Tektronix 503 Instruction Manual

INSTRUCTION MANUAL

MODELS 503, 503C

MILLIOHMMETERS

PRINTED MAY 1977, CLEVELAND, OHIO, U.S.A.

MODEL 503

CONTENTS

Section

Page

SpECIpIC*TIONS ---------------------------------------------------- iv

GENERAI, DESCRIPTION ________-___________----------------------- 1

1. OpE&Q-ION ----------------------------------------------------- 2

2. CIRCUIT DESCRIPTION ------------------------------------------- 12

3.

SERVICING -_-_------------------------------------------------- 18

4. REpL)&E&LE pm',-- ____-___________________________________-----

5.

SCHE&yJIC --------------------------------------------------------- 31

24

ii

0874

MODEL 503

Pip;.

ILLUSTRATIONS

No. Title

1 Front Panel. ---------------__----------------------------

ILLUSTRATIONS

Page

1

2 Pour Terminal Measurement. -------------------------------3 Model 503 Controls. -_--__________-_-_-___________________

4 lbo-terminal Connection. ------_-_-_________-_____________ 5 Modification for &ground Chassis. -----------------------6 Series Resistance Measurements. ----------_---______------

7 a 9 Super Regulated 12 Volt Supply Schematic Diagram. ---------

10 Test Current Generator Schematic Diagram. ----------------11 AC Amplifier Schematic Diagram. _--_________-__--_________ 12 Synchronous Demodulator Meter - Output. _-______---_-______

13 14 15 Location of Printed Circuit Board Components. ------------

16 Location of Range Switch Components. ---------------------

Exploded View for Rack Mounting. ------------------------Power Supply Schematic Diagram.

Waveform of Synchronous Demodulator. ----------------------

Model 503 Internal Components Locations (Top Removed). ----

------------_---__________

2 5

6 7

9

11 12

13 14 16 17

19 21 22

23

0874

c

iii

SPECIFICATIONS

MODEL 503

SPECIFICATIONS

Applied C”Wl?“t,

RANGE,

oIlIll* rnls rms

0.001 100 100 10.0

0.003 33.0 100 3.3

0.01 10.0 100 1.0

0.03 3.30 100 0.33

0.1 1.0 100 0.10

0.3 0.33 100 0.033

1.0 3.0 3000 9.0

3.0 1 .o 3000 3.0

10 0.30 3000 0.9

30 0.10 3000 0.3 100 0.03 3000 0.09 300 0.01 3000 0.03

1000 0.003 3000 0.009

ACCURACY:

Meter: * 1 % of ‘“,I SCSI0 an a,, ranges. Output Te,lni”al*: +0.5% Of ‘“II SC& an a,, ranges.

Nom Less U’S” 1% Brmr ts added I” measuring 9amp1e. with B series resctanca Of 2% Of “ample m.i.l.“E.. ZERO DRIFT: None. WARM-UP TIME: 15 minutes.

INPUT ZERO: Lever ~wifch prevenf~ off-scale meter indications while changing samples.

Rl8E TlME 110% to 90%): 0.25 second an a11 wmges. SAFETY: Maximum power dissipation in sample with improper range setting is 80 milli-

wets. Maximum dissipation cawed by instrument component failure and improper range

sating is 160 milliwatts. REPEATABILITY: Within 0.25% of full-scale range setting. CALIBRATION: Internal redstance standard for calibration with front panel controls.

RECORDER D”TPwr

Output: + 100 millivolts dc at full scale.

Output Resistance: 800 ohms.

Noise (above IO Hzl: Less than 1 millivolt rms. CONNECTORS: Test Leads: Cannon XLR-3-32. Output: Amphenol 80.PC2F.

POWER: 105-I 25 or 2 1 O-250 YOltS, 50-1000 HZ. 30 watts. DIMENSIONS, WEIGHT: 5%” high x 17%” wide by 13%” deep; net weight. 18 Ibs.

ACCE88DRlES 8”PPUED: Model 5031 Current and Voltage Leads; mating o”f,,“t con-

“eCtOr*.

milliamperes

Voltage

Drop.

microvolts in Sample.

ME2tdll”~

Dissipation

miorowatts

iv

0874

MODEL 503

GENERAL DESCRIPTION

SECTION 1.

The Model 503 Milliohnuwter permits rapid, accurate, low resistance tests.

ruggedness and ease of operation not possible with bridges. tly on a mirror scale meter.

and the instrument is not damaged by overload. Features include: 13 full-scale ranges from 0.001 to 1000 ohms; accuracy of +l% of full-

scale meter indication and ?0.5% of full-scale output voltage; no zero drift; rise time of 0.25 second to 90% of final value;

millivolt dc output for chart recordings or control functions; The measurement technique involves an ammeter-voltmeter method using an ac test current. Typical uses include measurements of internal resistance of dry cells, resistivity pro-

files of thermo-electric materials; circuit testing of contacts,

Balancing is unnecessary,

and safe measurement of fuses and squibs.

GENERAL DESCRIPTION

It combines a

Measurements are read direc-

calibration stability is excellent,

sample dissipation of less than 10 microwatts; lOO-

and front panel calibration.

measurements of temperatures with thermistors; dry-

0273

OPERATION

MODEL 503

SECTION 2.

2-1.APPLICAl'IONS: The Keithley Model 503 Milliohmmeter is especially useful

for accurate measurement of low value resistors; resistances of lead wires, terminal connector contacts and welds; resistance change in conductors due to temperature and humidity effects; conductors; resistivity of semiconductors, contact resistance of vibrators, relays and choppers and internal resistance of dry cells. Also for resistivity profiles of thermoelectric materials end safe measurement of squibs and fuses.

2-2.MEAsuRBMERT TECHNIQUE:

Red

0

w.

Current

Leads

*

0

Black

Figure2

of the sample (Section 2-18) although in most cases at 40 cps testing frequency this is negligible.

are eliminated and very stable high sensititity measurements can be made so that with this AC method sample dissipation can be held 10 microwatts in measuring

a 1 milliobm sample. A typical dissipation on a D(: Kelvin Bridge is 1 watt for the ssme measurement.

However, with an ac exciting test current, thermal E?@'s

!Che Model 503 measures resistance by an metervoltmeter method using an ac test current. Four terminals are employed; two furnish a known test current to the sample and two measure the

resultant voltage drop.(Fig. 1) !Che voltage is

3

measured by a synchronous ac voltmeter sensitive

only to the test current frequency.

Most Kelvin resistance methods employ dc current

to measure resistance. !l%is method has the advantage of measuring only the resistive portion of the sample.

low resistance being measured either extremely

high currents must be passed through the sample

or very high sensitivity dc voltmeter techniques

must be used to measure the voltage drop across

the sample.

