Keithley 169 Service manual

Instruction Manual

Model 169

Digital Multimeter

01979, Keithley Instruments, Inc.

Cleveland, Ohio, U.S.A

Document Number 30161

TABLE OF CONTENTS

SECTION

1.

GENERAL INFORMATION.

1.1.

INTROOUCTION

1.3.

FEATURES .......................... l-1

1-5.

WARRANTY INFDKMATION ....................

l-7.

CHANGE NOTICES

1-9.

SAFETY SYMBOLS

l-11. SPECIFICATIONS

2.

OPERATION.
2-l. INTRODUCTION

2-3.
2-5.
2-6.
2-7.
2-8.

2-10. Front Panel Switches
2-12. Input Connections.
2-14. Tilt Bail/Handle
2-16. INITIAL FUNCTIONAL CHECK
2-18. OPERATING INSTRUCTIONS
2-20. DC VOLTAGE MEASUREMENT
2-22. AC VOLTAGE MEASUKEMENT
2-24. AC OR DC CUKRENT MEASUREMENT
2-26. RESISTANCE (n) MEASUREMENT

3.

PERFORWINCE VERIFICATION

3-1.

3.3.

3-5. ENVIRONMENTAL CONDITIONS .................. 3-l

3-7.

3-9. Initial Conditions
3-11. DC Volts Checkout.
3-12. AC Volts Checkout.

3-13. Resistance Checkout.
3-14. DC Current Checkout.
3-15. ANALYSIS

4.

ACCESSORIES.

4-1.
4-3.
4-5.
4-7.

4-9.

4-11.

4-13. MODEL 1684 CARRYING CASE
4-15. MODEL 1635 CLAMP-ON AC CURRENT PROBE
4-17. MODEL

4-19.

4-21. MODELS

............................ 2-l

UNPACKING AND INSPECTION .................. 2-l

PREPARATION FOR USE. .................... 2-l

Installation of Batteries, if required ........... 2-1

CONTROLS, INDICATORS AND CONNECTORS. ............

Display ........................... 2-1

GENERAL ........................... 3-l

RECOMMENDED TEST EQUIPMENT ................. 3-1

PERFORMANCE VERIFICATION PROCEDURE ............. 3-1

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

GENERAL ........................... 4-l

MODEL

1600

MODEL

1651

MODEL 1681 CLIP-ON TEST LEAD SET .............. 4-l

MODEL 1682 RF PROBE. ....................

MODEL 1683 UNIVERSAL TEST LEAD KIT

1691

MODEL

1699

1010

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.................... 3-3

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HIGH VOLTAGE PROBE. ............... 4-l

50-AMPERE SHUNT ................. 4-1

............. 4-2

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

............ 4-2

GENERAL PURPOSE TEST LEAD SET

SPARE PARTS KIT

and 1017 RACK MOUNTING KITS.

................. 4-2

.......... 4-2

.......... 4-2

PAGE

l-l
1-l

1-2
1-2
l-2
1-2

2-l

2-l

2-2
2-4
2-4
2-4
2-5
2-5
2-5
2-6

3-l

3-2

3-2

3-3
3-3

4-l

4-1

4-2

5.

THEORY OF OPERATION.
5-l.

GENERAL.

5-3.

OVERALL OPERATION.

5-6.

SIGNAL CONDITIONING.

5-7.

AC/DC Voltage Measurements

5-10.

AC/DC Current Measurements

5-12.

Resistance Measurements.

5-14.

A/D CONVERTER.

ii

I

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.......

.......

........

........

........ 5-l

........ 5-l

........

........ 5-I

........ 5-2

........ 5-2

6-l
5-l

5-I

i i

TABLE OF CONTENTS (Cont'd)

SECTION

5-16. DISPLAY CIRCUITS
5-18. REFERENCE SOURCE
5-20. LOW BATTERY DETECTOR
5-22. INPUT PROTECTION
5-24. Voltage Protection
5-27. Current Protection
5-29. Ohms Protection.

6. MAINTENANCE.

GENERAL ...........................

6-1.

CALIBRATION. ........................

6-3.

Recormended Calibration Equipment.

6-5.

Environmental Conditions

6-7.

Case Cover Removal

6-9.
6-11. Calibration Adjustment
6-14. TROURLESHOOTING.
6-16. Special tiandling of Static Sensitive Devices
6-18. Power supply
6-20. A/D Converter and Display Driver
6-22. AC Converter
6-24. Voltage Divider, Reference Source and Ohms Circuit
b-26. Current Circuitry.
6-31. LIQUID CRYSTAL DISPLAY REPLACEMENT
6-33. BATTERY REPLACEMENT.

6.35. CURRENT FUSE REPLACEMENT

7. REPLACEABLE PARTS.

GENERAL ...........................

7-I.

ORDERING INFORMATION

7-3.

FACTORY SERVICE.

J-5.

SCHEMATIC. .........................

7-J.

COMPONENTS LAYOUT.

7-9.

J-11.

MODEL

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

1699

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

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

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

SPARE PARTS KIT

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

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

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.....

PAGE

5-2
5-3
5-3
5-3
5-3
5-3

5-3
6-1
6-l
6-l
h-l
h-l
6-1
6-I
6-2
6-2
6-3
6-3
h-3
6-3
6-3
6-4
6-9
6-9

7-D

7-o
7-D

7-O

7-O
7-D
7-O

FIGURE

l-l

2-l
2-2
2-3

4-l
4-2
4-3
4-4
5-I
5-2
5-3
5-4

6-1

6-2
6-3
6-4
6-5

7-l

ILLUSTRATIONS

TITLE JhGJ

Model lG9.

Installation of Batteries.
Model 169 Front Panel Display.
Operating Controls
High Voltage Probe and RF Probe.
Current Probe and Current Shunt.
Convenience Cable and Connectors
Carrying Case and Hack Mounting Kits
Model 169 DMM Overall Signal Flow Block IDiagram.
Simplified AC/DC Voltage Measurement
Simplified AC/DC Current Measurement
Simplified Resistance Measurement.
Calibration Adjustment Location.
LCD Assembly

Integrator Waveform.
AC/DC Converter Waveform
Current Fuse Removal/Replacement
Covers and Panels.

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

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.... 5-5

I-1
2-o
2-O
2-3

4.2

4.3

4.3

4.4

5-6

5-J

5-8
6-2

6-4

6-6

6-J

6-9

7-4

MOOEL 169

GENERAL INFORMATION

SECTION 1. GENERAL INFORMATION

l-l.

INTRODUCTION.

The Model 169 is a rugged, low cost, battery-

l-2.
operated digital multimeter that provides full
measurement capability for many general purpose
applications.
IOOuVldigit to 1OOOV on five dc and five ac voltage
ranges, lOOnA/digit to 2000mA (2 amperes) on five dc

and five ac current ranges, and lOIlmn/digit to 20
megohms on six resistance ranges. Ranges and
~ccurxy are listed in the Table of Specifications
on page 1-3.

FEATURES.

l-3.

The Model 169 incorporates features that help

l-4.
prevent instrument damage through customer abuse and
provide maximum instrument reliability, operator
safety and simplicity of operation.
features are:

A ZOOO-count (3-l/2 digit) liquid crystal dis-

e

play (LCD) with large 0.6" numerals, function
and range annunicators, and a low battery indi-

It provides dccurate readings from

Some of these

cator (BAT).
minus sign (-) are also displayed, positive
polarity is implied.

l

The Model 169 is built rugged. The full bench­sire cdse is molded from impact-resistant dnd
flame-retardant plastic.

tection prevents damage on all
Voltage ranges dre protected up to 1400V peak,
resistance ranges to 300VRMS and current ranges
dre protected by dn externally accessible 2A

(25OV) fuse.

0 Pushbutton switches dre color coded to the

front panel for quick and edsy selection of

function and range. The decimal point is duto­matically positioned by the rdngc pushbutton.
Annunciators on the display
selected function and range.
and function combinations are indicated by
contradicting function and/or range d""u"cid­tars appearing dt the sdme time.

Appropriate decimal point and

Effective input pro-

functions.

Indicate

Improper range

the

FIGURE l-l. Model

169.
l-l

GENERAL INFORMATION

The latest LSI technology and stable precision

l

components have been used in the Model 169 to

provide long term accuracy and minimize main-

tenance.

required, once a year. If alkaline batteries
are used, battery life can be the same as the
calibration cycle.
an MTRF of up to 20,000 hours can be expected.

Only one calibration adjustment is

Barring destructive misuse,

MODEL

l-l.

CHANGE NOTICES.

l-8.
which occur after printing of the Instruction Manual
will be explained on a Change Notice sheet attached
to the inside back cover.

l-9.

Improvements or changes to the instrument

SAFETY SYMBOLS.

169

Automatic zeroinq, automatic polarity and only

l

two input terminals simplify operation by
eliminating potentiometer zeroing and lead

changing.

Optional accessories can be ordered to extend

l

the measurement capability of your Model

Some of these are:

High Voltage Probe allows your DMM to measure
from 1000V to 40kV dc.

High Frequency (RF) Probe allows your DMM to
measure from 0.25V to 30V rms ac over a fre­quency range of IOOkHZ to IOOMHZ.

Clamp-On AC Current Probe allows your DMM to
measure from zero to 200A rms ac.

50.Ampere Current Shunt allows your IXIM to
neasure from zero to 50A. ac and dc.

NOTE

Refer to Section 4 for more detailed

information on accessories.

l-5.

WARRANTY INFORMATION.

169.

l-10.

follows:

l-11.

1-12.

given in Table I-I.

Safety symbols used in this manual we as

IMPORTANT

The A symbol can be found in various
places in this manual. Carefully read the
associated CAUTION statements with regard
to proper use and handling of the instru­ment. Damage to the instrument may occur
if these precautions are ignored.

