Samsung UN55KS8000fxza turns on then off repeatedly

[nwelec]

TV turns on then almost immediately shuts off and does this for as long as it is plugged in. I did remove power to the main board and the tv stays on. I put what I thought was a good replacement main board in and the same problem. I am now wondering if I am dealing with a bad panel.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

thought I would add the voltages I get when the panel lights up at CNL801

1 thru 4, 18 thru 20 and 27 are gnd
7, 9 and 11 vamp 13v
13, 15, & 17 13v reads 13v
21, 23, 25 & 29 pwm 1.3v
8 od_LEV 3.34v
10 Fail_ct 3.34
12 OD_o/f 3.3v
14 blu_o/f 4.1v
16 Power_o/f 3.34v
22, 24, 26 & 28 PWM 2.25
30. ana_dim 2.5v
I hope this helps some. The voltages do drop to 0 or almost 0 when the tv restarts.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Finally figured out it is a bad panel. I got one in with a cracked panel and it does the same thing. Hope this helps someone out there.

[nomoresonys]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Check the components on your driver board, might get lucky.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

OK, Thanks.

[nomoresonys]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

To clarify, the driver board is the board attached to the screen, some call it tab bond board it usually is not easy to get at without a little disassembly.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Thanks and yes I knew that.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Think I finally found the problem. I took nomoresonys advice and checked the driver board and found one of the flat ribbon cables that is between the right side driver boards was crimped. If I remove it the picture no longer flashes and if I put it back but not quite in straight I get a scrambled picture. Now I just need to find a undamaged flat ribbon cable to test my theory

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Spoke too soon. I found what looks like two burnt resistors on the far right board. Any know how I can find replacements?

[diif]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Spoke too soon. I found what looks like two burnt resistors on the far right board. Any know how I can find replacements?

Check the far left board as they are usually symmetrical. The values are written on them.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

I did and it is not configured the exact same way so I found 4 resistors on it but different values.

[nwelec]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Update to this problem in hopes it will help someone else. Removed the two bad resistors on the far right (looking at the back) driver board (again thanks to nomoresonys) and now the tv works fine.

[morinb]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Update to this problem in hopes it will help someone else. Removed the two bad resistors on the far right (looking at the back) driver board (again thanks to nomoresonys) and now the tv works fine.

Thanks so much for posting this. I have a UN55KS8500FXZA that's having the same problem you had. I replaced the mainboard and the power board with no luck. After reading your post, I looked at the boards that run along the bottom of the screen (driver boards?) and I found burnt resistors on the far-right board and on the far-left board (link to pictures).

As someone who's only ever done a minimal amount of soldering/desoldering (and even that was well over a decade ago), I was hoping somebody here might have some tips or tool recommendations for removing these resistors. Any help would be appreciated!

And thank you again!

[nomoresonys]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

A little demo there, there's a ton more if needed: https://www.youtube.com/watch?v=8JM4oCpWnjU

[morinb]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

Awesome, thank you, wish me luck

[nomoresonys]

Re: Samsung UN55KS8000fxza turns on then off repeatedly

For sure, let us know how you get on.