Keithley 169 Service manual

Instruction Manual
Model 169
Digital Multimeter
01979, Keithley Instruments, Inc.
Cleveland, Ohio, U.S.A
Document Number 30161
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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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
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........ 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
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1699
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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
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