Unit Repair - C137 Psb/Pse Board - Epson Stylus Pro Service Manual

Stylus Pro Service Manual
5.3 UNIT REPAIR — C137 PSB/PSE BOARD
This section describes problems related to the power supply board (C137 PSB/PSE). The table below
provides various symptoms, likely causes, and checkpoints. The checkpoints are waveforms, resistances, and
other values to be checked to evaluate the operation of each component.
Symptom
Condition
+35 V line is
dead.
+35 V line is
abnormal.
The printer
does not
operate at all.
+5 V line is
dead.
Auto capping
+35 V line is
operation is
invalid when
invalid.
power off.
Rev.A
Table 5-6. Repair of the C137 PSB/PSE
Cause
Transformer (T1)
coils are open.
Switching FET
(Q 1)
ZD52, Q83 or
PC1 is dead.
+35 V line is
dead.
IC51 is dead.
IC81 is dead.
IC82 is dead or
R88 is shorted.
Checkpoint
Check the coils for transformer
using a multimeter.
Check the waveform at the drain of
Q 1 .
Check the voltage level of the
corrector side. Correct voltage is
as follows;
Power Switch OFF = +1.8 VDC
Power Switch On = 0 VDC
Check the +35 V line.
Check the oscillation waveform
and switching waveform of IC51.
Oscillation waveform (IC51, pin 5)
Switching waveform (IC51, pin 8)
Turn off the printer and check the
voltage at pin 1 of IC81.
Normal voltage = 0 VDC
Turn off the printer and check the
voltage at plus side of C82.
Normal voltage = 2.5 VDC
R88 resistance = 100
Troubleshooting
Solution
Replace T1.
Replace Q1.
Replace
ZD52, Q82
or PC1.
Replace
IC51.
Replace
I C81
Replace
C82 or
R88.
5-9