This
places in this manual. This svmbal indi­cates those areas on the instrument which
are potential shock hazards. Carefully
read the associated WARNING statements
with regard to proper use and handling of
the instrument. Serious personal injury

result if

w
ignored.

SPECIFICATIONS.

Detailed specifications for the Model 169 are

symbol can be found in various

these precautions are

l-6.
cover of this Instruction Manual.

need to exercise the warranty, contact the Keithley
Representative in your area to determine the proper
action to be taken.
facilities in the United Kingdom and West Germany,
as well as in the United States.

front cover of this manual for addresses.

1-2

The warranty is given on the inside front

If there is a

Keithley maintains service

Check the inside

MODEL 169

GENERAL INFORMATION

TABLE 1-1.

Specifications

Mode

1169

MAXIM”M ALLOWABLE INPUT: 10”“” ims. ,400” prak.

,“*“.Hr. cO”ti”“o”S except 2”“m” range: 35”” m”,i”uuLkr. 15
sec. rndXirnUnl above 35”“.

1-3

BATTERY

ADJUSTMENT
RlO,

l-

FIGURE 2-1.

NEGATIVE
DISPLAYED,

POSITIVE

IWLIED WHEN LW

MINUS l-1 CFF

AC DIPLAYEO,

DC IWLIE"

FIGURE 2-2.

BATTERY

I

3-l/2 DIGITS

WITH DECIMAL

-__

Installation of Batteries.

MILLI (10-3)

MICRO I 10-6)

I

POINT

Model 169 Front Panel Display.

2-O

I

MODEL 169

SECTION 2. OPERATION

OPERATION

2-1. INTRODUCTION,

2-2. This section provides information needed for
incoming inspection, preparation for use and opera­tion of the Model 169 and its accessories.

2-3. UNPACKING AN0 INSPECTION.

2-4. The Model 169 was carefully inspected, both
mechanically and electrically before shipment. Upon
receiving the Model 169, unpack all items from the

shipping container and check for any obvious damage
which (may have occured during transit.
damages to the shipping agent. Retain and use the
original packaging materials if reshipment is re-

quired.
Model 169 orders:

a. Model 169 DMM

b. six carbon zinc "C' cells (may be shipped

installed in the DMM in some units).

c.

d.

2-5.

2-6.

The following items are shipped with all

A copy of this Manual.

Separate optional accessories, as ordered.

PREPARATION FOK USE.

Installation of Batteries, if required.

neport any

NOTE

Carbon-zinc batteries are supplied. These
batteries will operate your DMM for ap­proximately 1000 hours. If it is desired
to change batteries only once a year when
calibration is required, alkaline cells

may be substituted. These cells will pro-

vide approximately 2000 hours of opera-

tion.

indicator will automatically come on with

approximately 5% of battery life remaining

(20 hours for carbon-zinc and 40 hours for

alkaline cells).

t. Install the batteries in the holder ds shown

in Figure 2-1.

d. Press the battery clip onto the terminals of
the battery holder; then position battery holder on
the two spacers as illustrated.

e. Reinstall the top cover.

f. After the batteries are installed. you should
become familiar with the Model I69 by reading the
section titled Controls, Indicators and Connectors
(Paragraph Z-7); then perform the Initial Functional

Check (Paragraph Z-16).

In either case,

the low battery

WARNING

3

To prevent a shock hazard, all test leads

should be removed from the INPUT terminals

before removing the instrument top cover.

a. Turn the DMM bottom side-up and loosen the
four screws in the bottom cover until the threads
are not engaged.

and they will fall out when the instrument is re­turned to its normal position.

b. Hold the top and bottom ‘over together to
prevent their separation and turn the DMM cover to
normal position.

NOTE: The scrws are not retained

Lift off the top cover.

2-7.

CONTROLS, INDICATORS AND CONNECTORS.

2-B.

Display.

2-9. The operating status of the Model 169 is con­tinuously provided by the 3-l/2 digit (2000 count)
liquid crystal display located on the front panel.

In addition to the digitized input signal, with
appropriate decimal point and polarity, the display
provides indications of the selected function and
range, battery condition and overrange. All indica­tors on the display are shown in Figure 2-2 and
described as follows.

2-1

OPERATION

MODEL 169

a. Numerals.

maximum of 1999 counts.

pressed for most significant (l/Z) digit.

b. Decimal Point. The decimal point is indicated
in three positions and implied when behind the least
significant digit. The decimal point is properly
positioned when a range pushbutton is pressed.

C. Overrange. A "1" followed by three blanked
digits is displayed as an overrange indication for
all ranges and functions, except the 1000 volt
ranges which read beyond their maximum allowable
input voltages. The minus sign and a decimal point

may also be displayed, if appropriate.

d. Polarity. For dc measurements the minus sign

(-) is displayed, positive is implied. The minus
sign may flash on any function at zero since it is
not suppressed. It is also normal for it to flash
in ohms while the instrument is recovering from
overrange.

e. Low Battery Indication. BAT is displayed when
approximately 5% of battery life remains.
indicates that the batteries should be replaced,
however the Model 169 will continue to operate pro­perly for 40 hours if alkaline cells are installed,
or 20 hours if carbon-zinc cells are installed.

f. Function and Range Annunciators.

cators provide a continuous display of the selected

funCtiOn and range, and allow direct reading of the

display. For example:
current on the highest current range would read AC

IOOOmA.

Large 0.6" numerals display up to a

Leading zero is only sup-

This

These indi-

a displayed half-scale ac

Z-10. Front Panel Switches.

Z-11.

eleven pushbutton switches which are color coordi­nated to the front panel. These switches are shown
in Figure 2-3 and described as follows.

that, when in, applies power to the DMM.

buttons provide selection of the five functions of
the Model 169.
that selects whether the function is ac or dc, in
for ac or out for dc.
annuncmtor is on.

is implied. The AC/DC pushbutton is not effective
when ohms (0) is selected.
buttons are push-on switches that select volts,

amperes and ohms, respectively.
these pushbuttons all the way in selects the new
function, turns on the proper annunciator and can­cels the previously selected function. Note that it

is possible, by forcing, to push two pushbuttons in
at the same time. This will be evidenced by con­flicting range/function annunciators appearing, and
the unwanted function can be canceled by pressing
the desired function pushbutton again.

are push-on switches which select the new range and
cancel the previous one. The decimal point is posi­tioned and the appropriate annunciator is turned on

when the range is selected. The 20M pushbutton is
only used for ohms function. If it is inadvertently

selected with volts or current, contradicting annun-

ciators will appear.

Control of the Model 169 is provided by

a. ON/OFF Pushbutton. Push on - push off switch

b. Function Pushbuttons. The four function push-

AC/DC is a push on - push off switch

When ac is selected, the AC

When the annunciator is off, dc

The Y, A and " push-

Pressing one of

c.

Range Pushbuttons. The six range pushbuttons

2-2

NOTE

Extended exposure of the liquid crystal
display to direct sunlight, or high tem­perature and high humidity conditions can
cause the display to temporarily blacken.

Also, the display may become sluggish if

exposed to extremely cold temperatures.
Even though recovery occurs at normal
Operating temperatures. these conditions

should be avoided for maximum display
life.

2-12.

Z-13.
tions to the Model
high impedance input and is normally connected to
the point in the test circuit most removed from sig­nal or earth ground.

common or low inout.

Input connections.

Two banana jacks provide the input connec-

169.

The HI (red) jack is the

The LO (black) jack is the

I

MODEL 169

TABLE 2-1

Initial Function Check

OPERATION

STEP FUNCTION RANGE INPUT READING

1

2 ACV 200"V Shorted 00.0 ACmV
3 DC"

4

5

6

SELECTION DMM

200mV Shorted

A and n* 2k

A and n*

A and n* 2DOn and

200n

and Open 1.00.0 ,,An

2mA

open

open .I00 mAkn

Open 1.0.0 uAfl Display reads 20mA current shunt on 200n range.

DISPLAY

000

00.0 "V

2olTd (100)

7 ”

8 n
9 " 20DOk Open

2DM
2DOOk Shorted

Shorted

*Press both pushbuttons simultaneously.

0.00 M"
000 k"

1

kn Overrange indication, leading 1 with all other

REMARKS

Power on, all other switches out. (-1 mdy flash.

Display reads 2mA current shunt on 2kn range.
Checks current fuse.

Display reads 2mA current shunt on 200n range.

(approx. loon)

digits blanked.

SET PWER Q4

@SELECT F"NCTI(N

FIGURE 2-3. operating COntPOlS.

@SELECT

RANGE

@CONNECT

SOJRCE

IEZ302,A

z-3

OPERATION

MODEL 169

Z-18. OPERATING INSTRUCTIONS.

WARNING

t

To avoid electrical shock and/or instru­ment damage, do not connect the LO input
to any source of more than 1400 volts

(peak) above earth ground.

2-14. Tilt Bail/Handle.

2-15. The 16 position tilt bail/handle allows you
to position the instrument for the best viewing
angle of the display.

2-16.

Z-17.

have become familiar with your OMM, the initial
checkout procedure given in Table 2-1 should be per­formed. This procedure provides d quick and easy
functional check of the DMM. Only test leads are

required.
ciators to appear, except for low battery (BAT).
All decimal point locations are checked. All digit
segments are checked, except for the horizontal cen­ter segment on the last three digits.
minus sign (-) is not suppressed on any function, it
should periodically flash on one or snore of the

funcrions at zero with the input shorted. By

selecting two functions and/or ranges in the test,
the current fuse is checked and d rough indication
of the condition of the respective current shunt and

range resistor is obtained.

not intended to check the DMM accuracy, and thus,
the indicated readings in the table are nominal with

*5 digits allowed. If it is desired to check the
DMM accuracy specifications, perform the Performance
Verification, Section 3.
Check is begun with power on and all other push­buttons wt.

necessary to press unselected function and range

pushbuttons slightly to cancel previous selections.
After completing the functional check, operate the
Model 169 in accordance with the Operating Instruc­tions beginning with Paragraph 2-18.

