Read Sharp LC-20M4E (serv.man8) Service Manual online
LC-20M4E
12
TROUBLE SHOOTING TABLE
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Check all the settings microprocessor's adjust process menu.
Do F701 function?
Are T701's secondary
outputs, +34V, +15V, +10V,
+5V and -9V normal?
Remove F701 and
check the load side.
Is there short-circuiting?
Is there short-circuiting of
T701 primary side periphery,
Q701, Q703 and S4001?
Replace F701.
Check S4001 and
connection cable.
Is T701's primary oscillator
waveform normal?
Check T701's secondary
load.
Yes
No
No
No
No
Yes
Fluorecent lamp failure to light up
Does F4701 and F4702
function?
Is the pin (34) of IC1201 in
the "H" state?
Is the Q1774 short-circuiting?
Is there short-circuiting of
T1701~T1706 primary side
periphery, Q1701~Q1705?
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 Q1774 and its
peripheral parts.
Check T1701~T1706,
Q1701~Q1705 and
connection cable.
No
Replace F4701 and F4702.
Yes
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