EPSON FX-2180 Service Manual Chapter 3 Troubleshooting
3-9
3.5 Repairing the Main Board Assembly
The table below provides instructions on how to repair the main board
assembly. It lists various main board problems and provides likely causes,
checkpoints, and solutions. To determine whether a component is
defective, compare its readings with the correct waveforms, resistances,
and other values listed in the table below. Then replace the component if
necessary.
Note:
Use an oscilloscope to check the waveforms in Table 3-7.
Table 3-7. Repairing the Main Board Assembly
Problem Cause Checkpoint Solution
The printer
does not
operate at all.
Reset IC
IC15 is
defective.
Check the voltage waveforms of
the VCC signal (CH 1: pin 7 of
IC15) and the /RESET signal
(CH 2: pin 5 of IC15) when the
printer is turned on.
CH 1
CH 2
Figure 3-12. Waveform 5
Replace the
main board or
IC15.
Table 3-7. Repairing the Main Board Assembly (Continued)
Problem Cause Checkpoint Solution
The printer
does not
operate at
all.
The PROM
(IC5) is not
selected.
Check for a change in the
signal (HIGH to LOW or LOW
to HIGH) at pin 137 of IC1.
Figure 3-13. Waveform 6
Replace the
main board.
The PSRAM
(IC3) is not
selected.
Check for a change in the
signal (HIGH to LOW or LOW
to HIGH) at pin 132 of IC1.
Replace the
main board.
The CPU
(IC2) is
defective.
Check the oscillator signal at
pin 26 or 27 of the CPU.
Figure 3-14. Waveform 7
Replace the
main board.
