Samsung Plasma TV Power Cycling

RCon

Commendable
Oct 25, 2016
6
0
1,510
0
Hello, I have a Samsung pn51d6500dfxza TV. It power cycles after about 2-5 minutes of being on (a loud click when going on or off).

What I tried/noticed:

-I unplugged everything from the power supply board except for the main and logic control board. Still power cycled (this includes the button control panel, speakers, wifi, etc).

-All ground screws are tight

-I had it on long enough to setup wifi. Then turn it back on and do a quick firmware update (completed successfully).

-All connections were pulled out and reseated.

-All capacitors look fine (I tried testing some with a new multimeter I bought, but I think I need to take it back. None of the caps or any spares I had are giving a reasonable reading). So, without testing each one with a tool, they look ok by eye.

-While on, the standby power is reading 15 (which it said is accurate). However, when in standby mode, it's reading 0 (is this right? Shouldn't standby still be reading something?). The red standby light is working as intended

-The green light in the back flashes once a second (as it should).

I can't shake the feeling that there is a bad cap somewhere... most likely on the power supply board. Does anyone know of a way that I could test each of those three boards separately? If anyone has any suggestions on what to try or what it could be, I'm open to hearing them!

Thank you in advance!
 

RCon

Commendable
Oct 25, 2016
6
0
1,510
0
I jumped the ps-on and ground to start it without the main board. No shorting, no disconnecting. I'm narrowing my focus down to that. None of the chips look burnt/bubbled. All the text on them is visible. The heatsinks are firmly in place. I disconnected the speakers along with the power/volume button panel once again, no change. I also jumped the logic board to make sure that was ok one last time. No change. I'm fairly certain it is the main board. Anyone know how I could go about testing for shorts on it?
 

RCon

Commendable
Oct 25, 2016
6
0
1,510
0
Update: Everything looks fine on the main board. Again, any way to test? A new thought though: Could it be the firmware causing it to crash? I did update... but is there a way to set it back to factory setting? I did think it was weird that it didn't crash the whole time I did the firmware update (I thought I was just lucky).
 

RCon

Commendable
Oct 25, 2016
6
0
1,510
0
Another update: Went into service mode and factory reset it. Still giving me the problem (so I'm thinking it's not a firmware issue). Will even shut off while in service mode.
 

RCon

Commendable
Oct 25, 2016
6
0
1,510
0
Another update: (I should have probably just edited them all into my main question. Sorry.) I used diode mode on my multimeter to test the chips on the main board. One of them is giving me OL. Would that mean that this is bad? Or that there is a short somewhere? It has 4 legs on each side. If we label them 1 thru 4 I only get an OL reading when on pin 2 and 4 of the one side while the ground is on either pin 3 or 4 on the other. (sorry for being too confusing).
 

RCon

Commendable
Oct 25, 2016
6
0
1,510
0

Yes! Sorry. I normally try to follow up on these. I narrowed it down to the main board since it would stay powered on when bypassing the main board. I sent it in to have it repaired (the service was like $80 on ebay). It's been working ever since. I believe it was a bad IC. I tested one and it seemed different than the others. However, I don't work with them much so I wasn't sure if I was even testing it right. I tried to look over the board for new solder after it was sent back (out of curiosity), but nothing stood out.
 

joesparent

Prominent
Jan 4, 2018
2
0
520
1
Thanks! I will see what i can do. Mine continously cycles. It'll turn on and be on for a minute or two and then restat and will remain on for a minute or two and then restart and it is an endless cycle. The unit turns on and off fine but restarts so often that it is rendered useless.
 
Sep 19, 2018
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10
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Same issue I'm having lol... just got the tv. going to check over the psu and mainboard.... just gonna tear into it this week :)
 
Nov 29, 2018
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I replaced both the main board and the power board in my UN65KU650DFXZA. Neither changed what it was doing. Anyone have any ideas what the next step would be?
 
Nov 29, 2018
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Nov 29, 2018
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Please direct me where I can send this Main board to, to have it corrected. I have searched and I'm coming up empty.. Thank you in advance for your help.
 
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