Samsung FP-T5084

[MP81]

Hey guys,

I just came into possession of an FP-T5084 plasma from my brother. It would no longer turn on, he tried replacing the fuses again (had a power issue first under warranty shortly after he bought it new, which Samsung fixed, then a second time just out of warranty, which fuses fixed, this time, no dice), but this didn't solve the issue. He ended up purchasing a new 51" Samsung plasma and offered this one to me for free, and mentioned that it was probably the power board, which is about $80 on eBay.

Anyway, I pulled the back cover off, and noticed a couple things, so I just want to get an opinion on which way (or both) to go.

First off, the power board (first three pics). As far as capacitors go, they all look to be in good shape, but I did notice some odd discoloration at the bottom of the board...does this mean I need another power board? My brother had just removed the new fuses he put in the last time, since they didn't fix anything. I'll get new ones if need be.

Second, I did scan other boards for bulged caps, and did find one on the board on the left side of the TV (when viewed from the back - last three pics).

So the question is...what is the likely cause of the problem here?

Thanks!

[R_J]

Re: Samsung FP-T5084

I would start by replacing the bad cap. shown in your last picture. Then check some of the voltages, like vs, va, etc.
Were the fuses blown? if they were blown, which ones? knowing which fuse was blown, if any would point to a problem, like a shorted ysus board maybe??? or is the fuse on the power supply board thats blown, then I would check it for possible shorted fets etc.

[MP81]

Re: Samsung FP-T5084

I'll have to ask him if either of the fuses were bad this last time or not. The one holder (top) looks to be broken, but only on the plastic part, the metal holder is still intact.

[MP81]

Re: Samsung FP-T5084

He said he didn't check whether they were good or not, but replacing them with new ones changed nothing in the symptoms the TV was displaying.

What he said it would do is click like it was turning on, but would just fail to turn on, and it would keep trying that on its own a few times, then stop.

[MP81]

Re: Samsung FP-T5084

So I bought a refurbished Y-sustain board (because I'm lazy, and I hate soldering), which turned out to be an AA1 rev instead of an AA2 rev. The PCB rev is the same, though. The only difference I can see is those gold things on top of the heatsinks are not on the board I received. I'm guessing they just ground the rear cover to the board. All the components are no different, though.

Anyway, I got it installed, put a couple fuses in the power supply board, and buttoned it all back up.

However, upon plugging it in, I get no light up front, and no audible click when I plugged it back in (which I'm used to hearing when plugging a TV in..). So I've got no power somewhere. It's possible my brother had left old fuses in the bag too, so I'll continuity check them when I get home. The one fuse holder that is missing one side of the plastic seems to grab the fuse just fine, but I'll check that too.

If it's not the fuses, any ideas on what it might be? Bad power board too (would that PCB discoloration shown in the first post images indicate this?)?

[MP81]

Re: Samsung FP-T5084

I missed a couple fuses that were hiding on the power board. Have good fuses everywhere and now get power, but it's just to the point of exhibiting the behavior my brother saw, where it sounds like it's trying to turn on 3 or 4 times, and then gives up. The Power LED stays lit for a few seconds, then turns off for 4 seconds, then back on, and repeats.

I'm guessing it probably is the power board and that the cap on the Y-sustain hadn't completely gone yet, but it was definitely worth replacing it now before it did go.

I suppose I'll probably go buy another power board and see if that fixes things.