HP HP-97 - Page 107

HP-97 Component-Level Maintenance
Table 4-14. Printer PCA Troubleshooting Procedure (Continued)
STEP ACTION
6.
Turn the calculator off. If the motor resistance is
Measure the resistance 10+-1 ohms, go to step 7.
across the motor.
If not, replace U2. Then go
to step 7.
Turn the calculator on.
Measure the reference
voltage at U5, pin 1. If the reference voltage is
-1+-0.025 Vdec, go to step 9.
If not, replace U4 and/or U5.
Then go to step 8
8.
Press the paper advance
switch. If the paper advances go to
step 9.
If not, go to step 11.
9.
Check pin 17 of the board If the signal of 1.5 milli-
for the FWD signal. second duration is present,
replace in order Q14, U1, Q13,
R1, R2. Then go to step 11.
If not, replace U5 and U4 in
order until the 1.5 milli-
second signal appears. Then
go to step 10.
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