Samsung PN59D6500DFXZA VS_ON only for a second

[danskelly]

Hey all, I've done much search and researching. I've checked the Fast Track, and the Service Manual. I have a good idea of what I need to replace, but I want to bounce it off of your collective genius first.

Here is what I KNOW:

With all cables connected, and power plugged in:

• The panel shows nothing.
• When plugging unit in, the Standby LED blinks 5 times and goes off.
• Standby LED reacts to front panel controls and to remote buttons presses.
• The Vs voltage rises to around 6VDC over a few minutes, and the Va stays at 0VDC.
• The Status LED on the Logic Board blinks 5sec on 1sec off indicating DRV_Reset.
• There is 0VDC on the PS_ON pin.
• There is 0VDC on the VS_ON pin.

Following Fast Track, CN201 and CN1601_3D cables unplugged, Jumper to PS_ON and GND, and Aligator Clip on pins 3-4 on Logic Board, all of the above symptoms persist.


With CN804, CN201, and CN1601_3D cables unplugged and power plugged in:

• There is 3.341VDC on PS_ON.
• There is 0VDC on VS_ON.
• When I Ground the PS_ON pin, I hear the 2 relays click, and Vs begins to rise slowly, and the VS_ON shows 3.21VDC for less than 1sec, and goes back to 0VDC.

This is where I'm using deductive reasoning to lead me to the SMPS being at fault. I have already purchased and installed a Logic Board and an X Main board, both exhibiting the same behavior. At this point, I don't believe it's the Main Board, and since I've already replaced the Logic Board (with an ebay purchase that I cannot confirm it's function, but I can hope.) I'd like to believe it's the SMPS.

So, what are your thoughts?

Thanks in advance!

[Alastair E]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

Short on Vs line--prob Y-sus IGBT's or buffers....

[danskelly]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

Short on Vs line--prob Y-sus IGBT's or buffers....

Would that still be the case since I have the SMPS unplugged from the Y Main?

Is there a way I can troubleshoot and confirm? Can you help me understand better?

[freakaftr8]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

It's most likely the mainboard. These go bad often on the 59d and 51d series. Why don't you try and short power supply on to ground. This is a blue wire going from the power supply to the mainboard. Now test for vs.

[danskelly]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

It's most likely the mainboard. These go bad often on the 59d and 51d series. Why don't you try and short power supply on to ground. This is a blue wire going from the power supply to the mainboard. Now test for vs.

See, I thought so too. And here's why I find it hard to believe:

When everything is connected properly, the Main Board is constantly shorting the PS_ON to GND. I don't have to press the power button on the remote or the front panel. So that's what lead me to believe that the Main Board was bad...

BUT...

When I use the Fast Track (and the Youtube video that everybody links to) to bypass the Main Board (unplug CN201 and CN1601_3d and jumper the pins 3&4 on the Logic board for the test pattern, and ground the PS_ON wire), the same symptoms occur.

So, I suppose that it's possible that the Main Board is bad because it's constantly grounding the PS_ON wire, but I don't think that's the whole problem, if at all.

[freakaftr8]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

Shorting pson to ground is supposed to keep power supply alive. Try this with the connector still connected to the mainboard

That fatstrack guide steered me wrong also with same symptoms.

[ljintexas]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

I have a set of boards from a PN59. Panel was bad.

[danskelly]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

I have a set of boards from a PN59. Panel was bad.

PM'd you about parts boards.

[danskelly]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

Update:

I ended up buying a SMPS off of eBay and installed it. The issue has been resolved.

I have inspected my old SMPS very closely and cannot find anything visually wrong with it. There is obviously a failure in it somewhere, but I sure can't find it.

Given the data I've collected, can anybody suggest where I should be looking specifically? I'd like to fix it and re-sell it if possible to recoup some of my costs.

Thanks for everyone's help!

[ljintexas]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

That is a very complicated smps..

[danskelly]

Re: Samsung PN59D6500DFXZA VS_ON only for a second

That is a very complicated smps..

Okay, cool... I'll just toss it then.