0

(which is the more cosnnon) excessive heating and damage to the sample msy occur. If high sensitivity LX voltage measurement is used, extreme inaccuracy may occur because of thermal EKF's and other spurious dc disturbances. With the AC

method used in the Model 503, there exists some

possibility of error due,to the reactive component

OPERATION

resistance of ohmic junctions in semi-

However, due to the extremely

In the case of-high current operation

2

2-3.ACcuRACY:

factors. These are discussed in Section 2-18. is within 1% of full scale for meter indications and 0.5% for full scale output voltage.

The accuracy of the measurement can be dependent on several

The basic accuracy of the 503

0273

MODEL 503

2-4.RRPEATABILSl'Y: Raving once established a reading for a particular sample measurement, it is possible to repeat within 0.25% of the full scale range setting. This assumes the connections to the sample remain fixed.

OPERATION

2-5.CALIRRATION: The

resistance standards to check its accuracy.

503

is self calibrating and thus reduces the need for

It is possible to verify the cali-

bration with or without the sample attached to the test leads. (See Sect. 2-14)

2-6.VOVIMETER SPECIFICATIONS:

Since the

503

uses a synchronous demodulator, the voltmeter is sensitive only to signals of the test current frequency. The sensitivity and input impedance are listed in Table 2.

TABLE2

Rms Input for Full

Remges

Milliohm

Ohm

Scale Deflection

100 uv

3000

uv

2 in

200

ohms

1 x 106 ohms

2-7.TRST CURRENT CRARACTRRISTICS: The testcurrent is a square wave derived from the transistor inverter.

justed as discussed in Section 3-2.

The frequency is about 40 cps, and can be ad-

This may be desirable if the power line

frequency is a multiple of 40 cps. The maximum open circuit voltage is no more than 20 volts peak to peak. No

more than 80 milliwatts of power can be delivered from this source. 2-8.SPEED OF MEASUREMENT:

Fast measurements are possible by virtue of an

overall 0.25 second response (gO$ full scale) of the output voltage. A zero

switch on the front panel shorts the input to the voltage amplifier, thus

preventing off scale indication while changing samples,. Recovery from over-

load is almost instantaneous and normal operation can be immediately resumed.

2-9.wAF@MJP: has a

15

Operation within the stated specification is-assured if the

minute period of warm-up. It can be used within one minute, but

503

measurements may not be within the accuracy specification.

2-lO.RFCORDING: Output terminals are available at the rear of the instrument.

The output is t100 millivolts across approximately 800 ohms. The output noise

level, above 10 cps, is less than 1miUivolt rms. This output is suitable for driving digital voltmeters and servo-rebalance recorders. The accuracy of the output is

2-11.KWER REQUIRBWWI!: The Model

frequencies from

105

to

125

0.5%

50

v0l-h or

of full scale.

503

can be powered over a range of line

cps to 1000 cps. The line voltages can range from either

210

to

250

v0lts.

No special connections or modifications

are required to operate over the range of power line frequencies.

A three prong power line cord is provided, this is to assure proper grounding

of the instrument to the power line.

2-12.CAXNET OR RACK l.KXlNTING:

The Model

503

is shipped a8 a bench instrument

unless the order call.6 for rack-sreanting. The Model Koch Rack bunting Kit adapts the instrument for standard lg-inch rack mounting. Refer to pragraph 2-18 for conversion instructions.

02

3

OPERATION

MODEL 503

2-13.DESCFUFTION

1. RANGE SELEC!lXX ing from 1 milX.ohm to 300 milJiohms, and seven ohm positions ranging from lob to lOo0 ohms. ibration. (Fig. 3)

2. ON:

indicated by the il&minated front panel pilot Lamp. (Fig. 3)

OPERATE-ZERO: This is a lever switch. 1 With the switch in the up

3. operate) position the 503 is reaw to take measurements. In the down

zero) position the 503 is in zero check.

4.

CALIBMTE:

put voltage of the 503.

justed with a screw driver. (Fig. 3)

VOLTAGE TERMINAL%

5.

the voltmeter circuit.

can be plugged into this receptacle.

6.

CURRENT TERMINAIS:

the current source.

(Fig. 3)

OF CONTROIS AND TERMINALS:

The RANGE SELECTOR has six milliohm positions rang-

A CAL position is provided for Instrument cal-

Toggle switch is the main power switch. Presence of power is

(Fie. 3)

This control is used to calibrate the meter and the out-

It is a recessed slotted control that can be ad-

A 3-pin male receptacle is used for connection to

Pin No. 3 is at chassis ground. Either test lead

(Fig.

3)

A 3-pin male receptacle is used for connection,to

Either test lead can be plugged into this

receptacle.

7. sis.

OUTHJT:

This provides the output voltage for recording. Pin No. 2 is at ckas-

A two terminal receptacle is located at the rear of the chas-

sis ground.

a.

RESET (503C ONLY): This unlocks the contact circuit. A g-pin recep-

tacle at the rear

of

the chassis provides connections for operation with

the contact meter.

OUTHJTCti

9. on the chassis behind the front panel.

This is a slotted control located inside the instrument

This adjusts the value of the out-

put voltage for a full scale reading.

10.

11.

MILIJOHMS CALz This is a slotted control located inside the instru-

ment on the chassis behind the front panel.

ibrated using this control.

use.

This is a factory adjusted control and should not require attention.

KJSE:

A fuse extractor post is located on the rear of the instrument.

A low resistance standard is required for its

The milliohm ranges are cal-

For 117 volt operation use a 3 AG, $ amp fuse; for 234~volts use a 3 AG, * amp.

12.

POWER CORD:

The three-wire cord with ,the NEMA approved three-prong

plug provides a ground connection for the cabinet. An adapter to allow

operation

from

two prong outlets is provided.

0273

MODEL 503

,OPERATION

0273

FIm 3.

140del 503 Controls.

5

OPERATION

2-14.0UTLINE OF PFOCELJJRE:

MODEL 503

1. Connect power cord to power source. nished with the

503.

Power line voltage and frequency range are specified

A three-wire power cord is fur-

on the rear of the instrument.

2. Set ZERO-OPERATE lever to the ZERO position. Set RANGE SELECTOR to lOOC-ohm position.

Turn on the power.

3,

4.

CONNECTIONS: Each test lead set has two clips, one with a red insu-

lator and the other with a black insulator.

Allow 15 minute warm-up.

When making connections use

both test leads, making sure clips with like color insulators are on the

same side of the sample, (Refer to Figure 2) This is necessary to avoid meter readings below zero.

Four terminal connections:

a.

The current leads should be attached

to the sample making sure the test current flows through the entire

sample.

This may include leads on the sample. Attach the voltage leads being sure they are connected only across that portion of the sample to be measured. If the terminals or the leads of the sample

are included in the voltmeter circuit, their resistance will be

included in the reading. (See Section 2-18)

b. Two terminal connections: This type connection is made by attaching together voltage and current clips having like color

insulators and measuring across the sample. (Fig, 4) This type

connection is permissible when measuring samples above 3 ohms.

