I have a Samsung un58tu7000fxza that powers on (no image, only backlight) but keeps restarting. When it starts up, the backlights seem to be full brightness for 1 sec., off for 1 sec., on again with much lower brightness for 4 sec., full brightness 1 sec., off 6 sec., then repeats. I noticed when the backlights are off, I don’t see the red optical audio port lit, meaning the main board is power cycling. The T-Con must be integrated in this model, because there’s not a separate board. There’s a power board, main board, and driver boards (if that’s what these are called) that are connected directly to the screen ribbon cables down across the bottom. On my main board, there is only one ribbon cable that feeds these driver boards. If I disconnect it, the the TV stays on with backlights at full brightness. I read these models often suffer from bad screens. I did the tape trick to block off some pins in the ribbon and also was able to get the TV to stay powered up without restarting and even heard the start up audio, as well as audio when I used the remote to select menu, etc..). I never could get an image up, but only different line patterns of different colors depending on what pins I had masked off with the tape. I’m trying to isolate the issue to to determine if I have a faulty main board or bad panel. Sounds more like a panel issue since the main board stays powered on with the ribbon disconnected going to the driver boards, but the tape trick never made anything appear on the screen (startup logo, menu text, etc..). Any ideas or suggestions on where to go from here?
Here are the voltage measurements.
TV on with ribbon cable from main board disconnected:
1-GND (0)
3-A13V (12.93 VDC)
5-A13V (12.93)
7-A13V (12.93)
9-A13V (12.93)
11-GND (0)
2-ANA-DIM (3.36 VDC)
4- N.C (0)
6- BLU_PWM (2.88)
8- POWER ON/OFF (3.30)
10- GND (0)
12- GND (0)
Main board disconnected - nothing connected except LEDs (connector snaps directly into power board when installed)
1-GND (0)
3-A13V (12.93 VDC)
5-A13V (12.93)
7-A13V (12.93)
9-A13V (12.93)
11-GND (0)
2-ANA-DIM (3.13 VDC)
4- N.C (0)
6- BLU_PWM (3.30)
8- POWER ON/OFF (4.54)
10- GND (0)
12- GND (0)
Here are the voltage measurements.
TV on with ribbon cable from main board disconnected:
1-GND (0)
3-A13V (12.93 VDC)
5-A13V (12.93)
7-A13V (12.93)
9-A13V (12.93)
11-GND (0)
2-ANA-DIM (3.36 VDC)
4- N.C (0)
6- BLU_PWM (2.88)
8- POWER ON/OFF (3.30)
10- GND (0)
12- GND (0)
Main board disconnected - nothing connected except LEDs (connector snaps directly into power board when installed)
1-GND (0)
3-A13V (12.93 VDC)
5-A13V (12.93)
7-A13V (12.93)
9-A13V (12.93)
11-GND (0)
2-ANA-DIM (3.13 VDC)
4- N.C (0)
6- BLU_PWM (3.30)
8- POWER ON/OFF (4.54)
10- GND (0)
12- GND (0)
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