This is the zombie UN55NU6900F I wrote about in [URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-tvs-and-video-sources/3566892-zombie-samsung-un55nu6900f-dead-no-standby-voltage-randomly-came-to-life-after-hours-of-troubleshooting-then-died"]this original post.[/URL]

It originally was completely dead with no standby voltage. After some poking around, I found the solder at RM819 (see pictures) failed. I removed it from the board, it tested fine, resoldered it, and now the TV works.

The expected standby...

Hi everyone, Im just a hobbyist that likes to tinker.

Ok so after countless hours in the evenings this week testing stuff and figuring out how the circuit works, it appears that RM819 the 2R2 SMD resistor connected to the VCC pin on ICM801 was the culprit (so far).

When I initially measured resistance I was getting super high / unstable numbers so I thought my leads just weren't making contact. When it randomly started up the first time earlier this evening (mentioned in the OP), I had lightly abraded the surface of the contacts with my MM leads and noticed the resistance fell to more reasonable levels around 5-10ohms. Still higher...

They look fine from the back but I don't really novice so I wouldn't know for sure. I noticed some on the solder didn't go all the way to the top of the board one some of the joints near DP81XC (see the two blue caps CP810 and resistors RP824 and RP822), would that matter as well?

DP811C / DP812C / Transformer solder joints
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CP810 and RP824/822 Solder Joints
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This is my first attempt at troubleshooting a board like this, I know I could just buy a new board but I'm curious to figure out how this works. I've been testing different components in the evenings this week and I think the problem is with the IC failing to start up for some reason. When the board is plugged in there is no standby voltage.

Then today it randomly sprung to life like a zombie but shortly died thereafter. I have no idea why it would have done that and its the first time I've seen it running. I discharged capacitors on the board last night, then it was sitting today....