(See Section 2-18)

5.

OPERATION: With the sample connected, set the ZERO-OPERATE switch to OPERATE, rotate the RAWGE SELECTOR until a deflection is observed. if the RANGE SELECTOR is set at 100 milliohms and a reading of

6.3

is taken, the value of sample resistance IS

63

milliohms.

If the sample is attention should grounding of the

part of a system, be given to the

sample. The voltage lead with the black insulator is the E;;; l..d of the

503.

(See Sec-

I

6. FtEMNING ‘I!m s&m&

Place the OPERATE-ZERO switch in ZERO position

and remove the sample.

2-15.CALIBRATION:

ZERO switch to OPERATE position.

deflection to

Place the selector switch in CAL position. Set the OPERATE-

Turn the slotted CALIBRATE control for needle

7.50

on the meter. The inst-nt can be calibrated independent-

ly of the test leads connected. (See Section

Leads

?

FIGURE

connection.

4-2.)

Sample

4.

Two-terminal

Leads

6

0273

MODEL 503

OPERATION

Z-16. OUTPUT. at ground. RRATE control on the front panel calibrates the output as well as the meter.

An internal contml R125 OUTPUT CAL is adjusted at the factory to insure track-

ing between the meter and the output voltage. If it is desired to use a recorder other than 100 millivolts, the output ter-

minals may be shunted with the following values:

After the divider is added to the output, recalibrate the instrument on the CAL position. CAL control.

2-lT.MEAsuREMENT OF GROUNDED SAMPLES:

be independently grounded at some point. Since the voltage test lead with the black clip insulator is at chassis ground, errors could arise in measurement.

1. using a two-prong power cord adaptor to remove the ground connection to the power line. Place the instrument so that the cabinet is not touching ground. proper insulation.

The 503 is designed to drive a 100 millivolt recorder. The CALI-

Recorder Sensitivity

TEMPORARY MEAsuRe

Connect to the output terminals, observing that pin No. 2 is

(See Figure 14)

Resistance Value

50 m-l

10 mv

lmv

Adjust recorder sensitivity with R125, the internal recorder

FOR OCCASIONALMEASUREMENTS:

If the tilt bail is not used, the rubber feet can provide the

'Z"E 3&Gns

(tap output 7 ohms from ground)

It is possible that the test sample may

Isolate the Model 503

PgRMANENTSET-up:

2. (such as in rack use) the followlng modification will facilitate such measurement. milliohm ranges; the ohm ranges are inoperative.

Remove the chassis ground connection from pin 4 of T-l and pin 3 of J-1. Then connect pin 3 of J-1 to pin 4 of T-l. and current test Leads will be isolated from ground.

J-l

The change allows the instrument to operate only on the

FIGlJF?E 5. Modification for unground chassis.

Should it be necessary to unground the chassis,

In this way both the voltage

(Fig. 5)

c

0273

7

OPERATION

2-18.ACCUBACY CONSIDERATIONS:

MCDEL 503

1. MEASUFiEkKNT IN THE PRESENCE OF Ix: CUBBEETS: sistance with dc currents present in the sample. Aninfluencing factor is the amount of current that will saturate the voltmeter input transformer. A 1% error in measurements, using milliohm range settings, will occur if the dc current causes a 20 millivolt drop across the sample. The dc current through the sample can be increased if a capacitor is put in series with a voltmeter lead. The capacitor should be 10,000 ufd with a voltage rat-

ing greater than the dc current source voltage.

With measurements in the range from 1 ohm to 1000 ohms, a 1% error will

~cur if a current greater than 1 milliampere flows through the current supply circuit. age of the dc current exceeds 50 volts.

The dc sample current which will cause 1 ma to flow in the current supply circuit may be computed from the sample resistance and the range resistor in use.

2. INDUCTIVE ANDCAPACITIVE EFFECTS: system and synchronous demodulation to discriminate against 60 cycle pickup and to discriminate to a degree against reactive components in the sample. Therefore, usually, no special precautions or shielding are necessary unless the ac fields in the neighborhood of the sample are unusually strong. The usual cause of trouble will be due to electro-magnetic induction. Electro-

static pick-up usually is no problem at the impedance involved. A good way to test for pick-up is to remove the current leads and leave the voltage leads attached to the ssmple. If no reading is seen, there is no cause of concern. If, however, there is a reading, the source of magnetic field must be removed or the sample oriented in such a way as to minimize the reading.

The voltmeter will not be effected unless the source volt-

The Model 503 uses an ac measuring

The 503 can measure re-

Because of the ac technique employed, inductive and capacitative components

in the test impedance may cause some wave-form distortion and erroneous readings. In practice, it has been found that the following method will enable the user to calculate errors introduced by inductance in series with the sample or capacitance across it. ExperimentalJy it cm be shown that the error due to a series inductance or shunting capacitance is equal to about 50% of what would be calculated, assuming the shunting or series effect was due to the impedance computed for a 40 cps sine wave.

In the presence of large interfering ac fields, some needle flutter will be noted. This will be due to a beat between the 40 cps carrier frequency and the signal. The average value of the pointer indication will be the correct reading unless the interfering signal is exactly equal in frequency to the carrier. In this case large errors may be encountered. However,. since a 40 cps interfering signal is rarely encountered, there will be little

likelihood of trouble. Coupling between the current and voltage leads can cause significant error

on the 1 milliohm rage. This can be minimized by keeping the voltage and

current leads separated and by twisting the pairs of leads to reduce the

enclosed area.

8

0273

MODEL 503

3.

resistance may be appreciable in such cases as resistivity profile measure-

ments, or when low resistance connections to the sample cannot be made.

(See Fig.

OPERATION

ERRORS IUE M SEFIIES RESISTANCE IN CUkWEN!T AND VOLTAGE LEADS: Series

6)

Current Leads

FIGURE 6. Series Resistance Measurements

The tabulated values will give no more thau 1% errc

2

Ohm range settings

33x

full scale range setting

: in metsurement:

T0tsr.l. resistance

in voL~.age leads 2rv

1 ohm

1oK ohms

=l

0273

9

OPERATION

2-lV.PREPARATION FOR RACK MOUNTIEG. (See Figure 7.)

MODEL 503

1. The Model

bail.

The Model 4CCC Rack Mounting Kit converts the instrument to rack

503

is shipped for bench use with four feet and a tilt-

mounting to the standard EIA (RETMA) 1%Inch width.

Item

(See Figure 7.)

1

2

Description

Cover Assembly Cover Assembly, Bottom (Supplied 1kggOB 1

with Model

503)

Keithley

Part No. Quantity

M23~

1

Angle, Rack llc624B

z

5

TABLW4.

