Service manual

40
LC-15B4U-S
LC-15B4U-B
TROUBLE SHOOTING TABLE (Continued)
No picture and sound
Yes
No
Do F3701and F3702
function?
Check all the settings on the microprocessor
’s adjust process menu.
No
Are secondary outputs
(+38V, +9V, +5V, -11V) of
T3701 as specified?
Yes
Are the oscillation waveform
at T3701’s primary side as
specified?
Yes
No
Disconnect F3701 and
F3702. Is the load side
short-circuited?
Yes
No
Is any of T3701
’s primary
side, Q3703 and S4701 short-
circuited?
Check J3701, its peripheral
parts and connection cable.
Replace F3701 and F3702.
Check S4701 and
connection cable.
Check the secondary-side
load of T3701.
Fluorescent lamp
failure
Yes
No
Does F6500 and F6702
function?
Yes
No
Is Pin (120) of IC1201 at
“H”?
Yes
No
Are the oscillation waveforms
at the primary side of T6500
and T6501 as specified?
Yes
Replace F6500
Yes
Check the line, IC1201 and
its peripheral parts.
Yes
Yes
No
Is Pin (3) of P6502 at
“L”?
Check Q3601
Check Q6500 - 6505 and
their peripheral parts.
Replace the fluorescent lamp
and check the oscillation
waveform again.