric Company

Semicanductor Producri Lk?f.
Electronics Park
Syracuse, New York 13201

4i13 Xotorola Semiconducror

PraducLs, 1°C.

5005 Zasf NcDawell Road

Phoenix, Ark. 85008

5397 Union Carbide Corp.

Elecr:o"ics Division

270 Park *venue
New York, New York 10017

7263 Fairchild Camera h InstrumenC

Corp., Semiconductor Division
313 Francage Road
tiuntain View, Calif.

7716 IRC, Inc.

2850 Mt. Pleasant
Burlington, Iowa 52601

9922 Burndy Carp.

Richards Avenue
Norwalk, Corm. 06852

2040 ?lacio"al Semiconductor Corp.

Camerce Drive

POST Office Box 443

Danbury, CO"". 06813

13327 SaiiLro" Devices, 1°C.

56 Oak Tree ROeId
Tappan, New York 10983

13934 xidrrec Corp.

602 Noin

0si,kash, Nebr. 69151.

246Sj General Radio Ca.

22 Baker .A"e""e

!Gest Concord, mss.

01781

27682 Hathaway Insrrumencs, inc.

5800 E. Jewel? Avenue

Denver, Colorado 80222

44645 Ohmite Mfg. Co.

3631 Howard Street
Skokie, Illinois 60076

56289 Sprague Electric Co.

SOTCh Adams, Nass.

58474 Superior Electric Co., The

383 Yiddle Street
3risto1, CO"". 06012

71279 Cambridge Themionic Car?.

430 Concord *venue

Cambridge, Mass.

i1400 Bussma"" blfg. Lx". of

McGraw-Edison co.

2538 W. Oniver~icy Street

St. Louis, MO.

71450 CTS Carp.

Il42 14. Beardsley h"en"e

Elkhart, Ind.

71590 Cenrralab Division of

Globe-Union, Inc.

932 E. Kt?efe *venue

xilwaukee ) wis. 53212

72981 Erie Technological

Producci, 1°C.
6LL 5. 12th Street
Erie, Pa. 16512

7,445 *\mpereu ELectronic CJ., Di”.

of North American

Philips Co.

Hicksvilie, N.Y.

73690 Elcn Resistor Co.

1158 Broadway

New York, New York

8359‘ Burroughs Corp.

Electronic ComDonenLs Div.

Post Office 30x 1226
Plalnfieid, 9.J. 07061

Y&171 Arc0 Electronics, Inc.

Corlmu"iry Drive
Great Neck. S.Y. 11322

84790 Durn Car?.

Inpiezxnc Div.-P.O. 30x 23i

Zanesville, Ohio GiO?

90201 Mallory capacitor

3029 West Uashin*Con
POSC Office BOX 372
Indianapaiis, Ind.

46106

91637 Dale Electronics, Inc.

Post Office Box 609
Columbus, Nebr. 68601

91662 E2co Corp.

Wiliow Grove, Pa.

91802 Industrial devices, Inc.

982 River Road

mcpwacer, New jersey 07020

93656 Electric Cord Co.

1275 Bloomfield Avenue

Caldwell, N.J.

95712 Dnge Ele;r;i; Co., I";.

Hurricane Road
Franklin. Indiana

0876

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SHIP IXSTRU?lEXT 5 FOIGI TO:
SALES SERVICE DEPT.
KEITHLEY INSTRL?lENTS, INC.
28775 AURORA ROAD

CLEVELAND, OHIO 44139

PESSOS USING THE ISSTRC\LEST:
NX\IE
COXPANY

ADDRESS
CITY

STATE ZIP

PHO>X

Describe problem and symptoms using quantitative data whenever possible (enclose read-

w ings, chart recordings, etc.)

16.1 L'

1st and describe ail other eauimenr used in the experinenc.

Give control setzin;s

CN440-3

KEITHLEY INSTRUMENTS.

INSTRUCTION MANUAL

CHANGE NOTICE

MODEL 440 DIGITAL PICOAMMETER

INTRODUCTION:

duct performance and reliability,

to Instruction Manuals to reflect these improvements. Also, errors in

Instruction Manuals occasionally occur that require changes. Sometimes,
due to printing lead time and shipping requirements, we can't get these
changes immediately into printed Manuals.
formation is supplied as a supplement to this Manual in order to provide
the user with the latest improvements and corrections in the shortest
possible time. Many users will transfer this change information directly
to a Manual to minimize user error. All changes are underlined.

CHANGES:

(1)

Page 46, Replaceable Parts, TRANSISTORS, change Q607 and Q608 to
read as follows:
Q607, N-Channel FET (Selected TG-71), 01295, TISiO, w, 21
4608, N-Channel FET (Selected TG-711, 01295, m, TG-40", 21

*Order as a matched pair, Keithley Part No. Tm

Since Keithley Instruments is continually improving pro-

it is often necessary to make changes

The following new change in-

INC.

Page 44, Replaceable Parts, CAPACITORS, change C602 to read as

(2)

follows:
C602, ~JF, 2OOV, Poly, 00686, E1013-1, C31-5P, 21

Page 36,

(3)

01203
D1204
D1206
D1207
D1208

Page 38, Replaceable Parts, DIODES, change as follows

(4)

Dill

Replaceable Parts,
Rectifier, lA, 800V MOT
Rectifier, lA, 800V
Rectifier, lA, 800V

Rectifier, lA, 800V
Rectifier, lA, 800V

Rectifier, lA, 800V

DIODES, change as follows:

lN4006 RF-38
MOT lN4006
MOT lN4006 RF-38
MOT

MOi lN4006 RF-38

MOT

lN4006 RF-38

lN4006 RF-38 19

RF-38

19
19

i:
19