Repair Of C124 Psb/Pse Board - Epson DLQ-3000+ Service Manual

5.3 Repair of C124 PSB/PSE Board

This section describes how to repair the PSB/PSE board to the component. Table 5-8 shows the
abnormal conditions and corresponding causes, check points and solutions. Select the condition
from the table and perform any necessary check and repair.
Condition



Symptom : Normal voltage is not output.
Fuse is blown Line filter circuit
out soon after is defective.
replaced.
Rectification or
smoothing
circuit is
defective.
All output Diode bridge

voltages are
abnormal. defective.
(Due to the
circuit structure,
when the +35 V
output is Soft start circuit
abnormal, all (surge circuit) is
other output defective.
voltages are
affected.)
Switching FET

defective.
Notes:


1. is possibly shortened as a result of the short circuit of other components behind
2. Degradation of some component behind
Rev. A
Table 5-8. C124 PSB/PSE Board Repair
Cause
Check
with the AC line.
Check the followings for short circuit:



All (+) terminals between



and
(See Note 1.)
Check that the voltage output from pin
3 (+) and pin 4 (-) on DB101 is as
is
follows:

 




(See Note 2.)

Check that DC voltages at the both
ends of R2 and R3 are 0 V.

R2 and R3 are open,
or R124, D103, or
are used to turn on
Check for the correct switching

or is operation of
the waveform output from pins 6 and
7 of the T101/201 primary coil is
correct, as shown below.
Figure 5-9. Switching Waveform


Check point



to or L4 for a short circuit



: Approximately 170V
: Approximately 300V

 
/

 
/ by checking if
may suppress the
Troubleshooting
Solution
Replace any
defective
component.
Replace the


or any
and
associated
defective
component.
Replace the


or any
associated
defective
component.
Replace
board or
any associated
is bad,
defective
which
component.
is bad.
Replace the

/

or any
associated
defective
component.


output voltage
board,
board,

board,


.
5-11