2. To convert the Model

Screw, Phillips Head, lo-32 UEC-

2x4 (Supplied with Model

503)

Front Panel (Supplied with Model

503)

--

Parts List for Model 4000 Rack Mounting Kit.

503,

remove the four Phillips head screws at

i 1

the bottom of each side of the instrument case. Lift off the top cover assembly with the handles; save the four screws. To remove the feet and tilt bail from the bottom cover assembly, turn the two screws near the back. The two pawl-type fasteners will release the cover and allow.it to drop off. Remove the feet and the tilt bail and replace the cover (2).

Attach the pairof rack angles

3.

Phillips head screws (4) previously removed.

(3)

to the cabinet with the four

Insert the top cover assembly (1) in place and fasten to the chassis with.the two pawl-type fasteners at the rear.

Store the top cover with handles, feet and~tilt-bail for

future use.

10

0273

MODEL 503

OPFJUl'ION

/o SCREW

2 COVER ASSEMBLY

L

/ “\

/@COVER ASSEMBLY

FIWJFiE 7. Exploded View for Rack Mounting.

0273

11

CIRCUIT DESCRIPTION

SECTION 3. CIRCUIT DESCRIPTION

The Model 503 circuit consista of four basic sections; a twelve volt auper-

regulated power supply, a trenaiator dc to ac inverter circuit, e four atege high gain vecuum tube amplifier and e silicon diode demodulator.

The twelve volt power supply operates from the line voltage and furnishes a very closely regulated 12 volts. This voltage is used to light the tube filaments and to operate the transistor converter. The converter operates at &C

cpa. operates the demodulator diodes, plus supply for the ac amplifier via e rectifier-filter system.

The vacumn tube aqlifier operates following an input trensfor?ner on the milli-

ohm ranges and directly emplifiea the signel on the ohm ranges. A high degree of gain stability is assured by a substantial feed-back factor and by the use of cloiely reguleted pLate and filaxnent supplies.

The output obtained from the converter transformer via various windings,

YODEL 503

supplies the 40 cps test current end the B-

The output of the amplifier is synchronously demodulated by a silicon diode bridge end the resulting dc signal operates the output circuit and the meter.

D20l R 201

Ill& -

i 1

I I-

IIE

m

I/vL

1

+ c201

T t

1

D202

.

c-IO.5 v

TO Q4

COLLECTOR

- .

0203

12

Figure

8.

Power Supply Schematic Diagram

0273

MODEL 503

CIRCUIT DESCRIPTION

3-1.

mwFa SUPPLY:

(Fig. 8) The power supply consists of three parts:

1. THE AC FOWER TFMSFORMERANDFILTFR-RECTIFIERCIRCUITRY: Thepowertrenaformer, T-2, may be connected for either 117 or 234 volt operation as indi-

cated in the schemetic. at 1 ampere and 117 volts at

The secondaries of the trenafonner supply

5 ma.

The output of the

18

volt winding is full-

wave rectified by DZO3 end D204 end filtered by C202, C2O3 and A202.

clc voltage developed across C2O3 is approximately 20 volts. Neither ter-

minal is grounded since the minus

terminal

of the regnletor is grounded at

the emitter terminal of Ql. The output from the 117 v winding is half-wave rectified by D201 end filtered

by C201. R201 is a dropping resistor for zener diode D202. This diode is

connected between ground and the supply aide of the load resistor for transistor Qk. The purpose of this connection will be discussed below.

2.

THE SUPRR-RFEULATRD I.2 VOLTSUPF'LYz

(Fig. 9) The unregulated 20 volts dc obtained from rectifiers and the transformer is applied to a solid state regnletor consisting of QJ. through

Q6

and D202, D2O5, end ~206. Q5 and Q6 form e differential amplifier which compares the voltage across the output of the regnletor (C2O5 is &cross the output) via divider R210 end R2Og to the voltage supplied by sener reference diode D2O5. If the voltages at the

bases of Q5 and

change is further amplified by Q4, Q3 and Q2.

Q6

are not equal, the collector voltage of Q5 changes. This

The signal is finally applied

to the base of the series element in the regulator Ql. The aignel is always

of such megnitude and phase that output voltege is instantaneously brought

beclr to 12 volts. RF-14 is a forward biased diode which sets the emitter voltage of Qk.

The collector load resistor of Q4, R2O5, is returned to minus

10 volts supplied by sener, D202. This extra reguleted voltage permits Q4

18

volts The

0273

ov>

+>

-10.5>

1

R 206 207

1

C 205

3

R203

E

R205

R204

R206 R209

Figure 9. Super Regulated 12 Volt Supply Schematic Diagram

t12v

13

CIRCUIT. DESCRIPTION

to operate at much higher gain than if the collector load were returned to the unregulated side of the supply and permits linear operation of

Q4 with widely varying input voltages. tant contribution to the performence of the power supply. Q3 and ~$2 are cascaded emitter followers whose function is to increase the current gain

of the series transistor, Ql. provide stability at high temperatures since they make available a backbias current equal to the leakage current of the series transistors at a

temperature of approxSmately &OC.

tion of the power supply. The twelve volts at the output of the regula-

tor powers the filaments of Vl and V2 and the pilot Lamp E-1.

3. 40 CPS TRANSISMR STATIC INVERTER CIRCUIT: (Fig. 10) A portion of the regulated I2 volt power is also used as the supply for a dc converter consisting of the following parts: Q8, diodes IX?07 and D208, capacitors

Pi212 and R213. The operation is as follows: Transistors Q7 and Q8 are

connected across the 12 volt supply through their emitters and the centertap of the 12 volt winding of T3. from another winding on T3.

driven hard on while the other is cut off. core of T3 reaches saturation. keep the on transistor fully conducting and its collector current decrea-

ses.

This causes the polarity of the feed-back winding to change and the

transistor which was cut off now conducts and the conducting transistor is

cut off. The frequency of oscillation is controlled by the transformer

constants. In this case the frequency was picked to be 40 cps. The ten volts rms secondary winding is used to provide the test signal and provides a 20 volt peak-to-peak square-wave which is used with series re-

sistors RI28 through Rl39 to provide the proper test current for each

range. Diodes DlOl and D102 limit the output voltage when the current

leads are open circuited.

This connection makes an impor-

R203 and R204 are added to the circuit to

C204 prevents high frequency oscilla-

Transformer T3, transistors Q7 and

~206

and C207, and resistors R2ll,

The bases receive positive feed-back

The phasing is such that one transistor is

This cycle lasts until the

At this point the transformer can no longer

MODEL 503

TEST CURRENT

SVJITCH

R213 +260

>

I _

I

7

Y

Figure 10. Test Current ,Generator Schematic Dlegrsm

14 0273

MODEL 503

CIRCUIT DESCRIPTION

The 270

fier.

b'and Since the stability of the converter circuit depends only on the

volt Winding pmVideS a B+

of 260 volts for the vacuum tube ampli-

The signal is rectified by D207 and

R213.

