Model 1713 Extender - Keithley 171 Instruction Manual

MAINTEN'WCE
5-4. ADJ"STMENT AND CALIBlbuION. use the follow-
ing procedure to verify proper operation of the
instrument every 90 days. If rhe instrunent is 0°C
of specification at any point, perform the calibra-
tion procedure specified in the exact order speci-
fied. Recommended teet equipment for calibrating
the Model 171 are given in 'Table 5-7. Calibraxion
equipment other than that listed may be substituted
if the specifications in Table 5-7 are equalled or
exceeded.
These specifications are the minimum re-
quirements for calibrating the 171.
MOOEL 171
C. General Instructions before Calibration.
1. Calibration should be performed in a con-
trolled environment of 25 il'C and relative
humidity below 50%.
2.
me Model 171 should i,ave one (1) hour
warm-up.
3. "se the special calibration top cover pro-
vided with the Model 1713 Extender Card Kit (J).
Unless otherwise indicated, Access Covers A,B,
and C (see Figure 20) should be closed. The PC-
board extender cards provide in the Model 1713
are not required for calibration but are used in
troubleshooting and repair.
a. Preliminary setup.
1. Set the rear panel line switch for either
117" or 234" depending on the line voltage avail-
able.
2.
Check the fuse on
the
rear penel for proper
rating.
117":
112.4 SLO-BLO, 3AG, Keitbley F"-4
234V: 1/4A SLO-BLO, 3AC, Keithley FU-38
3. Connect the power cord to a variable trane-
former which has been set to 117V il" or 234V
+2" depending on the line voltage available.
4. Connecr the shorting link on the front
panel between LO and CASE. For maximum operator
safety, make certain that the chassis is coonect-
ed to earth ground by way of rbe third-conductor
on the line cord or by way of a separate clip
leaI from CASE to earth ground.
5. Set the Power switch to "ON".
b.
Power Supply Check/Calibration. Remove the
top cover of the 171. Make all meaeuremenre with
Digital Voltmeter (K).
1. i5 Volt supply. MeaLwIre the L5" supply
between t5" (TP-14, set Figure 21) oo the in-
tegrator board (R-301) and input LO. If a
reading of +5" i250m" is not obtained, proceed
with troubleshooting and repair.
2. +15 Volt Supply. Measure the +15" supply
between +15V ('P-2, see Figure 21) on 'the in-
tegrator board (PC-301) and input LO, The
Digital Voltmeter (K) should read +15" ?lOm".
If necessary, xl,usr p"te"Ciometer R708 (see
Figure 21) on the mother board (PC-305).
3. -15 Volt Supply. Measure the -15" supply
between -15" (TP-8, eee Figure 21) on the inte-
grator board (PC-301) and input LO. The DVM
should read -15" i&V. If necessary, adjust
potentiometer R711 (see Figure 21) oo the mother
board @C-305).
4. +210 'iolt Supply. Measure the +210" supply
between +ZlOV (acroee R702 on the mother board
K-305; see Figure 21) sod input LO. If a read-
ing of +200 to f240 volts is not obtained, pro-
ceed with troubleshooting and repair.
26
4. Perform all operations only in the order
specified.
5. DO not move the 171 while calibration is
being performed.
6. Unless otherwise indicated, reference all
measorewents to rhe input I.0 terminal of the 171.
7. Unless an input source is specified, the
input HI of the 171 should be shorted to the
input LO with a pure-capper shorting plug (to
minimize thermals; see ParaSraph 2-lal).
d. DC Voltage Mode. Select the dc voltage func-
tion by depressing ehe front panel pushbutton 5903.
Set RANGE switch S902 as required.
1. Zero Adjustmenfs.
a). Driven Guard.
1). Slide Access Cover B (see Figure 20)
co the extreme right position.
2).
set the 171 RANGE switch to 100 rn"
full scale.
3). "sing Null Detector (C) on the 10011"
full scale range, differentially monitor be-
eween P-15 and TP-16 (see Figures 20 and 21)
for a null reading of 0.0 ~20u"dc. Adjust
R527 (see Figures 20 end 21) if necessary.
b).
DC Balance end Analog Amplifier Offset.
1).
Slide Access Cover B (see Figure 20)
co the middle position.
2). Set the 171 RANGE switch to 1" full
scale.
3). "sing Null Defector (C) on the 10~"
full-scale range, monitor the analog OUtpUt
(5502) of the 171 for 0.0 +5u"dc. If necess-
ary, adjust R526 (See Figures 20 and 21).
4). Set the 171 RANGE switch to 10" full
scale.
5).
"sing Null Detector (C) on the 1OU"
full-scale range, monitor the analog outpur
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