INITIAL FUNCTIONAL CHECK.

Now that the batteries are installed and you

The check is designed to cause all annun-

Since the

However, this test is

The Initial Functional

To obtain this condition it may be

2-19.

Model
there are individual instructions provided in this
section which describe how to nakt specific function
meas"rements.
DMM as follows.

button.
useable immediately to rated accuracy.
ambient temperature is within 18-28°C range, but the
DMM has been subjected to temperature extremes, up
to I hour may be required to obtain rated accuracy.

pushbuttons.

range pushbutton.

the medsupement.
should be used ds required.

The basic operating instructions for the

169

DMM are outlined below. In addition,

Refer to Figure 2-3 and operate the

CAUTION

A

Do not exceed the maximum input limits
given in Table 2-2.

a.

Turn on power by depressing the ON/OFF push-

If the instrument is within I&28“C, it is

If

the

b. Select the function with the AC/DC, V, A or n

c. Select the range by depressing the appropriate

d. Connect the source to the INPUT jacks and make

Accessories described in Section 4

TABLE 2-2

Sumnary of Maximum Inputs

-

MAXIMUM

INPUT

1OOOV DC, 1400V Peak AC

350V rms continuous, 15

sec. maximum above 350V

IOOOV rms, 1400 peak,

lO%.Hz

ZA, 250V DC or rms (fuse

protected)

2-4

I

MODEL 169

OPERATION

Z-20.
Z-21.

digit to 1000 volts.

is 1999 with appropriate decimal point. Polarity is
automatically sensed and the minus sign (-) will be
displayed, if applicable.
a "1" and three blanked digits, except on the 1OOOV
range.

beyond the maximum allowable input voltage. Maximum
allowable input: 1OOOV dc, 1400 peak ac. Use the
Model 169 to measure dc voltage as follows:

select dc volts with the V and AC/DC pushbuttons.

The "V" annunciator should appear.

able.

pushbutton.

2QOmV range is selected.

INPUT HI and LO jacks; observe the voltage reading

on the display.

2-22.

2-23. The Model 169 reads ac voltages from lOOuV/

digit to 1000 volts.

responding, calibrated to read the root mean square
value of a sine wave within a frequency of 45Hz to
5kHz.
decimal point.
lowed by three blanked digits, except on the IOOOV
range.
beyond the maximum allowable input voltage. Maximum
allowable input voltage:
106V.Hz maximum.
ac voltage as follows.

OC VOLTAGE MEASUREMENT.

The Model

On the 1OOOV range, the display can read

00 not exceed the maximum allowable input
voltage. Instrument damage may occur.

Turn on power with the ON/OFF pushbutton;

a.

Select the range from the five ranges avail-

b.

The decimal point is positioned by the range

c. Connect the signal to be measured between the

AC VOLTAGE MEASUREMENT.

The maximum reading is 1999 with appropriate

On the 1OOOV range, the instrument can read

169 reads dc voltage from 1OOpV/

The maximum displayed reading

Overrange is indicated by

CAUTION

A

The 'm' annunciator will appear if

The instrument is average

Overrange is indicated by a "1" fol-

1ooov Pm,

Use the Model

1400V peak,

169 to measure

A

CAUTION

00 not exceed the maximum allowable input

voltage.

Turn on power With the ON/OFF pushbutton;

a.

select dc volts with the V and AC/DC pushbuttons.

Select the range from the five ranges avail-

b.
able.
pushbuttons.
200mV range selected.

INPUT Hi and LO jacks; observe the voltaqe readin
on the display.

2-24.

2-25.

lOOnA/digit to 2000 milliamperes (ZA). For ac mea­surements the instrument is average rsponding, cali­brated to read the root mean square value of d sine
wave of d frequency within 4%~ to
mum reading is 1999. with appropriate decimal point.
Overrange is indicated by d
blanked digits.
vided by ZA, 250V dc or rms, quick-blow fuse.
the Model 169 to measure, ac or dc current as
follows.

The decimal point is positioned by the range

C. Connect the signal to be measured between the

AC OR DC CURRENT HEASUREIIENT.

The Model

00 not install .3 larger capacity current

fuse than the one originally supplied (ZA,

25OV).

Turn on power with the ON/OFF pushbutton.

a.

Select ac or dc with the AC/DC pushbutton; depress A
pushbutton.
with the "AC" annunicator if dc was selected.

instrument damage may occur.

The "rn' annunciator will appear if

169

reads ac and dc currents from

1kHz.

“1”

followed by three

Input overload protection is pro-

CAUTION

A

Instrument damage may occur'.

The "A" annunciator should appear along

The maxi-

Use

2-5

I

OPERATION

Select the range from the five ranges avail-

b.

able.

pushbutton.
200uA range was selected; otherwise, the W annun­ciator will appear.

voltage drop across the current shunt in the instru­ment (called voltage burden) can affect the circuit

under test if it has a low source voltage.

voltage burden can be reduced by selecting the

highest current range that will resolve the desired
meas"rement.

HI and LO jacks; observe the current reading on the

display.

The decimal point is positioned by the range

The '11" annunciator will appear if

It should be noted that the

C. Connect the signal to be measured to the INPUT

2-26.

2-27.
digit to 20 megohms.
with appropriate decimal point.
cated by a
Maximum Allowable Input: 3OOV dc or rms. Use the
Model 169 to measure resistance as follows.

RESISTANCE (n) MEASURENENl

The Model 169 reads resistance from 1OOnW

The maximum reading is 1999

Overrange is indi-

"1" followed by three blanked digits.

CAUTION

A

Turn the test circuit off and discharge

all capacitors before attempting in­circuit measurements.
present in the circuit if either the minus
sign is displayed, along with a steady
displayed number other than zero, OP the

reading changes more than two digits when

the leads are reversed.

A voltage may be

This

MODEL 169

c.

Read the resistance an the display.
ZOOn range is selected, disconnect the test leads at
the test circuit, short them together and subtract
the reading obtained from the reading obtained
above.

NOTE

As previously mentioned far in-circuit
meas"rements, the presence of a voltage
will cause a change in the reading when
the leads are reversed. The presence of a
forward biased semiconductor junction will
also cause a significant error, and there-

fore, it is a good practice to reverse the
leads and make comparative measurements of
in-circuit resistances.
should be noted that the bottom two re­sistance ranges will not turn on most
semiconductors, except in an overrange
condition.

d. Diode Tests. Any of the top four ohms ranges

will turn on semiconductor junctions, with an

on-scale reading. but the 20Kn range is recommended
for out-of-circuit tests of semiconductors because
its test current is higher. To test a junction,
first forward bias it and then reverse bias it while
observing the display reading for both conditions.
The HI jack is positive. Compare the results as
follows:

INDICATION

In addition, it

If the

JUNCTION
CONDITION

Turn on power and depress the 0 pushbutton.

a.

The "n" annunciator should appear.

b. Connect the circuit to be measured to INPUT HI
and LO and select the desired range from the six
ranges available.
by the range pushbutton and the applicable range
annunciator should appear.

2-6

The decimal point is positioned

1. Overrange. both Polarities

2. Low reading, both polarities

3. Overrange when reverse biased
and an on-range reading when
forward biased

OPEN

SHORTEO

PROBABLY
GOOD

MODEL 169

PERFORMANCE VERIFICATION

SECTION 3.

3-l.

GENERAL.

3-2. Performance verification inay be performed upon

receipt of the instrument to ensure that no damage

or misadjustment has occured during transit.

fication may also be performed whenever there is
question of the instrument's accuracy, and following
calibration, if desired.

NOTE 3-5.

For instruments that are still under war­ranty (less than 12 months since date of
shipment), contact your Keithley repre­sentative or the factory immediately if
the instrument falls outside of specifica­tions as determined by the Performance
Verification Procedure in paragraph 3-7.

PERFORMANCE VERIFICATION

Veri-

RECDHMENOEO TEST EQUIPMENT.

3-3.

3-4. Recommended test equipment for perfornance

verification (and calibration) is listed in Table

3-l. Alternate test equipment may be used.

ever, if the accuracy of the alternate test equip-

ment is not at least 10 times better than the

instrument specifications, additional allowance must

bc made in the readings obtained.

ENVIRONMENTAL CONDITIONS.

3-6. All measurements should be made at an ambient
temperature within the range of la0 to 28OC (65" to
BZ'F), and a relative humidity of less than 80%.

3-7.

PERFORWNCE VERIFICATION PROCEDURE.

3-B.
basic accuracy of the Model
resistance and current measurements.

Use the following procedures to verify the

169 for vo:tage,

HOW-

ITEM

-

A

B

C

0

E

TABLE 3-l

Reformended Test Equipment for Performance Verification.

DESCRIPTION

DC Calibrator

SPECIFICATIONS

O.lV, lV, lOV, IOOV

Fluke

1ooov , to .005%

AC Calibrator

AC Calibrator/Amplifier

Decade Resistor

O.l”, 1”. lo”, 1oov

*0.0223

1000" 20.04%

1.9k", 19kn,

190kn,

H-P

H-P

ES1

1.9Hfl, lOMn,

?0.02%

Current Calibrator

lOOpA, lmA, lOmA.

IOOmA, 1A. to.034

Valhalla

IMFR .

MODEL

341A

745A

745R/746A

0862

2500

3-l

PERFORMANCE VERIFICATION

I

MODEL 169

NOTE

Performance verification should be per­formed by qualified personnel using
accurate and reliable test equipment.

3-9. Initial Conditions.

3-10. Before beginning the verification procedure
the instrument must !meet the following conditions:

a. If the instrument has been subjected to
extremes of temperature, allow internal temperature
to stabilize for one (1) hour minimum at the
environmental conditions specified in paragraph 3-5.

b. Turn the instrument on and check for low
battery indication. If low battery indicator (BAT)

is on, remove and replace the batteries with fresh

O”L?S.

t

Some procedures require the use of high

voltage. Take care to prevent contact
with live circuits which could cause
electrical shock resulting in injury or
death.

