Service manual

SERVICE MANUAL MASTER FILE
ENGLISH
Rev. A (1997/05/07)
3-13
.4 UNIT REPAIRING OF THE MAIN BOARD
This section is necessary only for servicers who repair to the component level. Servicers who
perform only board replacement can ignore this section.
The table below lets you troubleshoot problems with the main board (C229MAIN). The table
provides various symptoms, likely cases, and checkpoints. Checkpoints include waveforms,
resistance, and other value to be checked to evaluate the operation of each component.
Table 3-8. Repair of the C229MAIN
Symptom
Condition Cause Checkpoint Solution
The printer
dose not
operate at
all.
The CPU
dose not
operate.
The reset
circuit is not
operational.
Verify the voltage waveforms for the
+5VDC line (IC1, pin 3) and for the
reset signal (IC1, pin 1) when the
power is on.
5V line
/RESET
Figure 3-15. Reset Signal
Replace the
C229MAIN
board.
Selection
control ROM
is abnormal
Verify the signal at pin 22, IC7 or pin
30, IC6 which changes between
HIGH and LOW.
Figure 3-16. Chip Select Signal for
Program ROM
Replace the
C229MAIN
board.