Trying to Save: Samsung PN59D6500DF - Another one Cycling On & Off

[KYBOSH]

Found this one about to go to the dumpster.
No info on it other than it wasn't working properly.
When I plugged it up it started right up but after a few seconds I would restart.
Did this several times and after some thought I figured I would touch up the solder joints to the transformers and MOSFETs (even though they looked fine).

This had no affect on the symptoms and the TV continued to cycle on and off.
I noticed that it was pretty rhythmic so I figured a component was heating up and shorting out a board at a near constant rate. So I went in and disconnected the sustains to see if I could narrow it down.
Strangely enough when I disconnected both sustains (just to see what would happen) I heard the power supply clicking on and off at the same interval still.
Very strange bcos the power supply is supposed to either not power up at all without the sustains attached or power up briefly then shutdown right away.
This is controlled by the mainboard (BN94-04709A). So I have narrowed down my problem areas to the mainboard, T-con or power supply still.
I searched the archives here and found a nearly identical case regarding restarts.

Samsung PN51D7000FF cycling off and on

One sure fire way to tell that this is firmware related is to note if the restarts occur at a constant interval.
I timed my restarts and it occurs every 30 seconds exactly.

So my problem is firmware related and there is no way to reinstall the firmware via the user interface bcos there is simply not enough time before the TV reboots itself.

Is the correct way to do this by swapping the NAND or some other chip out?




Edit to add:
Upon searching the internet for this board I come across a preprogrammed NAND IC1302 that seems to be the solution.
Anyone here care to lend their experience and insight about swapping out these NAND chips?
From the YouTube videos I see online it seems to be a straight forward job given my experience and equipment.
And from a secondary search I see the board is no stranger to IC1302... lotas mentions in another thread that there are nuances with regards to the software of one chip matching the software of others on this board.

[lotas]

The problem may be in both NAND and OneNAND, your programmer supports these chips, have you worked with NAND at least once (you are aware that they can have Bad Blocks and ECC errors)

[KYBOSH]

The problem may be in both NAND and OneNAND, your programmer supports these chips, have you worked with NAND at least once (you are aware that they can have Bad Blocks and ECC errors)

Nope. This will be my first attempt at a NAND swap or reflash. Which one is the ONENand?

[lotas]

Which one is the ONENand?

Nearby, on the right, under the paper sticker is the bga case.

[KYBOSH]

Nearby, on the right, under the paper sticker is the bga case.

I believed that's IC1301.

So its possible both with need to be replaced?
Is this a once in a blue moon situation where it needs to be changed too?
I am only seeing IC1302 replacement chips online and no one is bundling both IC1301 and IC1302 together for the repair.

I will order a replacement IC1302 ($30US) and see if that will solve the issue.
If not I'll have to turn my eye to 1301 as you mentioned.

[KYBOSH]

While ordering the NAND it was recommended that i do the freeze test to verify that the NAND was the issue. Just for kicks and giggles i went ahead and did it as i have never really had the opportunity to do this test. I sprayed the chip while it was rebooting but it keep rebooting. I stopped after 2 minutes. Unplugged the TV and plugged it back in after a minute or two. The TV didnt power cycle at all after that. I was able to get into the menu and everything. Confirmed its the NAND at (foul) play here.