3-11.

DC Volts Checkout.

WARNING

TABLE 3-2

DC voltage Perfornance Check

Applied

Range

ZOOmV

20 v

200 v

1000 v

3-12.

a. Select ac voltage readings with the AC/DC and

V pushbuttons.

b. Connect the AC Calibrator (Item B, Table 3-1)

to the OMM.

c. Set the DMM to the 200 mV range and apply

mV ac to the OMM. The reading must be within the

limits specified in Table 3-3.

d. Select the 2, 20 and 200 volt ranges and apply
the required voltages as specified in Table 3-3.
Verify that the readings are within specifications.

Voltage

100.00 mv

2v

1.0000 v

10.000 v

100.00 v

1000.0 v

AC Volts Checkout.

Set the calibrator frequency to

Allowable Reading at

180 to 2rc

99.6 to 100.4

.996 to 1.004

9.96 to 10.04

99.6 to 100.4
996 to 1004

1kHz.

100

a. Select dc voltage readings with the AC/DC and

V pushbuttons.

b. Connect the DC Calibrator (Item A, Table 3.1)

to the instrument.

c.

Select the 200mV range, and apply positive
1OOmVdc to the OMM. The reading must be within the
limits specified in Table 3-2.

d.

Select each remaining range and apply the

required voltage as specified in Table 3-2, verify

that the reading is within specifications.

e. Repeat all checks with negative voltage.

3-2

e.

To check the
Calibrator Amplifier (Item C, Table 3-l) to the
output of 1000 volts ac rms and verify that the OMM

reading is within the specified limits.

AC Voltage Performance Check

Applied

Range

200mV

20 v

200 v

1000 v

2v

Voltage

100.00 mv

1.0000 v

10.000 v

100.00 v

1000.0 v

1000

volt range, connect the AC

TABLE 3-3

Allowable Reading at

18’ to 28’C

98.7 to 101.3

.987 to 1.013 V

9.87 to 10.13 V

98.7 to 101.5

987 to 1013

mV

V

V

I

MODEL 169

PERFORMANCE VERIFICATION

3-13. Resistance Checkout.

a. Select resistance readings by pressing the n

pushbutton.

b. Select the 2000 range.

C. Connect the decade resistor (Item 0, Table

3-1) to the OMM.

d. Set the decade resistor to zero and measure
the resistance of the test leads.
reading from the display in all of the following
steps.

Set the decade resistance to

e.
that the reading is within the limits specified in

Table 3-4.

f. Continue the resistance check by selecting the

next range and measuring the next resistance as
specified in Table 3-4.
within specifications.

Resistance Perfonance Check

Ran e

Resistance

Verify that the reading is

Test each item in the table.

TABLE 3-4

Allowable Reading at

Subtract this

190.0.

18’ to 28’C

Verify

3-14. DC Current Checkout.

a. Select dc current readings with the AC/DC and

A pushbuttons.

b. Connect the dc current source (Item E. Table

3-1) to the

C.

lOO.OOpA to the OHM. The reading must be within the

limits in Table 3-5.

d. Select each range and apply the required cuv­rent as specified in Table 3-5.
reading is within specifications.

3-15. ANALYSIS.

3-16.
limits given in Tables 3-2 through 3-5. either
troubleshooting and repair or
described in Section 6, may be required.
recalibration will only be the indicated solution
when the instrument is out of speciflcbtlon on ~lofe
than one function (except for the higher ranges of
DC volts which are tht most critical).
instrument is still under warranty, refer to the
Note in Paragraph 3-2.

DMM.

Select the 200uA range and apply a current of

Verify that the

If the instiwwnt is out of the specified

calibration, a5

NO~Il~lly,

If the

kn

kn

kn

190.0 ”

1.9OOkn

19.0Okn
190

.Okn

200 n

r--t--

2

20

200

I

189.1

to

190.9 n

1.695 to 1.905 KZI

18.95 to 19.05

189.5 to 190.5

Kn

Kn

1895 to 1905 Kn

9.19 to 10.21

Mn

DC Current Performance Check

Applied

Range current

PA

nA

mA

mA

mA

100.00

1 .OOOO

10.000

100.00

1000.0

200

2

20

200

1000

TABLE 3-5

Allowable Reading at

18' to 28°C

"A

mA

mA

mA

mA

99.1 to 100.9

.991 to 1.009 mA

9.91 to 10.09 mA

99.1 to 100.9 mA

991 to 1009 mA

uA

3-3

MODEL 169

ACCESSORIES

SECTION 4.

4-l. GENERAL.

4-2.

This section describes the various accessories
and options available for use with the Model 169
OMM .

4-3.

MODEL 1600 HIGH VOLTAGE PROBE.

4-4. The Model 1600 High Voltage Probe (shown in
Figure 4-l) extends the measurable dc voltage range
up to 40 kilovolts. It has a 1OOO:l division ratio,
so that a reading of 1 volt on the DMM corresponds
to 1 kilovolt (1000 volts). To "se the probe,
select DCV and the required range, connect the high
voltage probe banana plug to the instrument, connect

the alligator clip to soui-ce low, and touch the

probe tip to source high.

WARNING

t

Be sure the alligator clip is connected to
source low before touching probe tip to
souw? high. A shock hazard or damage to

instrument may result.

Specifications

Voltage Range:

input Resistance:
Division Ratio: 1OOO:l.
Ratio Accuracy:

t1.5% at 25kV, decreasing to
Q.O% at 20k" and 30k",
e3.04 at 1OkV and 40kV, and

t4.0% at

Ratio Stability:
Heating Effects: Self-heating due to application

of high voltage for period in excess of 1 minute
will cause a maximum of 0.2% additional error at
40kV (error is less at lower voltage).

IkV.

0 to 40,000

1000 megohms.

?O.Ol%

per Y; *0.1x per year.

volts DC.

ACCESSORIES

4-5.

MODEL 1651 50-AMPERE SHUNT

4-6.

Figure 4-2) permits current measurements of up to 50
amperes ac or dc.

0.001 ohm ?l%, so that a 50-ampere current vill car­respond to a reading of 50 millivolts (0.0500 volt).
Set the "NM to ACV or DCV and select the required
rangc. TO use the shunt,

nished with the shunt from the shunt screw terminals
to the OMM input terminals. Use separate leads (not
furnished) to connect the source to the hex head
bolts. Be sure to use leads with a capacity of 50
amperes, or as needed.

4-7.

4-8.

leads with banana plugs at one end and spring-action
clip-on probes at the other end. TO use, insert the
banana plugs into the "NM and attach the prober to
the source.

4-9.

4-10.

permits measurement of dc voltages dt frequencies of
20 kilohertz to 100 megahertz. Connect the probe to
the input terminals and select 3CV and the appro­priate range.

Specifications

The Model 1651 50-Ampere Shunt (shown in

The shunt has a resistance of

connect the leads fur-

MODEL

1681

CLIP-ON TEST LEAD SET

This set (shown in Figure 4-3) contains two

MODEL 1682 RF PROBE

The Model 1682 RF Probe (shown in Figure 4-1)

Voltage Range:
Transfer Accuracy: i0.5dS. 1OflkHr to 10OWr peak

responding calibrated in rms of d sinewave.

Input Impedance: 4 megohm shunted by 3pF.
Maximum Allowable input: 30V rms AC, ZOOV DC.
Accessories Supplied: straight-tip, hook tip,

ground clip, hi adapter, banan; plug adapter.

0.25 to 30 volts nns.

4-1

ACCESSORIES

I

MODEL 169

4-11.

4-12.
test leads and 12 screw-in adapter tips. The tips
consist of two alligator tips with boots, two banana

plugs, two needle tips with chucks, two spade lugs

and four heavy duty tip plugs which permit con-

nection of the DMM to virtually any source within
its measurement range.

4-13. MODEL 1684 CARRYING CASE.

4-14. The Model 1684 Carrying Case (shown in Figure
4-4) is a hard vinyl case with a fitted foam insert
to help protect the Model 169 from damage. There is
also room in the case for the Instruction manual and

small accessories

4-15.

4-16.

(shown in Figure 4-2) permits measurement of ac

current by clamping around a single conductor,

eliminating the need to interrupt the current path.
Plug the ac current probe into the OMM and select

MODEL 1683 UNIVERSAL TEST LEA0 KIT.

This kit (shown in Figure 4-3) contains two

MODEL 1685 CLAMP-ON AC CURRENT PROBE.

The Model 1685 Clamp-On AC Current Probe

ACV and the appropriate range. The DMM will display

0.1

volt rms per ampere.

4-17. MODEL

4-18. The Model

(shown in Figure 4-3) consists of two .9lm (36
inches) test leads with probe tips terminated in
banana plugs.

4-19.

4-20.

parts that will mdintain up to
one year. The parts we listed in Table 7-l of
Section 7, Replaceable Parts.

4-21. MODELS

4-22.

permit mounting one or two Model

19-inch rack for convenient viewing.

1691

GENERAL PURPOSE TEST LEAD SET.

1691

General Purpose Test Lead Set

MODEL

1699

SPARE PARTS KIT.

The Model 1699 contains a complement of spare

10

Model

169

DMMs for

1010

and 1017 RACK HOUNTING KITS.

The rack mounting kits (shown in Figure 4-4)

169 DMMs

in

a

FIGURE 4-l. High Voltage Probe and RF Probe.

MODEL 169

ACCESSORIES

MODEL 1651

50.AMPEKE SiiUIIT

CLAMP-ON AC CURRENT PROBE

MODEL 1685

FIGURE 4-2.

Current Probe and Current Shunt.

MODEL

CLIP-Ok TCST LEAD SET

MODEL 1691

GE,,ER,,L PURPOSE TEST

1681

LEAD SET

MODEL 1683

UNIVERSAL TEST LEAD KIT

FIGURE 4-3.

