Sharp LC 20M4U, Руководство по обслуживанию

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13
LC-20M4U
TROUBLE SHOOTING TABLE
No picture, No sound
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