Troubleshooting - Sylvania 6842THG Service Manual

1. POWER SUPPLY SECTION
Problem
The voltage of both ends on C2115 is 0V or lower than
170V.
F601 is cut off.
R2001 and R2004 are cut off, or smoke.
1. Malfunction
F2200 is cut off.
occurs in stand-
F2400 is cut off.
by mode.
5V is not outputted to VSUB 5V.
[After oscillating, oscillating stops. (Overvoltage
latching)]
Stand-by consumption power is too high.
(Not oscillating intermittently. Abnormal oscillating.)
RY2000 does not turn on.
(DC16V is not outputted.)
2. Cannot power
on.
PFC does not oscillate.
(The voltage of both ends on C2115 does not reach for
approximately 385V.)
Protect 1
functions.
3. The power turns
off immediately
after turning the
power on.
(D2506 blinks.)
Protect 2
functions.
ADD-
MONITOR
function.
SUS-
MONITOR
function.
4. Vdata is poor. The waveform of T2300 stops oscillating or abnormal.
5. Vsus is poor. The waveform of T2200 stops oscillating or abnormal.

TROUBLESHOOTING

Details of Condition
If removing D2503, the unit turns the
power on normally. (5V line is poor.)
If removing D2505, the unit turns the
power on normally. (15V line is poor.)
If removing D2510, the unit turns the
power on normally. (3.3V line is poor.)
If removing D2504, the unit turns the
power on normally. (VE line is poor.)
If removing D2500, the unit turns the
power on normally. (Vset line is poor.)
If removing D2501, the unit turns the
power on normally. (Vscan line is poor.)
If R2537 is shorted, the unit turns the
power on normally.
ADD-MONITOR (IC2500 : 32pin) voltage
is lower than 3.5V.
SUS-MONITOR (IC2500 : 31pin) voltage
is over 2.5±1V.
Checking Parts (Ref. No.)
F601
IC2100, IC2200, IC2300, IC2400
Q2101, Q2102, Q2600
D2101, D2106, D2153
R2105
IC2200
IC2400
IC2403, IC2450
F2400
D2400, D2401, D2405, D2407, D2452, D2456, D2463
IC2401
Q2400, Q2401, Q2402,Q2403, Q2404
D2411
IC2401
Q2400, Q2401, Q2402
D2403, D2404, D2414, D2416
IC2100, IC2101
Q2100, Q2103, Q2104, Q2105, Q2106, Q2108
D2103, D2105, D2109, D2110
Q2451, Q2452
IC2451
D2452, D2454
IC2454
Q2453, Q2454
D2452, D2455, D2460
Q2850, Q2851, Q2852, Q2853, Q2854, Q2855
D2850, IC2853
Q2600, Q2601, Q2602, Q2750, Q2751, Q2752, Q2753, Q2754,
Q2755
IC2600, IC2601, IC2754, D2600, D2602, D2603, D2750, D2751
Q2600, Q2601, Q2602, Q2650, Q2651, Q2652, Q2653
IC2600, IC2601, IC2651, D2600, D2602, D2603, D2750, D2751
Refer to " 2. Cannot power on" section.
Refer to "4. Vdata is poor" section.
Refer to "5. Vsus is poor" section.
Q2300, Q2301, Q2302
D2300, D2302, D2304, D2353
IC2300, IC2301, IC2350
IC2201
Q2201
D2202, D2204, D2205, D2211, D2212, D2213, D2214, D2215
1-8-1 L0700TR