Convenience Cable and Connectors.

4-3

ACCESSORIES MODEL 169

I

\- /’

MODEL 1684

CARRYING CASE

FIGURE 4-4. Carrying Case and Rack Mounting Kits.

“; :

;:I

:o i

SINGLE RACK I~lOIINTIllT; KIT

MODEL 1010

DUAL RACK ElOUNTIN(; KIT

I

4-4

I

MOOEL 169

TtlEORY OF OPERATION

I

I

SECTION 5.

5-1.

GENERAL.

5-2. This section contains circuit descriptions for

the Model 169 OMM. An overall block diagram of sig-

nal flow is provided in Figur‘e 5-I.
schematic diagram, drawing 301800, is contained in
Section 7 of this m~nudl.

5-3.

OVERALL OPERATION.

5-4.

As shown in Figure 5-1, the heart of the Model
169 is d single chip A/D converter with built-in
liquid crystal display drivers.
reading is the ratio of two floating input voltages
to this converter.
one voltage (Reference) is IOOmV. The other voltage
(VINHI) is the unknown input cuwent 01‘ voltage

to the Model

the input signal conditioning circuitry to a dc
Voltage between zero and ?200m".
reading is then determined by the formula:

(YINHI +

also automatically determines the polarity of the
input signal and detects whether an overrange
condition exists
displayed, plus is implied, and an ove~~ange is
displayed by a I with the last three digits blanked.
The annunciators ape displayed by the combination Of

range dnd function switching, and the decimal point
is positioned by the range switching.

For the ohms function, d reference resistor is

5-5.
placed in series with the unknown resistor and a

voltage is applied.
through both resistors, the ratio of their voltages
is the sdme as the ratio Of their resistances.

Thus, the voltage w1‘oss each resistor is measured

by the A/O converter and their ratio is displayed
per the formula: IO00 (VR, i VRREFERENCE).

169

VREFERENCE).

On all functions except ohms,

which is converted and/or scaled by

The

(>1999

counts).

Since the Same current flows

The overall

The displayed

The displayed

1000

Conwrter

A/O

A minus sign is

THEORY OF OPERATION

5-6. SIGNAL CONDITIONING.

5-l. AC/DC Voltage Measure,wnts.

5.8. For voltage measurements, ds shown in Figure
5-2, the input is divided by
10,000 by the IO megohm resistive divider.
resulting output from the divider is d 0 to 200mV

voltage.
direct to the A/D co"vel‘teP along with the IOOmY
reference.
gain or attenuator stages are used. the dc dccurdcy

is determined primarily by the precision resistor

accuracies (actually their ratios) and the reference
adJ"stment.

5-9. For an x input, the output of the resistive
divider is first applied to the AC Converter.
AC conver‘ter is a half wave rectifier with IOOUV

resolution and sufficient gain to provide d positive

dc output voltage equivalent to the nns value of d
sinusoidal input.
lOOmVac, the output will be IOOmVdc. The important
gain determining elements of the converter dw

precision resistors so that d gain adjustment is not
required.

5-10.

5-11.

5-3, the appropriate shunt resistor is placed across
the OMM input in accordance with the selected range.
As with voltage medsurcments, the voltage drop
across the current shunt is designed to be 2OOmV for
a full scale input current on any range. Therefore,
after the input current is converted to d voltage,
the meaSUPement process for current is identical to
that for voltage measurements.

Current meaSurCments is primarily determined by the

ilccUrXies of the precision shunt resistors and the
reference adjustment.
ac accuracy along with any error contributed by the

AC Converter.

For a dc input, this voltage is applied

It should be noted that, since no active

Thus, for sinusoidal input of

AC/DC Current lkasuremnt.

FOT Current medsurements, its Shown in Figure

These two items also affect

1, 10, 100, 1000, or

Accuracy for dc

The

The

5-1

THEORY OF OPERATION

MOOEL

169

5-12.

5-13.
the voltage drop across the unknown resistance to
the voltage drop of an internal reference resistor
as shown in Figure 5-4. For this ratio measurement
technique, d voltage is connected to the input
divider used for voltage measurements and the range
switching selects a l/2 of full scale value refer­ence resistance to be placed in series with the
unknown resistor.

pared by the A/D converter and displayed on the LCD.

A 2 kilohm thermistor (RTlOl) provides overvoltage

input protection for the low resistance ranges and

it is in series with the reference resistor and the
unknown resistor on all but the 20 megohm range.
For this reason, the +V (t2.8V nominal) top of the

reference is selected on the 200 ohm range. On all
other ranges tl.ZV is used. Since a ratio technique

is used,
determine the
measurements, and no adjustments are necessary.

5-14. A/D CONVERTER.

5-15.

verter and display drivers ape contained on a single
integrated circuit (U102). This chip also contains
an oscillator and the regulators that are used to
establish the analog and digital grounds.
components are used to establish the timing and
reference levels required far A/O operation.
employs the dual slope principle of A/D conversion.
This method provides d ~asurement cycle consisting
of three consecutive time periods, autozero. signal
integrate and reference integrate (read).
for these periods, and thus the measurement period,

is a function of the oscillator frequency.
oscillator components are selected to provide 40 kHz
which results in a
period for best rejection of 50Hz and 60Hz. To
begin each measurement cycle. the autozero period is
set to a minimum of
period, the reference voltage input to the A/D is

Resistance

Resistance measurements are made by comparing

actual values of the reference resistors

As shown in Schematic

Measurements.

The voltage drops are then com-

primary accuracy for

301800,

100

millisecond signal integrate

100

milliseconds.

resistance

the A/O con-

External

During this

u102

Timing

The

stored on capacitor
referenced to analog cornnon.
is then stored on capacitor Cl02 for use during the
remainder of the measurfment cycle, if any amplifier
offset exists. The second phase of the measurement
cycle is the 100mS signal integration period as
previously mentioned.
differential voltage between IN HI and IN LO is
integrated.
of the integrated signal is also determined.
final phase is reference integrate, or read. During
this period,
reference capacitor will be connected with the
correct polarity to return the integrator output to
the autozero level.
output to return to this level is proportional to
the unknown input signal.
from zero to 200 milliseconds. corresponding to
displayed counts of zero to 2000 full scale as
determined by
input signals less than full
cmwrtw rewrts to wtozero far the remainder of
the reference integrate period.
measurement cycle is 400ms. which results in a
display update rate of 2-l/2 per second.

5-16.

5-17.
associated circuitry is shown in Schematic
As previously mentioned, the seven segment decoders
and drivers are provided by the A/D converter chip
u102.
on the output lines to the LCD.
driven by a square wave having the same amplitude
and frequency as the BACKPLANE line (nominally 0 to

t5V at 50Hz).
ments are driven out of phase with BACKPLANE the
segments are ON.
segments are OFF.
points are turned ON and OFF similarly, with the
phasing of their lines controlled by the range and
function switches through logic gates. A swnary of
annunciator switching is given in Table 5-1.

At the end of this period, the polarity

DISPLAY CIRCUITS.

The liquid crystal display (LCD) and its

The digitized measurement data is presented

Cl11

and the A/D converter is

A correction voltage

During this period, the

The

internal circuitry ensures that the

The time required for the

The read period can be

1000 (VI, + VREF).

scale,

Thus,

a complete

FW

the A/D

301800.

These lines are

When the lines to the display seg-

Conversely. when in-phase the

The annunciators and decimal

5-2

MODEL 169

THEORY OF OPERATION

5-18.
5-19.

lated and calibrated) to the A/D converter for

voltage and current measurements.
approximately 2.8V to the 2008~ range and approxi­mately 1.2V to all other n ranges during resistance
meas"rements. The heart of the reference source is
a band-gap reference (VRlOl) that regulates the

voltage to a value between

approximately SOOvA.
applied to the reference source depends on the

internal regulator in the A/O converter which
establishes analog ground nominally 2.8 volts below
vt. Thus, the value of RlOZG is selected to provide

a minimum current of 400uA to "8101 to ensure a good
temperature coefficient.
tion adjustment,
adjustment span and are stable precision resistors
to ensure the 1 year calibration cycle.

5-20.

5-21.

tor switch (QlO2) which compares the negative supply
to digital cornnon (ground). 9102 is set for a nomi­nal supply voltage of 6.9 volts. (Actual battery
voltage will be about 7.2 volts due to the drop of
CRlO5.) In the Model 169, the primary limit to bat­tery usefulness is the integrator swing on the high
ohms ranges with a full scale input. For this rea-

son, the low battery indicator (RAT) should turn on
with a battery voltage of 6.5 volts, or above, for
the proper functioning of the A/O Converter and the

low battery indicator.

5-22.

5-23. Effective input protection circuitry has been
designed into the Model 169 which provides protec­tion against accidental input overloads on all
functions and ranges.
in the following paragraphs for each function.

REFERENCE SOURCE.

The reference source supplies lOOmV (regu-

It also provides

1.20 and 1.25 volts at

Recall that the voltage

RlOl

provides the calibra-

while R1020 and R102E limit the

LOW BATTERY DETECTOR.

The low battery detector is a simple transis-

INPUT PROTECTION.

This circuitry is described

5-24. Voltage Protectlo".

5-25.
during dc voltage measurements by limiting the cur­rent to *ImA.

5-26.
tected by using R107 for current limiting and CR103
and CR104 to clamp the voltage to digital cornnon and
vt.
through ClD7,

5-27. current Protection.

5-28.
opens for input current overloads with up to 250
Volts.

Clamp the input voltage to about 1 volt until F101

"PWS.

5-29. Ohms Protection.

5-30.
basic components used to provide protection during

resistance meas"reme"ts.
leakage zener to clamp any unintentially applied

voltage to ground. RTlOl is a positive temperature
Coefficient thermistor which bears the applied volt­age by increasing its resistance. This timits cur-

rent to

of the A/O converter as in OC volts.

