Repair Of The C117 Main Board Assembly - Epson C117001-N - DFX 5000+ B/W Dot-matrix Printer Service Manual

5.4 REPAIR OF THE C117 MAIN BOARD ASSEMBLY

This section provides detailed troubleshooting methods to isolate components in the C117 MAIN
board. This information is for use by servicers who repair to the component level. U.S. servicers
repair to the unit leveI only, and may ignore this section.
The table below provides instructions to repair the C117 MAIN board assembly. It describes
various symptoms, likely causes, troubleshooting checkpoints, and solutions. The checkpoints
column describes proper waveforms, resistance values, and other values to check when evaluating
the operation of a component that may be defective. Check these values and repair the board as
described in the solution column.
Table 5-6. CI17 MAIN Board Assembly Component Repair
Symptom
The DRERR signal
The printer
was sent to the Cl 17
does not
operate at all.
(a HIGH level turns
off the power supply).
The VPC signal
(HIGH level) was not
sent to the Cl 17
power supply board.
(If VPC is output to
the power supply,
and the head driver is
not
defective, the
gate array is probably
defective.)
The reset circuit is
not operational (for
logic).
Rev. A
-
Cause
Measure the voltage level of the
head driver IC'S voltage waveform.
Check the voltage waveform for the
signal
and verify the voltage waveform for the
head driver. (Refer to the head driver
waveform figure, above.)
.
2V
Look at the voltage waveform
+5 V line (pin 3 of IC9) and the reset
signal (pin 1 of IC9).
—
Checkpoint
when power is turned on
A r -000s
I
for the
SAVE
PE
Troubleshooting
,
Solution
Replace the
head driver.
Replace the
head driver
or gate array.
Replace IC9.
5-17