~208

and filtered by C207 a and

stability

of the twelve volt power supply, very close regulation is obtained for all

potentials used in the circuit.

100 to

3-2.mT

130

volts have no effect on the instrument.

cm G-R:

(Fig. 10) As mentioned above, the test current is

derived from the 10 volt winding of T-3.

Consequently line voltage variations from

Since Q7 and. Q8 bottom on each half

cycle, the amplitude stability of the signal &pen& only on the 12 volt supply,

and is therefore as stable as the well-regulated I2 volt supply. The circuit

is not particularly critical as to frequency or wave-form. However, e nearly

Perfect square-wave is generated and the frequency is stable to better then a few percent.

The current signal is varied to provide the change in range except between

300 milliohms and 1 ohm where the input transformer is removed from the circuit .

The variation is accomplished by switching resistors

with each current range.

Rlti through ~142 are used in conjunction with RI28

~128

through R139

to keep a constant load on the current source winding to insure a high order of accuracy.

rent leads to plus or minus

Diodes DlOl and DlO2 limit the open-circuit voltage in the cur-

0.5

volts.

3-3.!ciaAc VACDUM-mvom:

put signal passes through transformer T-l.

(Fig. 11) On the Milliohm Renges the in-

This transformer has approximately a 70:1 step-up ratio and improves the impedance match between the voltage signal and the input grid by a factor of

5ooO:l.

On the ohm ranges, where a

Larger signal is obtainable, the transformer is switched out so that its in-

put impedance will not shunt the resistance being measured. Accordingly, on

the Milliobm ranges, the input resistance is about 200 ohms.

On

the Ohms

ranges, the input resistance is one megohm.

The input signal is fed into qhe input of the amplifier either through Tl or around it, depending on range, through Sl, the OPERATE-ZERO switch. This switch

is of the make-before-break variety to prevent switching transients. Following the switch is C102, the input blocking capacitor and Rl.01, the input resistor of the feed-back netwdrk.

R102 connects the feed-back signal to the input grid so that the input grid signal is the difference between the input signal and the feed-back signal or, as it is usually termed, the error signal.

The error signal is amplified by a standard three stage ac amplifier consist-

ing of Vl and.V2a.

V2b is an output cathode-follower which drives the feed-

back loop, Rll8, R143, RI& and RU5; and the meter and output circuits. The gain of the smplifier is varied slightly to compensate for the absence or

presence of the input transformer by shunting RU.4'and Rl45 across R143 in the Milliohm position. milliolnu ranges.

The divided output of Rl18 and R143 through R145 is applied

to RlG2 and returned to the input, completing the feed-back loop.

The MILLIOHM TRIM control is used to calibrate the

A feed-

back factor of 40 db assures high gain stability. The fact that all potentials used in the smplifier are closely regulated, also helps assure a high degree of gain stability and complete freedom from line bounce.

0273

15

CIRCUIT DESCRIPTION

tu >

% 2

MODEL 503

16

5

ml

91

“T

FQur&ll. AC Amplifier Schematic Diagram

g

0273

MODEL 503

The amplifier is stabilized against low frequency oscillation by two sets phase-advance interstage couplings, ~106, C105, R106 and R107 between the two halves of Vl and by CllO, Clog, R1l.l and Rll2 between Vlb and V2a. network introduces an appropriate attenuation and phase lead to prevent os-

cillation and give adequate phase margin. C104, R105; ~108; and Cl13 and

Rll6; are individual high-frequency oscillation stoppers.

CIRCUIT DESCRIPTION

Each

3-4.!lXE SYNCHXONOUS

V2b is coupled through Cll5 and Rllg to a demodulator bridge circuit con-

sisting of D103 through DlO6. The bridge is driven through Rlk6 and R147 from the collectors of Q7 and Q8. Since the center tap of the collector winding is at ground, the drive signal is balanced to ground. When the junction of D103 and DlO5 is positive with respect to the junction of DlO4 and D106, the diodes are conducting and the junction between Rllg and RI20 is effectively grounded.

When the polarity is reversed, the bridge is open circuited. Therefore, the

signal is rectified in this manner. and then is split. the output. panel. this potentiometer is used to correct the meter reading if necessary. RI25 allows calibration of the recorder terminal.

On the CAL position of the range switch, RI27 is switched in and

RI21 is the calibration control.

DEMXLWICR, METERANDOlJTPDT: (Fig. 12) The output of

The output travels through ~120, ~l21

Part of the current drives the meter and the remainder

It is located on the front

RI22

RI24

>-

0273

R

T

A

TRANSISTOR

COLLECTOR

ae

Dl06

DIOS .L

ZERO

BAL

Figure 12.

R

M

G I

I T- I

A

TRANSISTOR

COLLECTOR

at

Synchronous Demodulator Meter - Output

1

O-I MA

Rl2f

17

SERVICING

MODEL 503

SECTION 4.

The Model 503 should not require periodic maintenance. Occasional

verification of the calibration (either section 2-14 or 4-2) and the dc balance (zero balance) should reveal any need for adjustment. If difficulty is encountered, read completely the following material:

4-1. Trouble Shooting Guide

Servicing is quite straight forward as the 503 employs only two vacuum tubes and eight transistors, operated within their ratings. components are used.

The usual caution should be observed when soldering to the printed circuit board as excessive heat will damage the board,

In servicing, bear in mind all operating voltages are obtained from

the 12 volt transistor regulator, either directly or through the

transistor inverter. Reference should be made to Circuit Schematic DR 146280 for voltage

values and other circuit parameters.

SERVICING

all of which are conservatively

No matched or critically selected

In case of complete failure to operate, the fuse, line cord and power source should all be checked.

factory, use the following detailed service procedure to isolate

the trouble:

POWER SUPPLY:

1. THE AC POWER TRANSFORMER AND FILTER RECTIFIER CIRCUITRY

a.

(Figure 8): tion with ZERO OPERATE switch in ZERO position. transistor Q-l from the circuit and measure the voltage

across C203. VTVM) . If approximately 25 volts dc is indicated, this portion of the circuit is in proper working order. Note that neither terminal of C203 is grounded.

Measure voltage across D202, which should be between -9

to -12 volts with respect to ground. If not, check

diodes D201 and D202.

b. THE SUPER REGULATED 12 VOLT SUPPLY (See Figure 9): Re-

place transistor Q-l in the circuit. Determine that the

regulated 12 volts across C205 does not vary more than 5

mv with line voltages from 105 volts to 125 volts.

a variable autotransformer to supply the line voltage.

(General Radio Variac).

Set the RANGE SWITCH to the 3 milliohm posi-

(See schematic notes for recommended type

If these are all found satis-

Remove

Use

18

If no voltage is present or the 12 volts are not regulated, check components in this portion of the circuit.

0577

MODEL 503

2.

