Found this at the road side. As per the many threads regarding this power supply I replaced the bad fuse FM802S and bad MOSFETS QI820 and QI821. Hooked up the dim bulb tester with up to 425W of bulbs. The set has standby light. When turned on the startup chime plays then the LCD lights flash on and off continually as do the tester lights. The screen shows static and a weak signal message as it is on whatever it was when I picked it up.
The capacitors across the replaced MOSFETS C1890 & C1891 show OL measuring their resistance when removed from board.
Capacitor C1892 shows 456nF when removed from board.
Main caps CP815 & CP816 show 162V with set off and 390V when turned on but fluctuates slightly down to 300V and back.
CNM802 voltages when on and lights flashing
PWR - ON/OFF 1.169
STBY5.3V 5.15
GND
GND
5.3V 5.13
5.3V 5.13
GND
13V 12.77
13V 12.77
INV_ON/OFF 4.7
E-PWM 4.23
DET_5V 0-3.7-4.78 It stays at 4.78 for a moment the cycles through the voltages always staying on 4.78 for a moment
None of the voltages change as if they are reacting in time with the flashing of the lights.
Disconnecting the cable between the PSU/Inverter and the mainboard and plugging the TV in the light flashing begins without pressing the power button.
Disconnecting the cable from the main board to the TCON has no effect on the situation.
Disconnecting the FPCs from the TCON to the panel has no effect.
The last attached file, LN40B500P3F.pdf is actually a video of the problem. As video is not a valid upload type you will have to download it and change its file extension to mp4 before you can play it.
I don't know where to go from here. I have a feeling that using the dim bulb tester even with up to 425W of lightbulbs it is causing the issue but I am hesitant to try the set with out the dim bulb tester so as not to ruin what I just put in. So before I did anything foolish I thought I should check with the experts.
What should I check next? Have you ever experienced this behavior?
Your help is most appreciated. Thank You
The capacitors across the replaced MOSFETS C1890 & C1891 show OL measuring their resistance when removed from board.
Capacitor C1892 shows 456nF when removed from board.
Main caps CP815 & CP816 show 162V with set off and 390V when turned on but fluctuates slightly down to 300V and back.
CNM802 voltages when on and lights flashing
PWR - ON/OFF 1.169
STBY5.3V 5.15
GND
GND
5.3V 5.13
5.3V 5.13
GND
13V 12.77
13V 12.77
INV_ON/OFF 4.7
E-PWM 4.23
DET_5V 0-3.7-4.78 It stays at 4.78 for a moment the cycles through the voltages always staying on 4.78 for a moment
None of the voltages change as if they are reacting in time with the flashing of the lights.
Disconnecting the cable between the PSU/Inverter and the mainboard and plugging the TV in the light flashing begins without pressing the power button.
Disconnecting the cable from the main board to the TCON has no effect on the situation.
Disconnecting the FPCs from the TCON to the panel has no effect.
The last attached file, LN40B500P3F.pdf is actually a video of the problem. As video is not a valid upload type you will have to download it and change its file extension to mp4 before you can play it.
I don't know where to go from here. I have a feeling that using the dim bulb tester even with up to 425W of lightbulbs it is causing the issue but I am hesitant to try the set with out the dim bulb tester so as not to ruin what I just put in. So before I did anything foolish I thought I should check with the experts.
What should I check next? Have you ever experienced this behavior?
Your help is most appreciated. Thank You
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