HP 5890 SERIES II Service Manual page 263

Keyboard and Display Troubleshooting
Problem
1. No visual indications of any
kind on display.
2. Some portion of the display
is blank. (Bad LED, etc.)
3. No keyboard control of
instrument.
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Probable Cause
a. Faulty display PCB assem-
bly.
b. Faulty display PCB ribbon
cable.
c. Faulty main PCB.
a. Faulty display PCB assem-
bly.
b. Faulty display PCB ribbon
cable.
c. Faulty main PCB.
a. Keyboard locked.
b. Faulty display PCB assem-
bly.
c. Faulty display PCB ribbon
cable.
d. Faulty main PCB.
SVC 8- 2
Corrective Action
1. Replace display PCB as-
sembly.
2. If problem persists, remove
replaced display PCB
3. Install original display PCB
assembly.
4. Go to probable cause b.
1. Replace display PCB rib-
bon cable..
2. If problem persists, go to
probable cause c.
1. Replace main PCB.
1. Shut off instrument and re-
start.
2. All indicators should light
during start- up self test.
Observe suspect portion of
display.
3. If any indicators are out, re-
place display PCB.
4. If problem persists, remove
replaced display PCB
5. Install original display PCB
assembly.
6. Go to probable cause b.
1. Replace display PCB rib-
bon cable..
2. If problem persists, go to
probable cause c.
1. Replace main PCB.
1. Press clear dot minus enter
and set the lock status to
OFF.
2. If problem persists, go to
probable cause b.
1. Replace display PCB as-
sembly.
2. If problem persists, remove
replaced display PCB
3. Install original display PCB
assembly.
4. Go to probable cause c.
1. Replace display PCB rib-
bon cable..
2. If problem persists, go to
probable cause d.
1. Replace main PCB.