Voltage across 9101 can

tive
tects REF HI by limiting the current to +lOOuA.
Since
tected by RlOZG on the 200n range and by R102F plus
the divider resistance on the other ranges.
negative input overloads the circuit operates the
same, except
to ANALOG COMMON.

R107 and K103 protect the A/D converter

For ac voltage medsuremeotn, UlOI is pro-

Overload currents are returned to anal09 cornnon

Cl13

and the AID converter.

On the higher current ranges,

On the lower current ranges, CR106 and CR107

Transistor

4101

and thermfstor RTlOl are the

9101

protect

supply.

YRlOl has a current

QlOl.

R102C protects REF LO dnd RlOKE pro-

qlO1

RlO3 is used to protect IN Hi

be 10 volts above the posi-

limit of IOmA. it is pro-

is then forward biased and clamps

FlOl

(2A. 25OVl

is used as d low

Since the

For

5-3

THEORY OF OPERATION

MOUEL 169

TABLE 5-1

Annunciator Truth Table

\NN!JNCIATOR

BAT

AC

DPl

DPZ

DP3

V

a

k

SWITCH

Q102

DC/AC

R

2K

20K or 20M

200

or ZOOK

V

a

200

and 20M

R

CONDITIOh

OFF

AC
OFF

ON

ON

ON

ON

ON

OFF

ON

20M

A

A and 200

A

1.
200

V and 200

2.

I

5-4

ON

ON

ON

ON

OFF

ON

MODEL

169

THEORY OF OPERATION

INPUT

HI>

NOTES: 1.

n

TO CKTS

Output voltage from current shunts

and voltage attenuator are zen, to

200mVAC and zero to t200mVdc.

,-, +2.8V

AND ANNUNCIATOR

200n

DIGIT
SECML,,T

DATA

DISPLAY

t

2. Output of AC Converter is zero to
+2OOmVdc.

FIGURE 5-1.

Model 169 DMM Overall Signal Flow Block Diagram.

’

THEORY OF OPERATION

MODEL 169

DECADE

RESISTIVE

DIVIDER

LO

9M

900K

90K

+

FIGURE 5-2.

0v to t200mV

Simplified AC/LX Voltage Measurement.

I

5-6

HI

INPUI 0

MODEL 169

CURRENT

SHUllTS

zooun

900

2oA

90

2omA

LO>---

200mR

2oooaiA

0

RANGE

S~IITCHING

FIGURE 5-3.

9

.9

.l

Simplified AC/DC Current Meaurement.

THEORY OF OPERATION

REFERENCE

SOURCE

MODEL 169

I

100.1

90K

900K

9M

9K

200

2K

20K

200K

2000K

20M

RANGE

SWITCHING

0

.

RTlOl
2K

,C c

I

5-8

RX

HI

-1n
A

REFERENCE

RESISTORS

FIGURE 5-4. Simplified Resistance Measurement.

I

MODEL 169 MAINTENANCE

SECTION 6. MAINTENANCE

6-l. GENERAL.

6-2. This section contains information necessary to maintain

the Model 169 DMM. AdjustmenVcalibration, troubleshooting,

battery replacement, fuse replacement and LCD replacement
procedures are provided.

6-3. CALIBRATION.

6-4. Calibration should be performed yearly (every 12 months)
or whenever Performance Verification (see Section 3) indicates

that the Model 169 is out of specifications. If the Calibration Pro-

cedure cannot be periormed properly, r&r to Troubleshooting
information in this section or contact your Keithley representa-

tive or the factory.

NOTE
Calibration should be performed by qualified Peru
sonnel using accurate and reliable equipment.

6-5. Recommended Calibration Equipment.

6-6. The Fluke Model 341A DC Calibrator is recommended for

calibrating the Model 169. Alternate calibration equipment may
be used. However, the accuracy of the alternate 190 mVDC

source must be .025% or better.

a. Turn off power and disconnect ail leads from the 169 DMM

Input.

b. Loosen the four screwy in the bottom of lhe DMM until lhe

threads are disengaged. NOTE: These screws are not rep
tained and they will fall out when the DMM 1s returned to
the upright position.

c. Hold the top and bottom cover together to prevent ihew

separation and turn the DMM over lo !ls normal p&Ivan.
Remove the top cover.

d. Turn power on by depressing the ON/OFF pushbutlon.

and verify that the low battery indicator (BAT) does not apt
pear. (NOTE: It is recommended that fresh batteries be ins
stalled at this time to provide the longest possible use of
the Model 169 before additional maintenance is required.
Refer to Installation of Batteries, Paragraph 2-6).

6-11. Calibration Adjustment.

6-12. Only two adjustments are needed to calibrate the Model

169. Proceed as follows:

a. Place the Model 169 on the 200mVDC range.

6-7. Environmental Conditions.

6-8. Calibration should be performed under environmental con-

ditions having an ambient temperature of 23” i2”C and a rela­tive humidity lessthan 70%. If the Model 169 has been exposed
to extremes of temperature or humidity, allow at least one hour
for the instrument to stabilize.

6-9. Case Cover Removal.

6-10. To gain access to the calibration pot and circuit compo­nents, remove the case cover as follows:

WARNING
Disconnect all te?,t circuits from the INPUT connec­tions of the Model 169 before removing the case
CO”H.

b. Apply-190.0mVDCandadjusf RlOl (see Figure&l)far a

reading of -190.0.

c. Apply +19O,OmVDC and note reading.

d. Adjust I?1 01 for a reading halfway between the noted read-

ing and 190.0 (e.g., if noted reading is 190.2, adjust Al01

for a reading of 190.1).

e. Place the Model 169 on the ZVAC range.

f. Apply 1 .OVAC at 5kHz and adjust C1 17 for a reading be-

tween 1.025 and 1.035VAC. (The trimmer capacitor is lo­cated at the center of the PC board, between the ribbon ca­bles.)

6-13. This completes calibration of the Model 169. Reinstall the
DMM top cover and verify performance as outlined in Section 3.

MAINTENANCE

MODEL 169

SPACERS (21

CAL I

BRA; I ON
ADJUSTMENT
Rlcl

6-14.

6-15.

FIGURE 6-l.

TROUBLESHOOTING.

The following troubleshooting instructions

Calibration Adjustment Location.

are intended for qualified personnel having a basic
understanding of analog and digital

electronic

principles and components used in a precision
electronic test instrument.

Instructions have been

written to assist in isolating the defective circuit
or Subcircuit.
component has been left to the technician.
the case cover ds explained in Paragraph 6-9 to gain

access to

locations.

Isolation of the specific defective

circuit

components

and test

Remove

point

6-16. Special Handling of Static Sensitive Devices.

6.17.

CMOS devices a-e designed to function at very
high impedance levels for low power consumption.
For this reason, a normal static charge build up on

your person or clothing can be sufficient to destroy

these devices.

The following steps list the static

sensitive devices in your Model 169 and provide
instruction on how to avoid damaging them when they

must be removed/replaced.

6-Z

I

MODEL 169

MAINTENANCE

a. Static sensitive devices:

Kfithley

Part Number

LSI-22

IC-102
IC-226
IC-228

OZ-62

b.

The above integrated circuits should be
handled and transported only in protective con­tainers.
tubes or static protective foam. Keep the devices
in their original containers until ready for use.

c.
tainers only at d properly grounded work bench or
table, and only after grounding yourself by using a
wrist strap.

d. Handle the devices only by the body.

touch the pins.

e. Any printed circuit board into which a device

is to be inserted must a'150 be grounded to the bench

or table.

f. Use only anti-static type solder suckers.

g. Use only grounded tip soldering irons.

h. After soldering the device into the board, or

properly inserting it into the mating receptacle,

the device is adequately protected and normal

handling can be resumed.

Typically they will be rcceivcd in metal

Remove the devices from their protective con-

Reference

Designation

u102

u103

IJ104, u105

“106

VRlOl

DO not

6-21.

Display Driver circuit should be verified before
troubleshooting the signal conditioning circuits.
Check these circuits per Tables 6-2 and 6-3. If it

is determined that the Liquid Crystal Display is
defective,
6-31.

6-22.

6-23.

Converter circuitry.

Proper Operation of the A/D Converter and

replace per instructions in Paragraph

AC

Converter.

Problems with dc voltage may

Check this circuit per Table

involve

the AC

6-4.

6-24.

Circuit.

6-25.

may involve these Signal conditioning circuits.
Check out the Reference Source and Ohms Circuit per

Tables 6-S and 6-6.

checked by measuring the resistance of each resistor
individually with the instrument off and the push­buttons in the out position.
Voltage Divider resistors are as follows:

Voltage Olvlder. Reference Source and Ohms

Problems with voltage or resistance ranges

The Voltage Divider can be

The tolerances of the

a. R108, 100.1n, 0.1%

b.

A109, 900n, 0.1%

c. RllO,

d.

e. H112, 900Kn,

f. R113, 9Mn, 0.08%

Rlll,

9Kn, 0.1%

90Kn, 0.1%

0.1%

6-18.

6-19. In general,

6-1,

and power supply are providing the correct voltages
to the electronic components.
that the battery needs replacing, refer to Paragraph
6-33, Battery Replacement.

6-20. A/O Converter and Oisplay Driver.

Power supply.

start troubleshooting with Table

Power Supply Checks, to verify that the battery

If it is determined

6-26. current Circuitry.
6-27.

check the current circuitry ds directed in the fol­lowing pangraphs.
the current shunts are cornnon to both ac and dc cvr­rent,

current ranges if there is d fault in the current

shunt circuitry.

If problems occur with current readings.

It should be noted that, since

problems should exist on the same ac dad dc

6-3

MAINTENANCE

MODEL 169

6-28.
simultaneously depressing the A and n pushbuttons
while on the 2K range.
good fuse is nominally .lOOmAKn. A blown fuse Will
be indicated by an overranged display.
current fuse is blown, replace per instructions in
Paragraph 6-35.

