Samsung PN51D550 unable to power on

[Zak_Vinni]

Re: Samsung PN51D550 unable to power on

Hi tom66,
I have a similar problem with my Samsung PN51D550, I unplugged x main board and clicking disappear and it looks like tv turned on (I assume black screen is due to no cable plugged to the tv) - so, does that mean x main board is the problem?
Thanks.

[tom66]

Re: Samsung PN51D550 unable to power on

It is a very common failure on D450/D550, which are similar but I think 720p vs 1080p, basically same TV otherwise. I have a feeling it won't power up fully with X-main missing due to detection circuit. After replacing X-main it is vital you apply the software updates to your TV as it reduces the chance of future failures.

[Zak_Vinni]

Re: Samsung PN51D550 unable to power on

Thank you.
And is there is a way to repair existing x main? I pull it out and all capacitors look ok, but it's hard to test transistors in circuit, would you suggest anything?

[tom66]

Re: Samsung PN51D550 unable to power on

If the board is under $40 then it would not be economical to do so as you'd probably be looking at $20~$30 to replace all failed FETs/IGBTs, plus whatever you value your time at.

[Zak_Vinni]

Re: Samsung PN51D550 unable to power on

Thank you for reply

[Zak_Vinni]

Re: Samsung PN51D550 unable to power on

Just received and installed x board yesterday, worked fine, but today exactly the same problem... need help.

[3dron]

Re: Samsung PN51D550 unable to power on

Ever figure out why replaced board world for only one day? I unplugged x-main and get no response from tv. is this also a bad x-main? (as I read yours extra lily powered on black without the x-main.)

I have same PN51D550. Nothing looks burned out. And green light on logic board goes on for one second then off for 3 second. Repeating pattern 5-6 times.

I had same issue during warranty and Samsung authorized repair replaced something after 1 month new, but I was not present. Now tv died at 13 month mark.

I have pics of all, maybe you can even tell which part was replaced before.

Thanks all for any help.

Ron

[3dron]

Re: Samsung PN51D550 unable to power on

I am sorry I meant to say I get no clicking sound after unplugging x-main. I only get 5 second steady green light, then silent green off for 2 seconds. pattern repeats indefinitely.

I hope this is just bad x-main. Does y-main ever blow at the same time?

Ron

[tom66]

Re: Samsung PN51D550 unable to power on

Can you post some pictures of inside the chassis?

Sometimes the X-main can damage the Y-main, and vice versa, on these chained energy recovery plasma panels.

[3dron]

Re: Samsung PN51D550 unable to power on

Here are the images.

[tom66]

Re: Samsung PN51D550 unable to power on

Your set looks to combine X-main and Y-main energy recovery, so it's possible a bad X-main kills the Y-main.

Have you tried powering the set on with X-main unplugged? It will probably not power on but you might get a different code from the control board.

[3dron]

Re: Samsung PN51D550 unable to power on

I am sorry I meant to say I get no clicking sound after unplugging x-main. I only get 5 second steady green light, then silent green off for 2 seconds. pattern repeats indefinitely.

I hope this is just bad x-main. Does y-main ever blow at the same time?

Ron

Tom66, if you are referring to my images, yes I did unplug the x-main. From above info does that tell you anything?


Is there a test of just unplugging the y-main?

[tom66]

Re: Samsung PN51D550 unable to power on

5-2 blinks is DRV RESET but I wish I knew how to locate which board caused it. I do not. Not much experience on these modern Samsungs.

[3dron]

Re: Samsung PN51D550 unable to power on

So does this mean

1) it is NOT just a replace of x-main?

2) Or does this mean it could be x-main and something else?

3) Or not x-main for sure, and something else?

4) "Fill in the blank"

[tom66]

Re: Samsung PN51D550 unable to power on

Replacement of X-main, Y-main and Y-buffer is the safest way to do it, assuming that an oscilloscope is unavailable to test any one board.

[3dron]

Re: Samsung PN51D550 unable to power on

Can replacement boards have different rev. numbers. Can I get an x-main with a R1.2 version be used with an y-main with a R1.3 version?

All other numbers between the old x-main and the new x-main are the same. (ame model NO, PCB NO, PBA NO HD, FHD)



Also do the ink stamps on the heat sinks matter? Some have matching numbers on pcb, but are stamped slightly different like DH G, or DF S or DF G. I do see the model number on this pcb is 50' DH/DF. So are all these boards the same if all matches except the black ink stamped heatsink.

[tom66]

Re: Samsung PN51D550 unable to power on

If you change the rev number, you need to change the control board to same rev number and all the other boards must be the same rev number. Sometimes you can get away not doing this but not always.

[ajshoe]

Re: Samsung PN51D550 unable to power on

I have the exact same tv (samsung pn51d550). have exact same condition - plug it in, green led is on for 5 seconds, off 2 secs. DRV_RESET. power actually is all good for a second and then drifts to zero. tried forcing PSB on - same code and PSB result. Is there a way to find out which board is telling the main board to shut down the PSB ???
Also - if I put in new x Main and y main, can I power it up without connecting PDP cables ?? Or will it still shut down the PSB with DRV_RESET.

[tom66]

Re: Samsung PN51D550 unable to power on

An error will usually be detected if the panel is not connected.

[ajshoe]

Re: Samsung PN51D550 unable to power on

I also have no start up chime. is the main board the only thing responsible for this (assuming the PSB voltages are good) ?
Does anyone know a way to detect the board that is making the DRV_RESET status code blink ??