Read Sharp LC-20A2E (serv.man2) Service Manual online
LC-20A2E
11
TROUBLE SHOOTING TABLE
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Check all the settings microprocessor's adjust process menu.
Do F2, F3 and F4
function?
Are T701's secondary
outputs, +38V, +16V, +9V,
+5V and -8V normal?
Remove F2, F3 and F4
and check the load side.
Is there short-circuiting?
Is there short-circuiting of
T701 primary side periphery,
Q751, Q753 and S4701.
Replace F2, F3 and F4.
Check S4701 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
T7751~7756 primary side
periphery, Q7751~Q7755.
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 T7751~T7756,
Q7751~Q7755 and
connection cable.
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