Epson LQ-510 - Chapter 7: Troubleshooting

TROUBLESHOOTING
Table 5-5. SANPS(E) Power Board Unit Repair (Cont.)
REV.-A
Problem
Symptom Cause
Checkpoint
Solution
Printer does The voltage
The + 24 V Check the + 24 V line.
not operate at +5 V line line is dead.
at all.
is dead.
IC20 is
Check the oscillation waveform and the switching
Replace
dead. waveform.
IC20.
Switching waveform (IC20, pin 8)
Q20 or Q21
Check the switching waveform.
Replace
is dead. either Q20
or Q21.
Q20, collector
5-12
LQ-510