Read Sharp LC-20B2E (serv.man9) Service Manual online
12
LC-20B2E
TROUBLE SHOOTING TABLE
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Check all the settings microprocessor's adjust process menu.
Do F2 and F4 function?
Are T701's secondary
outputs, +38V, +16V, +9V,
+5V and -8V normal?
Remove F2 and F4 and
check the load side.
Is there short-circuiting?
Is there short-circuiting of
T701 primary side periphery,
Q751, Q753 and P901.
Replace F2 and F4.
Check P901 and
connection cable.
Is T701's primary oscillator
waveform normal?
Check T701's secondary
load.
Yes
Yes
No
No
No
No
Yes
Fluorecent lamp failure to light up
Does F1 function?
Is the pin (34) of IC1201 in
the "H" state?
Is the Q3603 short-circuiting?
Is there short-circuiting of
T5701 and T5702 primary
side periphery, Q751~Q753.
Yes
Yes
No
No
No
Yes
Replace the fluorecent lamp
with new one and check
again.
Yes
Check the OFL1 line, IC1201
and their peripheral parts.
Check Q3603 and their
peripheral parts.
Check T5701, T5702,
Q5701~Q5703 and
connection cable.
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