Epson DFX-8500 Service Manual page 191

Table 5-6. C204 MAIN/DRV/DRV-B boards Component Repair 2/7
Symptom
The printer does The control ROM is
not operate at all. defective.
The gate array (IC1)
is defective.
The CPU (IC2) is
defective
The DRAM (IC14) is
defective
Rev. B
Cause
Confirm that the PROM is inserted the
socket correctly.
Check pin 86 (D0)of IC1 for a change
in the signal (HIGH or LOW).
Look at the oscillator at either pin 27
(x1) or pin 28 of the CPU.
Observe pin 2 (D0) of IC14 for a
change in the signal (HIGH or LOW).
Checkpoint
TROUBLESHOOTING
Solution
Replace IC5.
Replace IC1.
Replace CRU1 or
IC1
Replace IC14.
5-17