Service manual

20
LC-20B4M
TROUBLE SHOOTING TABLE (Continued)
Do F3701 and F3702
function?
Check all the settings on the microprocessor
’s adjust process menu.
Are secondary outputs
(+38V, +9V, +5V, -11V) of
T3701 as specified?
Are the oscillation waveform
at T3701’s primary side as
specified?
Disconnect F3701 and
F3702. Is the load side
short-circuited?
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.
Do F6700, F6701,
F6702, F6703, and
F6704 function?
Is Pin (120) of IC1201 at
“H”?
Are the oscillation waveforms
at the primary side of T6700,
T6702, T6704, T6706, and
T6708 as specified?
Replace F6700, F6701,
F6702, F6703, and F6704.
Check the line, IC1201 and
its peripheral parts.
Check Q6700 - 6714, T6700
- 6709 and their peripheral
parts.
Replace the fluorescent lamp
and check the oscillation
waveform again.
Is input at Pin (72) of IC801
as specified?
Check SC3405, SC line and
peripheral parts.
Check all the settings on the microprocessor
’s adjust process menu.
Is input at Pins (1) and (3) of
IC801 as specified?
Check J3404, PB line, PR line
and peripheral parts.
No picture and sound
Yes
No
No
Yes
Yes
No
Yes
No
Fluorescent lamp failure
Yes
No
Yes
No
Yes
No
Yes
Yes
No colour
No TV colour No S-VIDEO colourNo VIDEO colour No COMPONENT colour
No No