Service manual

30
LC-20VM2
LC-121M2E
LC-150M2E
8. TROUBLE SHOOTING
No picture, No sound
Do F702 and F703 function?
Check T701's secondary load.
Check IC702, Q702, L701
and their peripheral parts.
Remove F702 and F703, and
check the load side.
Is there short-circuiting?
Is there short-circuiting of T701
primary side periphery, Q704
and S4701?
Replace F702 and F703.
YES
NO
YES
YES
YES
NO
NO
Check Q7751~Q7755,
T7751~T7756 and their
peripheral parts.
Check IC1201, IC1206, IC2001
and their peripheral parts.
Replace the fluorecent lamp
with new one and check again.
Is primary oscillator waveform
of T7751~T7756 normal ?
Is the pin 11 of IC1201 in the
"H" state?
Does F7751 function?
Replace F7751.
Fluorecent lamp failure to light up.
YES
YES
YES
NO
NO
NO
NO
Is T701's primary oscillator
waveform normal?
Are T701's secondary outputs,
+30V, +9V, +5.0V and -8V
normal?
Check IC406, IC402 and their peripheral parts.
No picture (AV1, AV2 and Component)
Is output voltages
at pins 3, 5 and 6
of IC406 normal?
Is input voltages at
pins 51, 52 and 53
of IC801 normal?
Is output voltages at
pins 41, 42 and 43
of IC801 normal?
Is output voltages
at pins 1 of IC315
and 1, 7 of IC316
normal?
No picture (AV1, AV2)
Replace LCD module with new one and check again.
Replace cables with new one and check again.
No picture
Check the in/output
of IC406, IC451
and its peripheral
parts.
No picture (AV1/AV2)
No picture (Component)
Is signal input into the pin
13 of IC2001?
Check IC406 and
its peripheral parts.
Check IC801 and
its peripheral parts.
Check IC315,
IC316 and its
peripheral parts.
Is in/output voltages of IC1001 normal?
Is in/output voltages of IC1201 normal?
Are voltages and waveform of the LCD module connecting connector normal?
Aren't cables break down?
Is in/output voltages
of IC401 normal?
Check IC401 and
its peripheral parts.
Is output voltage at pin 18 of IC801 normal?
Is input voltages at pins 33 and 15 of
IC801 normal?
Check IC401 and
its peripheral parts.
Is output voltages
at pins 23 and 25
of IC853 normal?
(When inputting
except NTSC)
Check IC853,
Q852, Q854, Q857
and their peripheral
parts.
Check IC402,
IC407 and their
peripheral parts.
Check IC801 and
its peripheral parts.
Are output voltages
at pin 6 of IC402 and
it of IC407 normal?
Check Q802, Q803,
Q805, Q806 and
their peripheral parts.
Is input voltages
at pins 13 and 15
of IC801 normal?
Is output voltages
at pins 4, 5 and 6
of IC801 normal?
Check in/output voltages of IC406, IC451
and its peripheral parts.
NO
No picture apears (AV1)
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Check Q407~Q410 and
their peripheral parts.
Check peripheral
parts.
YES YES
NO
NO
YES
Is output voltages
at pins 83 and 84
of IC7001 normal?
(When inputting
NTSC)
Check IC7001,
IC7002 and their
peripheral parts.
NO
YES
YES
YES
YES
YES