Samsung Plasma 51" PN51D450A2DXZA - No picture

[tleake3]

Ok so I've had this tv for about 4 years. I was at work one day when my wife sent me a text telling me the tv didn't work. I called and she said she turned it on, the screen flashed and went black then started playing sound but no picture.

I went to google and started looking for similar problems. I read that sometimes the Y-sus board goes bad and causes that and that the X-sus/main needs replaced as well as it can go bad due to a bad Y-sus. Correct?

Well I ordered both boards from shopjimmy and replaced them yesterday. Powered the tv up and still a flash on the screen and goes back to black with the red led at the bottom left of the screen flashing about 5 times.

I did more research by reading on here, other places and videos and am now wondering if it's the Y buffer board? When I get home this evening I'm going to check the buffer board for dead shorts and hoping that's the issue. I'm new to working on plasma tv's but not on electronics altogether. Any help would be great.

Thanks.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

On these samsungs normally a bad Y main will kill the Y buffer. I have seen one where a bad X main killed the Ysus and buffer. Do you have a DMM and do you know how to check for S/C ?

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

I have a Fluke T5-1000 but not sure what you mean by S/C.

[TVRepairNoobie]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Probably means the SC Sustains (YSUS, ZSUS)

[lookimback]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

S/C = Short Circuit.

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

S/C = Short Circuit.

Ah, thanks. Yes I do know how to check for a short circuit. I watched a video earlier on how to check the y buffer for dead shorts and I'll do that first thing when I get home this evening.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Best to check all the igbts aka Fets on the Y sustain and X sustains first if you have a blow buffer.

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Ok so I checked the Y buffer and some of the pins that connect to the Y-sus are closed and some open. I did get one of the bottoms connections has some shorts when I'm checking on the SVC-OUTL port but when checking on the SVC-OUTH I get nothing. Same goes for checking the pins going to the Y-sus, some show open and some closed depending on which SVC port I'm on.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Ok what which Ic do the shorted pins go to the top one ? Probably best to now start checking the Y main for shorts check all the output Igbts most likely the shorted parts are on the heatsink nearest to the buffer card in the tv but check them all. Also consider checking the X main as well that can actually kill the Y main if its also bad same testing procedures for both.

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Even though I just replaced both X and Y boards?

The shorted pins on the bottom section go to the bottom IC. All 4 connections have open and closed points going from the buffer to the Y-sus.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

A bad buffer can kill a Y main and possibly X main so best to check them all over before you buy a new buffer.

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

I just seen your post. I'll have to check when I get off work.

Correct me if I'm wrong but I need to check the pins that go from the power supply to the Y-sus?

Also I'm not really sure what an igbt or a fet is. Is it the portions on the heatsink with screws? I'm still kind of new to troubleshooting things like this.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Yes check that the Va & Vs voltages come up the connectors where that voltage should be present will be labeled. If a voltage doesn't come up start unplugging things like the buffer to see if it then brings that voltage up. The Igbts and fets are the devices mounted on the heatsinks on the Y main and X main.

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

After checking my old and new boards with a Fluke 87Ex they're all fine except the buffer board. So I'll be sending the 2 boards I ordered back and getting a refund and order a new buffer board and hopefully fix this issue.

[ReeceyBurger123]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Ok cool and you get the vs and va voltages when you unplug the buffer ?

[tleake3]

Re: Samsung Plasma 51" PN51D450A2DXZA - No picture

Sure did.