40 CFS TRANSISTOR INVRRTER (Figure 10): .With the range switch

set at 3 milliohms, connect the current test leads to an oscillo-

scope. of about 20 volts. If thisis present, across C2Op.

Observe a 40 cps square wave with a peak to peak amplitude

measdre

+260

volts dc

If no square wave is observed, or the B+ is absent,

check the components in this portion of the circuit.

SWVICING

NOTE:

FOR SECTIONS

3

AND

4

THE RANCE SWITCH SHOULD BE IN CAL POSITION

WITH THE Z,li'RO-OmD SWITCH IN THE OPERATE POSITION.

THE AC VACUCM TUBE VOLIKZTER. (Figure 11): Be sure both vacuum

3.

tube filaments are heated and the pilot lsmp is lit. Since the pilot lamp is in parallel with the filament of Vl and the combination is in series with the filament of V2 across the I2 volt

regulator, some service information is provided by its brilliance.

If it lights normally, .it may be assumed the supply is working properly.

out.

pilot itself is open.

If it is brighter than normal, Vl is probably burned

If the lamp is not lit, either V2 is burned out, or the

The instrument will operate without the pilot lamp, but since the life of Vl will be reduced, it should be replaced.

If it is determined the tubes are operating proper& proceed as follows:

peak to peak square wave.

Measure at the iunction of Cl02 and RlOl a 4 millivolt

This indicates the test current is properly reaching the amplifier through the range switch. Should there be no signal, or one of improper magnitude. inspect the range

switch for faulty operati,>n or component failure.

Next, check the voli;age between pin 8 ,:f V2 and ground. This

should be a square wave voltage of abcu~t 10 volts peak to peak. A distortion in/or absence o; this signal indicates a faulty AC amplifier.

0273

4.

SYNCHRONOUS DRMCIXJLA~R - METER OllTKlT (Figure 12): Connect an oscilloscope to the ,Junction of !i.-119 and RI.20 and compare this

wave forn,with Figure 13.

Figure

13

A distortion or absence of this wave form Is an indication of a

faulty demodulator.

19

SERVICING

4-3.

CALIBRATION:

1000 range. is properly calibrated. If the user

The procedure of Section 2-14.calibrates the 503 on then

Other ranges should be within specification once thisrange

wishes

to further verify the CALIEGWPION, or to calibrate for a given range or point, the following procedures are reconunended:

1. OHM RANGES: A standard resistor of at least 0.05% accuracy is reconrmended. ~T'he standard should be selected to 3/4 of full scale of range in question, or to the value of the measurement to be

made.

The slotted control on the front panel will adjust the

meter needle for proper deflection.

MODEL 503

2. MILLIOHMRWG~: low value standard resistor is required. Leeds & Northrup Type 4221-B, 100 milliohms; Type 4222-B - 10 milliohms: and Type 4223-B, 1 milliohm are all suitable. Using one of these resistors or their equivalent, adjust the "MILLIOHM CAL'" (Figure 14) for the

proper meter reading.

To calibrate the milliohm ranges,. an appropriate

20

0273

MODEL 503

SERVICING

0273

FIalm 14.

Model 503 Internal Component6 Tacations (Top Removed).

21

D102

R137

7

R134

rR133

.31 .R130

\ \

\ b129

\-R127

REPLACEABLE PARTS MODEL 503

5-1.

SECTION 5;

REPLACEABLE PARTS LIST. The Replaceable Parts List describes the com-

REPLACEABLE PARTS

ponents of the Models 503 and 503C Milliohmmeters and 5031 Current and Voltage Leads. The List gives the circuit designation, the part description, a suggested manufacturer, the manufacturer's part number and the Keithley Part Number.

The name and address of the manufacturers listed in the

“$ffg,

Code" column

are contained in Table 6.

5-2.

HOW TO ORDER PARTS.

a. For parts orders,

include the instrument's model and serial number, the

Keithley Part Number, the circuit designation and a description of the part. All structural parts and those parts coded for Keithley manufacture (80164) must be ordered from Keithley Instruments, Inc.

listed in the Replaceable Parts List,

completely describe the part, its

In ordering a part not

function and its location.

Order parts through your nearest Keithley distributor or the Sales

b.

Service Department, Keithley Instruments, Inc.

CbVar CerD Comp

CompV

DCb

EMC ETB

ETT f

ampere Carbon Variable

Ceramic, Disc Composition Composition Variable Deposited Carbon

Electrolytic, metal cased

Electrolytic, tubular

Electrolytic, tantalum

farad

Mfg.

MtF

Mil. No.

MY

R

P P

V

Var

Manufacturer Metal Film Military Type Number Mylar

pica (10-l*) micro (10m6) volt

Variable

24

k

M or meg m

kilo (103)

mega (106) or megohms milli (10-3)

TABLE 5.

Abbreviations and Symbols.

w ww

WWVar

watt Wirewound Wirewound Variable

0273

MODEL 503

REPLACEABLE PARTS

MODELS 503, 503C REPLACEABLE PARTS LIST

(Refer to Schematic Diagram 14628D for circuit designations.)

CAPACITORS

Circuit Desig. Value Rating

Cl01

Cl02

Cl03 Cl04 Cl05

Cl06 Cl07 Cl08 Cl09

Cl10

Cl11 Cl12

Cl13 b114 Cl15

Cl16 Cl17

c201 c202 C203 C204 C205

.Ol vf

0.1 pf 100 pf 220 pf

1 Kf

.005 pf

100 pf

.02 pf

1 {lf

.047 uf

100 pf 20 IJf

.002 vf 270 pf 10 pf

56

jpf

56 pf 20 pf

500 uf 500 I*f

.Ol i.Lf

500 pf

50 v 50 v

15 v 1000 v 200 v

1000 " 15 v 1000 " 200 v 200 v

15 " 250 v 1000 " 500 v 200 "

6v 6v

250 v 50 " 50 v 1000 v 25 v

Mfg. Mfg.

TYPO

MY MY

ETB

CerD MY

CerD 72982

ETB 72699

CerD 72982 MY

MY

ETB

ETB CerD Mica

PMC

ETT

ETB

FNC

EMC 14655 CerD 72982

FM2 14655

Code 84411 601PE

84411 601PE 72699 72982

13050 107-21

.13050

14655

7.2689 TDlOO-15 56289 72982 84171 72354 X10316

05397 K56-J6KS 05397 K56-J6KS

56289

14655

Keithley

Part No.

TDLOO-15

831X5R221K

81125V502P C22-.005M

TDlOO-15 841Z5V203P

107-21

WMF2S47 C66-.047M

TVA1508 8OlZ5V202P DM15-271J

TVA1508 AA0160 AA0160

811Z5V103P

AA0120

Part No. C41-.OlM

C41-O.lM Cll-100M c22-22OP C66-1M

Cll-100M C22-.02M C66-1M

Cll-100M C27-20M C22-.002M C21-270P C69-10M

C70-56M C70-56M

C27-20M C57-500M C57-500M C22-.OlM C58-500M

0576

C206 C207

Circuit Desig.

