Samsung PN51D550 unable to power on

[tom66]

Re: Samsung PN51D550 unable to power on

No startup chime with all boards disconnected?

[ajshoe]

Re: Samsung PN51D550 unable to power on

I'll try it again with all boards disc. Have never heard chimes yet on this set.

[tom66]

Re: Samsung PN51D550 unable to power on

Did you buy it faulty or is it your TV?

[ajshoe]

Re: Samsung PN51D550 unable to power on

got it faulty about 2 weeks ago. I have extra PSB, main, logic, and bought x-MAIN. with X + Y MAIN connectors off (power and ribbon) - unit now powers up with 1 second green LED blink (was 5 secs on - 2 secs off). Power up sequence is 1 click, VA + VS come up and stay, green LED blinks, NO CHIMES

[tom66]

Re: Samsung PN51D550 unable to power on

You can turn off the chime from the menu, so you can't be sure if the original owner did this or not.

[ajshoe]

Re: Samsung PN51D550 unable to power on

replaced main - no effect on chime. checked all voltages - all good.
On logic board VS_CON is 3.2 volts ??? it goes between logic bd and PSB. what is this ??
where does chime setting stored ? Logic board ??

[ajshoe]

Re: Samsung PN51D550 unable to power on

in service manual - VS_CON is VS_signal (conn CN802 pin 4) . don't know what this is ??

did find out that when Y MAIN ribbon cable is connected - unit goes into DRV_RESET (Green LED 5 secs on - 2 secs off).

Y MAIN and X MAIN are dead after checking FETS on back of board.

is there any way to get to reset tv to get chime to work ??
also replaced logic board - no change

[tom66]

Re: Samsung PN51D550 unable to power on

No but one thing you can do it plug in source to HDMI1 then press SOURCE until you hear sound.

[ajshoe]

Re: Samsung PN51D550 unable to power on

got new X Y sustain boards. plugged them in - did not hook up PDP panel. turned on and voltages were there and then decreased (protection circuit - 5 second green led blink on and 2 second off). I then disconnected ribbon cable to x and Y MAIN boards. turned power on, logic board green LED was blinking at 1 sec (normal). 30 seconds later - x MAin popped. some of the FETS blew on x Main board. on these sets - can't turn on power without hooking up PDP ?? This set doesn't make sense.

[capkid]

Re: Samsung PN51D550 unable to power on

If this 51" TV is anything like its 42" counterparts, here are my thoughts: https://www.badcaps.net/forum/showpo...74&postcount=5

[ajshoe]

Re: Samsung PN51D550 unable to power on

agree with that 100 % ! I have played with this set for 1 week - can't disconnect any cables or X - Y sustain bds blow. Got 2 new x and y boards - connected up 100% and turned on power and I have a display !! These sets are junk - last one I work on. Just not worth the effort and built like sh*t. just my 2 cents worth. There's much better designed set out there.

[capkid]

Re: Samsung PN51D550 unable to power on

Nice to see you got it working. Now that you have the hang of these quirky Samsungs, the next one will be easy

[capkid]

Re: Samsung PN51D550 unable to power on

Did you update the firmware on your Samsung? Tom usually recommends this be done after replacing sustains: http://www.samsung.com/us/support/ow...PN51D550C1FXZA

[PJack]

Re: Samsung PN51D550 unable to power on

OK I have a Samsung PN51D550 that is dead to the world. I had the blinking green LEDs and changed out the X board and it powered back up. Fast forward a month and boom goes the dynamite we are unable to power up again.

Pulled the back and this time no green light on the control board just a single click on the power board. Saw a cheapie on ebay and threw that on and no difference so it is not the power board(most likely).

I am willing to throw another X and a new Y at this if needed or trash it as multiple failures drive me crazy. Remote is causing red light on IR panel to illuminate so I am getting power somewhere.

I am a newbie with a voltmeter that will need some detailed explanations (sorry) like where exactly I need to measure power on a board. I suspect power is not going very far though in its present state so measuring isn't telling me much.