6-29.

suring the resistance of each resistor Individually

with the instrument off and all the pushbuttons in

the out position.
as follows:

The cuwent fuse can be checked wt by

The display reading for a

If the

The Current Shunts can be checked by "ea-

The tolerances of the shunts are

a. R114A, 0.9Q, 0.5%

b. R1146, 0.10, 0.5%

c. R115, 9n, 0.5%

d. R116, 90n, 0.1%

e. R117, 9OOfl. 0.1%

6-30.

and CR108) as follows:

resistor to the input of the Model 169.

or less.

6-31. LIQUID CRYSTAL DISPLAY REPLACEMENT.

b-32.
Figure 6-4, to replace the display of the Model 169.

graph 6-9.

to the front panel.

careful of the LCII display (Keithley Part NO. DD-18)

as it will be loose and may fall out of the front
panel.

Check the current protection diodes (CR107

a. Select ZOO,,AOC range.

Apply 5VAC through a IKn current limiting

b.

Clamping across the diodes must occur at tlV

c.

Perform the following procedure, referring to

Remove the case cover as explained in Para-

a.

b. Remove the three 318" pal nuts holding PC-509

Separate PC-509 from the front panel being

c.

6-4

I

FIGURE 6-2.

CONNECTOR

(CS-376-1)

LCD Assembly.

I

MODEL 169

TABLE 6-l

Power Supply Checks

STEP / ITEM/COMPONENT REQUIRED CONDITION' REMARKS

1

Battery Voltage 7.5V min.

2 CR105 0.5V drop max.

MAINTENANCE

3 UlO2, pin 40 and 15 7.OV min.
4 Cl07 2.4 to 3.2V output Of u102

0.8 to 2.6V output of u102

!

'Above checks with fresh batteries and power switch ON.

TABLE 6-2

A/O Converter

STEP ITEM/COMPONENT

1
2 Display Short input, 00.0 tld
3 Refewnce (UlO2, pin 5)

REWIRED CONDITIONS' REMARKS

power ON, ZOO","DC ,uan9e

Nominally 98mV using

voltmeter with 1OMn
Input Impedance

Supply to u102

(Analog Gnd)

(Oigital Gnd)

I

rero Check

IHigh ImpeddnCP
reference

4 Ratio Test Short "102 pin 5 to

5 Display

6 UlO6, Pin 3

7 External Voltage source

8 u102 Pin 14 to Input Lo

*Measurements made with respect to input lo

**Non-symmetrical in most cases

pin 10

100.0

*2d

40kHz f6kHz**

Approx. 5Vp-p

Apply +190.0mVAC Calibration

See waveform (Figure ,ntegrator

6-3) Check

connects refer­ence to Input

If steps 3 and
5 are Correct
AID Converter

is functioning
properly

Clock check

poi nr

6-5

MAINTENANCE

MODEL 169

190mVDC Input

FIGURE 6-3.

STEP

1
2 "102 pin 40 to pin 4 4.0 to 6.0 Volts
3 "102 pin 3 to Input Lo 4OkHz +6kHz Clack Check

4 U102 pin 20 to Input Lo

5 UlO2 - any display Approx. 50H.7 Square

6 U104, U105, UlO6,

ITEMICONPONENT

driver line wave, approx. svp-p backplane for

decimal point and wave, approx. svp-p

annunciator driver
lines

Integrator Waveform.

TABLE 6-3

Display Driver

REQUIRED CONDITIONS REMARKS

Power ON

Digital Supply

Apprax. S'ip-p

Approx. 50Hz Square

wave, approx. svp-p

In phase with

seqment Off,
out of phase
with backplane

for segment on

Approx. 50Hz square

6-6

I

MODEL

169

MAINTENANCE

TABLE 6-4

AC Converter

STEP

c-

1

2

UlOl

External "oltagc Source Apply 1OOmVAC at 100Hz
Cl08

Ulol pin 6 to Input Lo

6

UlOl pin 6 to Input Lo

7

ITEM/COMPONENT REQUIRED CONDITIONS

Power 01,. 20h"AC Kangc

pin

7 to

pin 4

7V min.

98mVOC Nominal using

1OMfl input impedance
voltmeter

See Waveform (Figure

6-4)

Short Input

*SmVDC offset max.

Supply Voltage
Calibrated Input
IHigh Impedance

+440mV-

1OOnVAC Input

FIGURE 6-4.

AC/DC Converter Waveform.

6-l

MAINTENANCE

TABLE 6-5

Reference source

MODEL

169

STEP ITEM/COMPONENT

1
2 U102 pin 40 to Input Lo

VRlOl

3

4

STEP

(<lOOpf probe)

R102

pin 8 to Input Lo

ITEM/COMPONENT

REQUIRE0 CONOITIONS

power ON

2.4 to 3.2 "DC

1.2 to 1.25v
Nominally 1OOmVDC using

voltmeter with ,lOMn
input impedance

TABLE 6-6

Ohms Circuit

REQUIRE0 CONDITIONS* REMARKS

REMARKS

Output Of u102

(Analog Supply)

Reference sourc

e

6-8

1

2 RTlOl l.OKn to 3.OKn (can

3 Reference Resistors R108 thru R113 can

4 Power ON, 200n

5

(1101

'Do not remove RTlOl unless absolutely necessary because the leads fall

off device easily while soldering.

Power OFF, DCV func-

tion, all range
buttons out

now be checked in
circuit)*

be checked in cir- R109 affects 2Kn range
wit for
XC"t-KY

range, Input open

0.1%

‘2 Volts across

errmitter ­collector junction

Resistance Check

R108 affects 2005, range
RI10 affects ZOK" range

Rlll

affects 200Kn range

It112

affects 2000Kn ran<

R113 affects 20Mn range

Voltage drop check

MODEL 169

d. Make sure the rubber gasket is in place before
placing the new display in the slot of the front
panel.

e. The zebra strip should be installed after the

new display is placed in the front panel window.
Care must be taken to assure the zebra strip is kept
clean. The zebra strip should be aligned such that
the black stripes contact the conductors on the
display and the conductors on PC-509.

f. Reassemble PC-509 and the front panel using
the three 318" pal nuts.
are snug.

Turn the unit "ON" and check the display to

'3.
see that it is working properly. If the zebra strip

is not aligned properly or if it is dirty there will

be some segments on the display that will not light.

Tighten them until they

K-33. BATTERY REPLACEMENT.

6-34. The low battery indicator will automatically
come on with approximately 5% of battery life
remaining (20 hours for carbon-zinc and 40 hours for
alkaline cells). Replace per directions in Para-

graph 2-6.

6-35. CURRENT FUSE REPLACEMENT (Figure 6-5).

t

To prevent a shock hazard, disconnect all

circuits from the Model 169 INPUT termi-

nals before removing current fuse.

6-36. To remove the current fuse, turn the DMM over
and lay it carefully on its top. Insert d small

screwdriver blade into the slot on the fuse holder,
press gently and turn l/4-turn counter-clockwise.

Lift the holder and fuse out of the receptacle. The
fuse can now be removed for checking or replacement.
Replace with one of the following types:

WARNING

'FIGURE 6-5.

Installing a higher rated fuse than the
one specified could result in damage to
the instrument.

Current Fuse Removal/Replacement.

A

CAUTION

a. U.S.A. Use - 3AG, 25OV, 2A, Normal Blow

b. Europe Use - 5 x 20mm, 25OV, 2A, Normal Blow

6-9

I

MODEL 169

SECTION 7. REPLACEABLE PARTS

REPLACEABLEPARTS

7-i. GENERAL.

7-2. This section contains information for ordering replacement
parts. Panel and covers are shown separately on Figure 7-l.
The Replaceable Parts List is arranged in alphabetical order of
the Circuit Designations of the components.

7-3. ORDERING INFORMATION

7-4. To place an order or to obtain information concerning re­placement parts contact your Keithley representative or the fac­tory. See the inside front cover for addresses. When ordering,

include the following information:

a. Instrument Model Number.

b. Instrument Serial Number.

c. Part Description.
d. Ci’cuit Designation (if applicable).
e. Keithley Part Number.

7-5. FACTORY SERVICE.

7-6 If the instrument is to be returned to the factory for service,
please complete the Service Form which follows this section,
and return it with the instrument.

7-7. SCHEMATIC.

7-8. The Model 169 3.112 Digit DMM: Schematic No. 30180D.

7-9. COMPONENT LAYOUT.

7-10. Model 169 PC-506 Component Layout No. 301760.

7-11. MODEL 1699 SPARE PARTS KIT.

7-12. A spare parts kit is available that contains a complement

of spare parts that can maintain up to ten Model 169’s for ap-

proximately one year. A list of the spare parts is given in Table
7-1.

TABLE 7-1

Model 1699 Parts List

iiy

Keithley P/N

-

2

IJZ-62.

2

FH-12

5

FU-13

5

FU-48

1

IC-1028

1

IC-226’

2

IC-227

1

IC-228*

1

LSI-22’

1

R-277.9M

3

RF-28

2

RF-34

1

RF-39

1

RT-5

3

TG-47

-

‘Anti-Static Protection and Handling required. Refer to Section 6 of
this Manual for Special Handling Procedures for Static-Sensitive

Devices.

Schematic Designation
VRlOl

Fuse Holder

FiOl (3AG)
FlOl (5mm,x 20mm)
u103

u104, u105

UlOl
U106
u102

RI13
CR101 thru CR104

CR106, CR107
CR105

RTlOl
QIOI, Cl102

7-o

I

REPLACEABLEPARTS

MODEL 169

Table 7-2

REPLACEABLE PARTS LIST

Circuit
m?sig.

