Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

[SoftwareHack]

Well, finding this site is somewhat discouraging since it seems like this power cycling issue is fairly common for any brand of flat screen TV's no matter what model. But, I still want to see if it's something that I can fix. I'm a retired software hack so my hardware skills are limited, but I am mechanically inclined and I can solder PC boards when necessary. Testing is limited to a multi-meter at this point as that's all I have.

I've been going through dozens of threads on this topic for different TV's. It seems that most of the time, the problem is with the panels themselves, but I'm hoping that's not always the case. Here's what I've tested so far:

Samsung UN55KS800DFXZA ver. AA02
Power Board: BN44-00878A (on board)
Main Board: BN94 10960Y (on sticker)

1. Power board - connected only to the backlight, main board disconnected. Backlight stays on while plugged in.

2. Power board - connected to the backlight and main board. All other connectors on the main board disconnected. Power cycling continues again.

3. I've just begun to take measurements off of the connectors on the power board so I don't have that data just yet.

4. Reseated all cables and visually inspected them for burns or damage, with nothing found. Also, visually inspected both boards without finding any obvious burnt parts ore bulging caps.

This lead me to believe that the problem is not the panel, but one of these boards and most likely the main board (or firmware on the main board). It doesn't seem like it's a panel problem so far, but I haven't taken enough off to see the LED strips, etc. Does this sound like a more likely scenario than a bad panel?

I'm still continuing my investigation and learning along the way, but I wanted to see if my thinking is on track or not.

TIA

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

Does this use the one connect? if so I think I would take the lid off and see if there's anything obvious wrong and maybe check some components in there. Having same problem with mine, doesn't use the one connect, on mine the bl-on never goes above .16 volts, should be around 3.3, tv cycles on for 12 seconds, off for 2 so can't do a reset or a firmware update that I know of, checked my lower pins on the connector using a needle, they are tiny and hard to access. Going to freeze my eeprom next see if there's any change, thinking it's their bs flaky firmware or the processor has gone bad. Hate sammys only messing with it cuz it was a freebie.

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

Yes, it does use the One Connect, but I disconnected it for the sake of minimizing the number of sources of the problem. I'm working on it because it cost a $1000 a couple of years ago...

I need to continue with the testing and measuring, but I just thought it was curious that I get the power cycling when the main board is connected to power but nothing else. It doesn't seem like it would be panel related, because of this. But maybe I'm missing something.

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I think if the backlights come on when unplug powerboard to mainboard cable, that verifies powerboard and backlights, check all the voltages at the powerboard connector, my bl-on is very low.

[RJARRRPCGP]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I'm working on it because it cost a $1000 a couple of years ago...

As recent as 2018?!

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

as recent as 2018?!

2017

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I think it's the shitty software gets corrupt, if so need to reprogram the eeprom/spi/nand or freeze the shit out of it long enough to update thru usb. I did the hours of detective work figuring it out, I don't get paid here so nobody else should either, if anyone feels a need...PLEASE donate to childhood cancer or any other worthy cause.

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I also think it's shitty software upgrade or the upgrade process that got messed up.

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I'm going to try the "Freeze NAND" trick to see if that works for me. However, I don't have a schematic and the service manual doesn't identify IC's. I'm assuming that this part: Samsung KLMBG4GEND-B031, is what I need to freeze.

I am curious though if there are multiple flash chips as there is a TCON FLASH DOWNLOAD port and an AGING & MURA FLASH WRITE port.

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

What does it say on the chip, look closely around the board by the chip, it should say spi or nand in that area if so you got the right one.

[Diah]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

yes this which marked with circle are the NAND..

out of the topic.. in 2 days listed here same fault with Samsung.. its sound fishy they send just small code like 0x.. via network to cause this..!!! samsung will do it with out doubt..

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I'm a believer Diah, I don't trust them at all, I'm definitely turning off auto update if I get my pos going.

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I'm wondering what to try first after freezing, a factory reset or a firmware update? thinking a reset will be useless if it's borked firmware?

[Diah]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

factory reset via service menu ---Option.. reset via setting menu didn't fix it

[nomoresonys]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

Ok, I'll try reset menu first, thanks.

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

Well, I struck out. Local electronic supply shop didn't have any kind of freeze spray and I don't like how wet compressed air can held upside down makes things (right side up isn't cold). I'll order online and wait, no hurry. Meanwhile, I'll use a needle to get to lower row pins on the connector.

[Diah]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

Well, I struck out. Local electronic supply shop didn't have any kind of freeze spray and I don't like how wet compressed air can held upside down makes things (right side up isn't cold). I'll order online and wait, no hurry. Meanwhile, I'll use a needle to get to lower row pins on the connector.

some time DIY always helpful , 2 -3 ice cube crash them or with out crash..put them inside cloth and put it on the top of the ic.. wait 3 minute then turn on LOL

[SoftwareHack]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I was thinking about freezing a metal bar, wiping it down, and then putting the bar against the chip.

[Diah]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I was thinking about freezing a metal bar, wiping it down, and then putting the bar against the chip.

yours DIY Idea more Modern LOL

[diif]

Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem

I was thinking about freezing a metal bar, wiping it down, and then putting the bar against the chip.

Butane(lighter gas) is super cheap and will freeze far better than a cold metal bar.