Any thoughts? Is it worth another X and a new Y board to trouble shoot?

[capkid]

Re: Samsung PN51D550 unable to power on

OK I have a Samsung PN51D550 that is dead to the world. I had the blinking green LEDs and changed out the X board and it powered back up. Fast forward a month and boom goes the dynamite we are unable to power up again.

Pulled the back and this time no green light on the control board just a single click on the power board. Saw a cheapie on ebay and threw that on and no difference so it is not the power board(most likely).

I am willing to throw another X and a new Y at this if needed or trash it as multiple failures drive me crazy. Remote is causing red light on IR panel to illuminate so I am getting power somewhere.

I am a newbie with a voltmeter that will need some detailed explanations (sorry) like where exactly I need to measure power on a board. I suspect power is not going very far though in its present state so measuring isn't telling me much.

Any thoughts? Is it worth another X and a new Y board to trouble shoot?

This video might be helpful: http://www.youtube.com/watch?v=JjrwTZC5nVg

This may also be helpful: https://www.badcaps.net/forum/showpo...94&postcount=2

If you get to the point where you need to start testing the heat components, post a pic of the metal heat sink components and your meter so that we can guide you further.

[PJack]

Re: Samsung PN51D550 unable to power on

OK finally found some time to work this a little further and get back to the boards.

I watched the video and had a dead logic board was the answer. A new power board did not power up the logic board LED light and there was nothing getting through the logic board according to the youtube video Samsung has up and was linked here.

So now I have a blinking LED on the logic board (once every second with a click every few minutes) and still the set won't power on. When I select the power on I get no change in LED or any clicking sound. Nothing changes.

I saw some stuff on EEDOM resets (no specifics on resetting it on this model) and also tried the Mute 1,8,2 on the remote with no joy on the power up.

I threw an X board set at this thing about a month ago and it worked for a while. It was doing the 5 clicks and blinking LED trick then so I changed out the X boards. Now I have had this power on failure and can't seem to get it figured out.

Thoughts and next steps?

[PJack]

Re: Samsung PN51D550 unable to power on

It also should be noted that when plugged in there is no clicking noise and the logic board LED appears to go through a normal system test and then settle into a 1 per second steady blink.

My guess is I have to do some reset or I have another bad board (the one with all the inputs that the power on sensor wiring runs through). I see no popped caps or any other anomalies.

[aalaap]

Re: Samsung PN51D550 unable to power on

I have this blinking/clicking/not turning on problem with my three year old PS51D550 (full model number PS51D550C1RLXL version I409). A technician looked at it and concluded that the 50DH/DF Y-Main PCB LJ41-09423A part is faulty. He has been unable to locate a replacement part here in India, but I see a bunch of places online offering it. However, those parts are Rev. 1.3, whereas my current faulty board is Rev 1.4. Some are even older 1.0s, and some places are offering newer 1.5s, but I don't think they ship to India.

My question is: Will a 1.3 board work in place of a 1.4 on this TV set? Where can I get a list of what was changed in the revisions?

If I order these things from another country, I won't be able to send it back or get it replaced, so I need to know for sure.

Thanks.

[cndnheat]

Re: Samsung PN51D550 unable to power on

I found a X MAIN board rev 1.2. The current board in the TV is Rev 1.3. Will Rev 1.2 work? Thanks!

[1983kawi]

Re: Samsung PN51D550 unable to power on

This is the only thread I was able to find that had similar issues to mine, even though it is very old at this point. My tv made a noise like the fan on my laptop when it gets hot, then click turned off. I tried to power it back up, but now all it does is click click click and then stops. I took the back off, disconnect the Y board and it didn't sit there and click. I plugged the Y board back in and unplugged the X board, and the tv screen flashed faint white lines like it wanted to come on then immediately faded. I am completely lost on where to go here. I love my plasma, but don't want to throw parts at it and not fix the issue. Does anyone have a guide on where to start from here?