Epson FX-2170 Service Manual page 132

FX-2170 Service Manual
Table 5-6. Repairing the C166 PSB/PSE Board Assembly (Continued)
Problem
The 35 V and Q32 is dead.
5 V lines are
not output
when the
printer is
powered on.
Q31 is dead.
^
The +5 V line
IC51 is dead.
is not output.
Q51 is dead.
^
L51 is short.
^
The PWDN IC52 is dead.
signal is
constantly
HIGH.
Rev.A
Cause
Check that the resistance between the
collector and emitter is infinite.
Check that the resistance between the
source and drain is infinite.
Check the voltage waveform at pin 8 of
IC51. The voltage waveform is as follows:
Check the voltage at pin 12 of IC51.
Check the voltage waveform between
emitter and collector of Q51.
Check the resistance between both
terminals of L51
Check whether the voltage of pin 6 is
more than 1.3 V or not. If the voltage is
more than 1.3 V, IC52 is dead.
Troubleshooting
Checkpoint Solution
Replace
the Q32.
Replace
the Q31.
Replace
IC51.
Replace
Q51.
Replace
L51.
Replace
IC52.
5-11