Samsung UE46D6200 not turning on

[Fritz23]

Hi guys,

I currently have a Samsung UE46D6200TSXZG which does not turn on. When connecting the power cord the standby LED comes on normally. When pressing the power button the standby LED starts flashing 2x 5 times. After these flashes you can hear the mainboard switching on for a second. When I connected the TV the first time it did flash the backlight for a very short time but since then I didn't see it again.

Modelnumbers:
PSU: BN44-00458A (PSLF151A03D)
Mainboard: BN41_01604C (BN94-05367J)
TCON: V460HK1-C01

The inside of the TV is generally covered in black dust but there are until now no obviously burned components. When disconnecting the mainboard the backlight turns on and stays on. The TV won't try to power up without the TCON at all. If I disconnect the TCON while the TV is powering up it doesn't change anything.

I did some measurements on connector CNM803A.
Everything connected, TV in standby:

1. GND : -
3. B13V: 0.0 V
5. B13V: 0.0 V
7. Vamp: 0.0 V
9. Vamp: 0.0 V
11. GND: -
13. B5V: 0.0 V
15. B5V: 0.0 V

2. OD_ON: 0.0 V
4. PWM_DIM: 0.0 V
6. N.C.: -
8. BLU_on/off: 0.0 V
10. GND: -
12. GND: -
14. A5V: 5.28 V
16. Power on/off: 0.26 V

Everything connected, TV trying to power up:

1. GND : -
3. B13V: 0.0 V / 12.66 V (cycling)
5. B13V: 0.0 V / 12.66 V (cycling)
7. Vamp: 0.0 V / 12.66 V (cycling)
9. Vamp: 0.0 V / 12.66 V (cycling)
11. GND: -
13. B5V: 0.0 V / 5.27 V (cycling)
15. B5V: 0.0 V / 5.27 V (cycling)

2. OD_ON: 0.0 V / 0.54 V (cycling)
4. PWM_DIM: 0.0 V / 1.13 V (cycling)
6. N.C.: -
8. BLU_on/off: 0.0 V / 0.13 V (cycling)
10. GND: -
12. GND: -
14. A5V: 5.28 V
16. Power on/off: 0.26 V / 3.28 V (cycling)

Just backlight connected:

1. GND : -
3. B13V: 12.68 V
5. B13V: 12.68 V
7. Vamp: 12.68 V
9. Vamp: 12.68 V
11. GND: -
13. B5V: 5.28 V
15. B5V: 5.28 V

2. OD_ON: 8.42 V
4. PWM_DIM: 2.82 V
6. N.C.: -
8. BLU_on/off: 2.12 V
10. GND: -
12. GND: -
14. A5V: 5.28 V
16. Power on/off: 3.3 V

Since the voltages are alright and the backlight turns on with nothing connected I think the PSU is alright. I'm pretty sure the fault is in the mainboard. It's my third TV with a similar mainboard and a new mainboard always fixed it.
This time instead of just swapping out the mainboard and expecting the owner to come back in six months just because the same fault appeared again, I'm more interested in trying to find the fault on this mainboard.

Any suggestions on this? Are the caps in the pictures already considered to be bulged or do they look normal? I did try to reset the EEPROM with shorting M_E_SDA and M_NRESET without luck.
The owner told me that the TV did throw the circuit breaker the last time it worked and after he came back the TV showed this behaviour. He's not sure the TV caused this and since the fuses on the PSU are ok I don't worry about that.

I probably forgot something so just ask. I'm open for any suggestions.

[dick_barton]

Re: Samsung UE46D6200 not turning on

With mainboard disconnected, the power supply and backlights appear from your testing to be working so it does indeed look like a mainboard fault.
Sets are just not made to last anymore.

[Fritz23]

Re: Samsung UE46D6200 not turning on

It's even sadder because it appears to be one of the few Tv's of the D-series that doesn't have bonding problems.

[dick_barton]

Re: Samsung UE46D6200 not turning on

Wait and see what others may think.

[Fritz23]

Re: Samsung UE46D6200 not turning on

Ok I ordered a "new" mainboard. The first board that arrived wasn't working at all and the replacement board did work for 10 minutes.
It did freeze every two minutes with the sound starting to loop, the image getting completely destroyed and not reacting to any of the touch buttons at all. After this it restarted and repeated.
After the 10 minutes it went black and now it's just turning the backlight on and off without showing any image at all. The backlight turns on for about 15 seconds and then turns off before the process repeats.
During this the cpu is generating serious heat.

Probably again got a faulty mainboard.

[Andrew F. Ali]

Re: Samsung UE46D6200 not turning on

Yes. You got a faulty Main bd. Return it and ask for an exchange or refund. You definitely have a Main Bd. Issue. Just as a matter of interest, do a continuity test on the SMD fuse on the T-CON Bd.

[Fritz23]

Re: Samsung UE46D6200 not turning on

After everything cooled down again the TV turns on normally until the problems starts again. When I unscrew the mainboard screws a little bit it takes more time until the problems appear. So definitely a heat related problem. Bad solderjoint probably under the cpu.

This matches pretty good with what I found on the old mainboard. After I removed the chips there were plenty of loose solderballs which you could knock over just by looking at them. The caps in the picture are also bulged. Sadly I don't have the equipment to try a reballing.

Already contacted the seller. The T-CON fuse is good.