BTlOl
thru
BT106

Cl01
Cl02
Cl03
Cl04
Cl05
Cl 06
Cl07
Cl06
Cl09
Cl10
Cl11
Ci12
Cl13
Cl14
Cl15
Cl16
Cl17
Cl16

CR101
CR102
CR103
CR104
CR105
CR106 Rectifier, Silicon, 3A. 50V
CR107

Description

Battery, 1.5V, “c” cell, Carbon Zinc

Cap., .luF, 16OV, Mstalized Polypropylene
Cap., .22uF, lOOV, Metalized Polyester
Cap., .047uF, IOOV, Metalized Polyester
Cap., .I uF, lOOV, Metalized Polyester
Cap., 4.7uF, 25V, Aluminum Electrolytic
Cap., .luF. lOOV, Metalized Polyester
Cap., 4.7uF, 25V, Aluminum Electrolytic
Cap., 1 .OuF, 16V, Aluminum Electrolytic
Cap., .02uF, IOOOV, Ceramic Disc
Cap., 3.3pF. 15OOV, Ceramic
Cap., .047uF, IOOV, Metalized Polyester
Cap., lZOpF, 5OOV, Silver Mica
Cap., 4.7uF, 25V, Aluminum Electrolytic
Cap., .22uF, lOOV, Metalized Polyester
Cap., 39OOpF, lOOOV, Ceramic Disc
Cap., 4.7uF, 25V, Aluminum Electrolytic
Cap., Adjustable (1.5pF, nominal)
Cap., O.luF. 5OV, Ceramic Film

Rectifier, Silicon, 75mA. 75V
Rectifier, Silicon, 75mA, 75V
Rectifier, Silicon, 75mA, 75V
Rectifier. Silicon, 75mA, 75V
Rectifier, Germanium 15mA. 25V

Rectifier, Silicon, 3A, 50V

Keithley
Part No.

BA-6

~ c-305-.047

c-305-.1
c-314-4.7
c-305.. 1

1 c-314-4.7

C-325-l
C-296-.02
c-30%3.3P
c-305-.047
C-320-1 IOP
c-314-4.7
C-305-.22
C-64.3900P
c-314-4.7
c-1 64
C-237-.1

RF-26
RF-28
RF-26
RF-26
RF-39
32453
32453

DSlOl

Liquid Crystal Display

Zebra Connector Strip

Fuse, 2A, 25OV, 3AG (U.S. Models)
Fuse. 2A, 25OV, 5 x 20mm (European Models)

Banana Jack, Red

Banana Jack, Black
Battery Connector

Transistor. NPN

DD-16
CS-376-l

FU-13
FU-46

BJ-1 l-2
BJ-11-O

BH-26

TG-47
TG-47

7-1

MODEL 169

REPLACEABLEPARTS

Table 7-2

REPLACEABLE PARTS LIST (Cont.)

Zircuit
Desig.

RlOi
RI02
RI 03
RI04
RI05
HI 06
RI07
RIO8
RI OS
RI10
RI11
Fill2
RI13
RI14

R115
RI16
RI17

RTlOl
SlOl

UlOl
u102
u103
u104
uio5
U106

Description
Potentiometer, 500 ohm

Thick Film Resistor Network

Resistor, 1 M ohm, 10%. 1 W. Comp
Resistor, lOkohm, .I%, .lW. MtF
Resistor,4,71kohm, .1%. .lW. MtF
Thick Film Resistor Network

Resistor, tOOk ohm, 10%. 2W. Comp.

Resistor, 100.1 ohm. .I% .lW, MtF

Resistor. 900 ohm, .I%, .1 W, MtF

Resistor. Sk ohm, .I%. .iW, MtF

Resistor,90kohm, .I%. .lW, MtF

Resistor, 900k ohm, .i%, .lW, MtF

Resistor, 9M ohm, .08X 2W. CMtF

Resistor, Dual

Resistor, 9 ohm, 5% l/ZW. MtF

Resistor, 90 ohm, .l%, 1/8W, MtF

Resistor, SOOohm, .I%, .lW, MtF

Thermistor, 2k ohm, 40% 8mA, 5OOV, PTC

Switch, 12 Station, Pushbutton

Low-Power JFET-Input OP~AMP

3-i/2 Digit Single Chip A/D Converter

CMOS Quad Z-Input NAND Gate

CMOS Quad Exclusive-OR Gate

CMOS Quad Exclusive-OR Gate

CMOS Quad Exclusive-NOR Gate

Keithley
Part No.

RP-97.500
TF-93
R-2-l M
R~283-10k
R-283~4.71 k
TF-92

R-3.IOOk
R~283-100
R-283-900
R..283~Sk
R-283.90k
R-283~900k
R~277-9M
R-278
R-61 -9
R~l79-90
R-283-900

RT-5
303148 ,sl

IC-277

?3.shwA-

IC-102’
IC~226’
IC-226”
IC-228’

I

7-2

VRlOl
VW 02

‘Anti-static protection and handling required

Diode, Low voltage ref, 1.2V. IOmA
Diode, Zener, S.lV nominal. .25W

DZ-62
DZ-14

I

REPLACEABLE PARTS

MODEL 169

FIGURE 7-1. Covers and Panels.

7-3

“I I “r I

OY

\

I -

SERVICE FORM

Model No.

Serial No.
Name and Telephone No.
Company

Lisl all control settings, describe problem and check boxes that apply 10 problem.

q

intermittent

q

IEEE failure

q

Front panel operational

Display or output (circle one)

q

Drifts

OLInstable

q

0verlond

lJCalihration only

q

Dara required

(autach any addilional sheets as necessary.)

q

Analog output follows display

q

Obvious problem on power-up

q

All mnges or functions are bed q Checked all cables

q

Unahle to xl-o

q

WiU not read applied input

UC of C required

q

l’anicular wngrt or function had: specify

q

Batteries and fuses are OK

Date

Show a block diagram of your measurement system including all instruments connected (wlxrher power is tumcd on or nor).
Also, describe signal source.

Where is the measurement being performed? (factory, controlled laboratory, out-of-doors. etc.)

What power line voltage is used? Ambient TenlperaturG

Relative humidity?

Any additional information. (If special modifications have been made by [he user. pleasc describe.)

Other‘?

B INSTRUMENTS

Model 169 Digital Multimeter Addendum

INTRODUCTION

This addendum to the Model 169 Digital Multimeter Instn~tion Manual is being provided in order to supply
you with the latest information in the least possible time. Pleaseincorporate this information into the

immediately.

Page 7-O; Replace Table 7-1 with the following:

Table 7-1. Model 1699 Parts List

manual

!&entity

1
5
5

1

1
2

1

1
i

2

1

1

1

‘Anti-Static Protection and Handling required. Refer lo the Model 169
Instruction Manual for Special Procedures for Static-Sensitive Devices

Keithley PIN

DZ-62*
FU-13
FU-46
K-102

10.226
IC-227
IC-226
LSI-122’
R277-9M
RF-26
RF-34
RF-39
UT-5

TG-47

Schematlc Designation
VRiOl

FlOl (3AG)
Fl 01 (5mm x 20mm)
u103
u104, u105
UlOl
U106
u102
R113
CR101 thru CR104
CR106, CR107
CR105
RT-101
Q102

MODEL 169

- RECOMMENDED SPARE PARTS

PART NUMBER DESCRIPTION

DZ-62

IC-102
IC-226
IC-227
IC-228

LSI-22

R-277-W
RF-28
RF-34
RF-39
RT-5

TG-47

DD-18C~
c179-4.7
BA-28
30169

30170

Diode

Integrated Circuit
Integrated Circuit
Integrated Circuit
Integrated Circuit
Integrated Circuit
Resistor
Rectifier
Rectifier
Rectifier
Thermistor
Transistor
Readout

Cap
Battery

Front Panel

Overlay

QTY

-

2
1

1

2

1

1

1

3
2

I
1
3
1
2

1
1

1

KH/ntb:09/10/82

m INSTRUMENTS

Model 169 Digital Multimeter Addendum

INTRODUCTION
Thisaddendum to the Model 169 Digital Multimeter Inshuction Manual is being provided in

you with the latest information in the least possible time. Pleaseincorporate this information into
immediately.

Page 7-O; Replace Table 7-1 with the following:

Table 7-1. Model 1699 Paris List

Quantity

i
5

1
1

2

1
1

1
3
2

1
1

r

1

Keithley P/N Schematic Designation
DZ-62’

FU-13
FU-48
IC-102’
IC-226
IO-227
K-228*
LSI-122
R277-9M
RF-28

RF-34
RF-39
RT-5
TG-47

VRlOl
FlOl (3AG)
FlOl (5mm x 20mm)
u103
u104, u105
UlOl
U106
u102

R113
CR101 thru CR104
CR106, CR107
CR105

RT-101
Q102

order

tosupply

the manual

‘Anti-Static Protection and Handling required. Refer lo

Instruction Manual for Special Procedures for Static-Sensitive Devices

the Model 169

m INSTRUMENTS

Model 169 Digital Multimeter Addendum

INTRODUCTION
Thisaddendum to the Model 169 DigitalMultimeter Inshuction Manual is being provided in order to supply

you with the latest information in the least possible time. Please incorporate this information into the
immediately.

manual

Page 7-O; Replace Table 7-l with

I

Zwantity

1

5

5

1

1

2

1
1

1
3
2

1

1

1

‘Anti-Static Protection and Handling required. Refer to the Model 169
instruction Manual for Swcial Procedures for Static-Sensitive Devices,

the

following:

Table 7-1. Model 1699 Parts List

Keithley PIN
DZ-62’

FU-13

FU-46
K-102’
K-226
IC-227

IC-228’
LSI-122’
R277-9M

RF-26

RF-34

RF-39
RT-5
TG-47

Schematic Designation
VRlOl

FlOl (3AG)

Fl 01 (5mm x 20mm)

u103
u104, u105
UlOl
U106
u102
R113
CR101 thru CR104
CR106, CR107
CR105
RT-101

Q102