DlOl Rectifier, lA, 800V Dl02 Rectifier, lA, 800V lN4006

D103

D104

D105 Silicon DlO6 Silicon

D107 Silicon lN645 D201 Rectifier, lA, 800V

D202 ZCSX?r

0.22 pf 40-40-2oKf 450 "

TYPO

Silicon lN645 01295 RF-14 Silicon

50 "

MY ENC

Number

lN4006

lN645 lN645

lN645

lN4006 lN715

84411 601PE 56289

DIODES

TVL3786

Mfg.

Code MOT

MOT 01295

01295 01295 RF-14

01295 MOT

12954 DZ-22

C41-0.22M C33-40/40/20M

Keithley Part No.

RF-38 RF-38

RF-14 RF-14

RF-14

RF-38

25

REPLACEABLE PARTS

MODEL 503

DLOIIES (Cant ’

Circuit Desig.

Type

D203 Silicon

Number

lN1563A 04713 D204 Silicon lN1563A D205 ZellGX

D206 Silicon ~207 Rectifier, lA, 800V

D2Og Rectifier, lA, 800V

lN936 04713

lN645 01295

1~4006

d)

Mfg. C0de

04713

MOT MOT

D209 Silicon lN645 01295

MISCELLANEOUS PARTS

Circuit Desig. Description

DS-1

---

Pilot Light Assembly, Red lens (Mfg.

No. 5100)

Bulb, Miniature bayonet base (Mfg.

No. 47)

Fl (117 v) Fuse, 0.5 amp, (Mfg. No. 312.500)

Fl (234 v)

---

Fuse, 0.25 amp, (Mfg. No. 3120.25) Fuse Holder (Mfg. No. 342012)

Keithley Part No.

RF-19 RF-19

DZ-5

RF-14 RF-38

RF-38 RF-14

Mfg. Code

Keithley Part No.

72765 PL-5R

08804

PL-4

75915 W-6

75915 FU-9

75915 FH-3 Jl 52

---

53

---

54 (c) J5 Cc)

---

Kl (c) Ml (4

$11 (c)

Pl

---

Receptacle, VOLTAGE (Mfg. No. XLR-3-32) Receptacle, CURRENT (Mfg. No. XLR-3-32)

Jacb, Mate of Jl and J2 (Mfg. No.

XLR-3-11C)

Receptacle, Microphone, OUTPUT

(Mfg. NO. 80PC2F)

Plug, Microphone, Mate of 53 (Mfg.

No. 80MC2M)

Receptacle, Output (Mfg. No. 126-221)

Same as 54, but does not have jumper

Plug, Mate of J4 and 55 (Mfg. No.

126-220) Relay, SPDT Meter

Contact Meter

Power Cord Set, 6 feet (Mfg. No.

4638-13)

Cable Clamp (Mfg. No. SK-6~-1)

71468 cs-71 71468 cs-71 71468 CS-72

02660 02660 02660

02660 80164

CS-32 cs-33

CS-81

CS-82 RL-3

80164 ME-39 80164 ME-42

93656

co-5

28520 cc-4

26

(a) Used only on Model 503. (c) Used only on Model 503C.

0576

MODEL 503

REPLACEABLE PARTS

MISCELLANEOUS PARTS (Cont'd)

Circuit Desig. Description

Sl

Switch, SPDT, OPBRATE - ZERO (Mfg. No.

3003DL)

s2

---

--s3

Rotary Switch less components, Range Switch Assembly with components, Range Knob Assembly, Range Switch

Toggle Switch, DPDT, ON (Mfg. No.

20905-FR)

S4 Cc)

s5 Tl T2

T3

Pushbutton Switch (Mfg. No. 202)

Slide Switch Transformer, Input Transformer, Power

Transformer, Inverter

Circuit Desig. Value

Rating

RESISTORS

Type

Mfg. Code

82389 80164

80164 80164

04009 82389

80164

80164 80164 80164

Mfg. Mfg. Code

Part No.

Keithley Part No.

SW- 59 SW-114

14722B 153638

SW-14

SW-35

SW-151 TR-53 TR-59 TR-55

Keithley

Part No.

RlOl R102 R103 R104 Rl05

R106

1Ml 1M l%, l/2 w

470 kQ

4.7 m lO%, l/2 w

12

kl

10 B-2 R107 R108 R109 RllO

Rlll R112 R113

Z?, 470 kG

15 ul

10 m

1f-G

470 n R114 100 k0 R115

R116 R117 R118 R119 R120

390 IG 10 lul

10 ko 1m lksl l%, l/2 w

1.8 IQ

l%, l/2 w l%, l/2 w lO%, l/2 w lO%, l/2 w

lO%, l/2 w lO%, l/2 " l%, l/2 w lO%, l/2 w

lO%, l/2 w lO%, l/2 w lO%, l/2 w lO%, l/2 " lO%, l/2 w

lO%, l/2 " lO%, 2 w l%, l/2 w

l%, l/2 w

(c) Used only on Model 503C.

MtF MtF

DCb camp camp

camp camp Comp DCb camp

camp camp camp camp

camp camp

ComP MtF

ww ww

07716

CEC 07716 CEC 79727

CFE-15 01121 EB 01121

01121 01121

EB

EB 01121 EB 79727 CFE-15 01121 EB

01121

EB 01121 EB 01121 EB 01121

EB 01121 EB

01121 01121

07716

01686 01686

EB

HB

CEC

E-30

Rll3-1M Rll3-1M

RlZ-470K Rl-4.7K Rl-12K

Rl-1OM Rl-1M Rl-4.7K RlZ-470K Rl-15K

Rl-1OM Rl-1M Rl-470 Rl-100K Rl-390K

Rl-1OK R3-10K

Rll3-1M

R58-1K R58-1.8K

0273

27

REPLACEABLE PARTS

MODEL 503

RESISTORS (Cont'd)

Circuit Desig. Value Rating

R121 R122 R123 R124 R125'

R126 R127 R128 R129 R130

R131 R132 R133 R134 R135

R136

R137

R138

R139 R140

1kO

2.5 kn 500 R

2.5 k.0 200 $2

700 n 750 n

100.5 0.

301.5 R

1 wl 3k.Q

10 wl

30 ksl

3.33 kfl

33.3 ko 100 IQ.

