HP HP-97 - Page 104

Component-Level Maintenance
HP-97
Table 4-13. Logic PCA Troubleshooting Procedure (Continued)
STEP ACTION
Replace one at a time ROM 0,
ROM 1, and ROM 3, until the
calculator shows the proper
display.
10.
Replace remaining ICs until
the printer operates satis-
factorily.
1.
Check for open or shorted traces.
12.
Check CR6 and CRT.
13-
Replace ICs until VGG is between
-11.0 and -13.0 Vdc.
14,
Check capacitors C1 and C2 and
diodes CR6 and CRT.
15.
Check waveforms at anodes of
CR5 and CR6. (See figure 4-U4.)
If the display does not show
0.00, check for shorted or
open traces and/or defective
discrete components, and
repair as required.
If the display shows 0.00
and the printer prints 0.00,
return to step 1 and repeat
the test.
If the printer does not print
0.00, replace the PIK. If
the printer still does not
print 0.00, check for shorted
or open traces and/or defect-
ive discrete components and
repair as required.
Return to step 1 and repeat
the entire test.
Return to step 6.
step 6. Return to
Return to step 6.
step 6. Return to
If waveforms are not satisfactory,
check Q2. Then return to step 6.
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