Sharp LC-121M2E Service Manual page 23

7. TROUBLE SHOOTING
No picture, No sound
NO
Fluorecent lamp failure to light up.
LC-121M2E
LC-150M2E
Do F701 and F703 function?
YES
Are T701's secondary outputs,
+30V, +23V, +9V, +5.1V and
-§.5V normal?
Remove F701 and F703, and | NO
check the load side.
ts there short-circuiting?
| Does F702 function?
| YES
appear?
Is T701's primary oscillator NO
waveform normal?
YES
Check T701's secondary load.
Check IC702, Q702, L701
and their peripheral parts.
Is there short-circuiting of T701
primary side periphery, Q701
and S701?
Replace F701 and F703.
YES
Does Q703 function?
Does output voltage +9V
Is primary oscillator waveform NO
of T751 and T752 normal ?
YES
Replace the fiuorecent lamp
with new one and check again.
bid Check Q703 and its peripheral
parts.
Check Q751, Q752, Q753,
Q754, T751, 1752 and their
peripheral parts.
No picture (AV1, AV2 and Component)
Is output voltages [NO | Check IC406 and
at pins 3,5 and 6 of | its peripheral parts.
IC406 normal? ——————
YES
Is input voltages at |NO | Check peripheral
pins 51,52 and 53
parts. oe
of IC801 normal?
YES
Is output voltages at] NO
pins 41,42 and 43
of 1C801 normal?
YES
ls output voltages |NO | Check IC803 and
at pins 1,7 and 8 of |" its peripheral parts.
1C803 normal? Se
YES
Check IC801 and
its peripheral parts.
Is in/output voltages of IC 1001 normal?
YES
No picture
No picture (AV1, AV2)
ls in/output voltages; NO {Check 1C401 and
lof (C401 normal? its peripheral parts.
YES
Is output voltages | NO
at pins 23 and 25
of 1C851 normal?
Are output voltages} NO
at pin 7 of IC403 and
it of IC405 normal?
YES
Is input voltages
at pins 13 and 15
of IC801 normal?
YES
ls output voltages
Check IC851,
Q852, 0854, Q857
and their peripheral
parts.
Check IC-403,
IC-405 and their
npheral parts.
Check Q801, Q802
and their peripheral
rts.
Check IC801 and
at pins 4,5 and 6
of IC801 normal?
YES
its peripheral parts.
Is in/output voltages of IC1201 normal?
YES
Check in/output voltages of IC406
and its peripheral parts.
Are voltages and waveform of the LCD module connecting connector normal?
YES
Aren't cables break down?
YES
NO
Replace cables with new one and check again.
Replace LCD module with new one and check again.
23
No picture apears (AV1)
Check Q401~Q406 and
their peripheral parts.
No picture (AV1/AV2) | |No picture (Component)
Is signal input into the pin | NO
13 of 1C2001?
YES YES
Check IC401 and
its peripheral parts.
| Is output voltage at pin 18 of IC801 normal?
Check the in/output
of IC406 and its
peripheral parts.
NO
Is input voltages at pins 33 and 15 of
IC801 normal?
Check IC406, 1C403 and their peripheral
F I A ee Ee E S T E aN