333.3 ko 1M-l

3.33 Ml 50 n

lO%, 3 w l%, l/2 w l%, l/2 w l%, 112 w lO%, 5 w

l%, l/2 w

O.l%, l/2 w

lO%, lO%, l/2 w

O.l%, O.l%, l/2 w

O.l%, l/2 w O.l%, l/4 w O.l%, 112 w O.l%, l/4 w

O.l%, l/4 w O.l%, l/4 w O.l%, 1 "

O.l%, 1 w

l%, l/2 w

l/2

112

TYPO

WWVar ww ww ww

WWVar 71450

ww

w

ww ww

ww

w

ww ww DALE ww ww ww 15909

ww DALE ww

ww MtF 07716 ww 01686

Mfg. Mfg. Code

Part No.

37942 - RlOOOL 01686 01686 01686

E-30

E-30 E-30 R58-2.5K AW

01686

15909

E-30

1252 R70-750

01686

15909 15909

1252 R70-1K

1252 R70-3K

MFF-1OK 15909 15909

1195 R56-30K 1252 R70-3.33K 1195 R56-33.3K

MFF-100K R-169-1OOK

DALE

MFF-333.3 R-169-333.3K MFF-lM

MEFT-8 R59-3.33M

E-30

Keithley Part No.

RP3A-1K R58-2.5K R58-500

RP3A-200 R58-700

R72-100.5 R72-301.5

R-169-10K

R-169-1M

R58-50

R141 R142 R143 R144 R145

R146 R147 R148

R201

R202 R203 R204 R205

R206 R207 R208 R209 R210

R211 R212

11.1 Q

3.33 R 500 0.

235 R 100 R

lko. 1 kn 100 Q

27 k~

1.5 R 10 kn

680 n 10 kl

300 cl

3.9 k+o

3.9 kn 900 n

a300 R

100 n

1.5 m

l%, l/2 w l%, l/2 w l%, l/2 w l%, l/2 w

D

lo/., 5 w lO%, l/2 w

lO%, l/2 w 30%, l/2 w

lO%, 1 " 5%, 10 w lO%, l/2 w lO%, l/2 w lO%, l/2 w

l%, 112 w lO%, l/2 w lO%, l/2 w l%, 112 w l%, 112 w

lO%, l/2 w lO%, l/2 w

DCb DCb ww ww WWVar

camp camp

compv

camp

ww

79727 79727 01686 01686

71450

01121 01121

71450

01121

94310 01121 01121

camp

ww

COrnP

01121

01686

01121

01686

camp

01121

camp 01121

CFE-15

R12-11.1

R12-3.33 E-30 R58-500 E-30

AW

EB EB

R58-235

RP3A-100

Rl-1K

45 RPlZ-100

GB RZ-27K FR-10 R5-1.5 EB EB EB

Rl-1OK Rl-680 Rl-1OK

E-30 R58-300

EB EB E-30 E-30

EB

Rl-3.9K Rl-3.9K R58-900 R58-300

Rl-100

EB Rl-1.5K

28

* Nominal value, factory

set.

0576

MODEL 503

REPLACEABLE PARTS

RESISTORS (Cont'd)

Circuit Desig.

R213 3.3 ko R214 R215

R216

Circuit Desiec.

9": Q5

Q6 9":

Value

1n

2.2 kJl 1n

Rating lO%, 1 w

l%, l/2 w lO%, l/2 "

l%, l/2 w

Mfr.

Desig.

2N1535

40319

2N1381 2~1381 2N1381

2N1381 2N5193

2N5193

Mfr.

5Ps Comp 01121 GB-332-10% R2-3.3K

DCb Comp

DCb

TRANSISTORS

Mfr.

Code

04713 TG-7 02735 TG-50 01295 01295 TG-8 01295

01295

04713 04713

VACUUM TUBES

Code Desig.

79727 CFE-15-W R12-1

01121 EB-222-10% R1-2.2K

79727 CFE-15-lR RlZ-1

Mfr.

Keithley Part No.

TG-8 TG-8 TG-8

TG-107 TG-107

Keithley Part No.

Circuit Desig.

Vl

v2

Description

Test Two Alligator Clips (Mfg. Series 60)

Jack (Mfg. No. XLR-3-11C) 71468

lead, 48 inches

Mfr.

Desig.

7025

6U8 81453 KV-6U8A

MODEL 5031 REPLACEABLE PARTS LIST

Mfr.

Code 73445 EV- 7025

Keithley Part No.

Mfr.

Code 80164

76545

Keithley Part No.

14731B

AC-1

CS-72

0874

29

01121

Allen-Bradley Corp. Milwaukee, Wis.

02660

Amphenol-Borg Electronics Corp. Broadview Chicago, Illinois

01295

01686

04713

05397

07716

08804

12954

13050

14655

15909

28520

37942

56289

71450

7146%

72354

72699

Texas Instruments, Inc. Semi-Conductor-Components Division

Dallas, Texas RCL Electronics, Inc.

Riverside, N. J.

Motorola, Inc.

Semiconductor Products Division Phoenix, Arizona

Kemet Co.

Cleveland, Ohio International Resistance Co.

Burlington, Iowa Lamp Metals and Components

Department G. E. Co.

Cleveland, Ohio

Dixon Electronics Corp.

Scottsdale, Arizona

Potter Co.

Wesson, Miss.

Cornell-Dubilier Electric Corp.

Newark, N. J. Daven Co.

Livingston, N. J. Heyman Mfg. Co.

Kenilworth, N. J.

Mallory, P. R., and Co., Inc.

Indianapolis, Ind.

Sprague Electric Co.

North Adams, Mass.

CTS Corp.

Elkhart, Ind. Cannon Electric Co.

Los Angeles, Calif.

Fast John E. and Co.

Chicago, Ill.

General Instrument Corp. Newark, N. J.

02735

04009

72982

73445

75042

75915

76545

79727

80164

81453

82389

82879

84171

84411

94310

99942

RCA Semiconductor and Materials Division of Radio Corp. of America

Somerville, N. J.

Arrow-Hart and Hegeman Electric Co. Hartford, Corm.

Erie Technological Products, Inc. Erie, Pa.

Amperex Electronic Co. Division of North American Philips Co., Inc. Hicksville. N. Y.

International Resistance Co.

Philadelphia, Pa. Littelfuse, Inc.

Des Plaines, Ill. Mueller Electric Co.

Cleveland, Ohio Continental-Wirt Electronics Corp.

Philadelphia, Pa.

Keithley Instruments,Inc.

Cleveland, Ohio

Raytheon Co. Industrial Components Div. Industrial Tube Operation Newton, Mass.

Switchcraft, Inc. Chicago, Ill.

Royal Electric Corp. Pawtucket, R. I.

Arco Electronics, Inc. Great Neck, N. Y.

Good-All Electric Mfg. Co. Ogallala, Nebr.

Tru Ohm Products Div. of

Model Engineering and Mfg., Inc.

Chicago, Ill. Hoffman Electronics Corp.

Semiconductor Division El Monte, Cal-if.

72765

30

Drake Mfg. Co.

Chicago, Ill.

93656

Electric Cord Co. Caldwell, N. J.

0273

/ II

Tektronix 503 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual