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**tw2005** · 08-06-2013, 03:26 PM

Re: Plasma turns on, but shows no picture

Post pictures of the layout and boards. familar fault with Samsung, sound no picture, generally bad Ysustain and shorted buffer boards. yours may be an earlier version than the one I'm thinking of but you don't always visually see a blown buffer IC.

have to resistance check.

At the start of this forum there's some stickys for tips, guides, manuals, and Tom has a video of buffer checks etc on a Samsung.

**capkid** · 08-06-2013, 05:42 PM

Re: Plasma turns on, but shows no picture

It might be helpful to post at least the Y-Sus part number to figure out the more common US version of this TV.

**Daysleeper** · 08-06-2013, 10:26 PM

Re: Plasma turns on, but shows no picture

Hello and thanx both of you for your answers

The part numbers are as follows:

Panel: S50HW-YD01
Y-Main: V5.0 LJ41-3078A / R1.7
X-Main: LJ41-03335A / R1.3
Logic Main: 50"HD V5 LM / R1.0 LJ4103971A
Power-Supply: PS-505-STD LJ4400113A
AV-Board: iSolution 200-100-Ex52-D

From what I've read Ysus = Y-Main?

@tw2005
I wasn't able to find the mentioned video of the buffer checks. Could you direct me to it? Well the starting sound comes up when I turn it on. Don't know if it works for AV-Sources too, but I suppose it does.

Attached Files

**Daysleeper** · 08-06-2013, 11:49 PM

Re: Plasma turns on, but shows no picture

What I forgot to mention: The TV seems to have problems to wake up from standy sometimes, meaning the pushing the power button would not turn it on. Had to unplug the power completely, then it worked again. It also did that when it was still working.
Could it just be a software issue? Is there a way to reset the TV?

**tw2005** · 08-07-2013, 04:24 AM

Re: Plasma turns on, but shows no picture

Try

https://www.youtube.com/watch?v=25HT...tCVe9&index=13

Post 6

https://www.badcaps.net/forum/showthread.php?t=25836

That's the next model from yours but the buffers are near identical.

**Daysleeper** · 08-07-2013, 01:00 PM

Re: Plasma turns on, but shows no picture

Hello, thanx for the links. I watched the first video before, but it didn't help me with my problem. There seems to be a bulged cap and a blown fuse the cause.

Sorry, but I don't know what you mean by post 6. If I follow that second link and go down to the 6th post, it shows a set of videos but none seems to deal with my problem.

Could you probably be a bit more specific?

I noticed that two of the fuses on the Y-Main have a resistance of 5 ohm's. Isn't that a bit to high or still okay?? Read in some other FAQ it shouldn't be higher than 0,3 - 0,4 ohm's.

I also checked the IC's following this video:

https://www.youtube.com/watch?v=51SZsfH60EY

The Board seems to be very similar to mine, so I hope the pinout of the connector is the same. No beeps, so it seems the Buffer-IC's are okay.

I also read about selftest for the control-board, but I'm unable to find the right jumper pins on my board...

**capkid** · 08-07-2013, 02:28 PM

Re: Plasma turns on, but shows no picture

The Dell W5001CHD comes up when I search using the Y-main and X-main part numbers you listed:

http://www.shopjimmy.com/samsung-lj9...main-board.htm

Are you sure about your 5 ohm fuse readings? Yes, the fuses don't usually read that high.

**Daysleeper** · 08-07-2013, 02:55 PM

Re: Plasma turns on, but shows no picture

Hi! Thanks.

Well this could actually be the hint I was looking for. Searching for Dell W5001CHD on youtube brought up this video:

https://www.youtube.com/watch?v=xcIuAhSCBjM

I already noticed that something might be wrong with those zener diodes, but wasn't entirely sure about it. I'll replace them and post then back!

**capkid** · 08-07-2013, 02:58 PM

Re: Plasma turns on, but shows no picture

I saw a second video earlier that mentioned replacing zener diodes on the Y-Sus for the Dell, also. I'm not sure if that's your issue:

https://www.youtube.com/watch?v=kRzk9MzzzdA

**Daysleeper** · 08-07-2013, 03:56 PM

Re: Plasma turns on, but shows no picture

Jepp, this seems to be the same issue. I just measured the zdiodes on the lower side and they all seem to be faulty, the ones on the upper side should be okay. Gonna buy some replacement zdiodes by tomorrow. Hopefully it works

If it does, the question remains what caused them to break. A too high voltage from the PSU??

**tom66** · 08-07-2013, 03:57 PM

Re: Plasma turns on, but shows no picture

Likely, with most failures, running hot due to under-rated components (a penny saved looks good on the budget!)

**Daysleeper** · 08-07-2013, 04:09 PM

Re: Plasma turns on, but shows no picture

Does this mean I should continue checking on other parts before replacing the zdiodes? The power supply seems to be okay.

Then again, the power-lines in the house I'm living are... well gently spoken... of lower quality. I'm getting some nice sparks every now and then when I put a plug into the wall. Maybe those fluktuations in the power-net caused the diodes to die??

**tom66** · 08-07-2013, 04:12 PM

Re: Plasma turns on, but shows no picture

Sparks when plugging in have nothing to do with power line quality, and external fluctuations will not affect the Y-/X-main.

**Daysleeper** · 08-07-2013, 04:14 PM

Re: Plasma turns on, but shows no picture

Okay. So you think the PSU is faulty and caused a peak that fried the diodes?

When I turn on my soldering iron this causes my external VGA-Upscaler-Board to produce a flickering picture while it's on. The TV (when it still worked) did the same, so I could not use the upscaler with that TV. Stuff like this makes me think the power-net here is a bit troublesome...

**tom66** · 08-07-2013, 04:17 PM

Re: Plasma turns on, but shows no picture

No. As said above, they were originally inadequate for the job, likely due to cost cutting or poor engineering decision, and they failed because of this. (You wouldn't blame a bolt shearing off in your car on shoddy suspension, but on the bolt being poorly made.)

**Daysleeper** · 08-07-2013, 04:31 PM

Re: Plasma turns on, but shows no picture

Oh, you were referring to the zdiodes as the "cheap" parts! Sorry, it's late. For some reason I was thinking of them like fuses, which usually don't blow without a cause.

Then I'll replace them and post back results

Thanx alot!

**Daysleeper** · 08-09-2013, 05:15 AM

Re: Plasma turns on, but shows no picture

Feedback:

It works again!!

I replaced the z-diodes and the picture is there again.

Thanks for all of your help, especially capkid for pointing out that Dell issue. I would have never figuered that out on my own.

I only noticed a flickering on the screen unfortunately when there is no signal (blue screen). When a signal is recieved, it doesn't seem to be there. Have to do some more testing later on. I couldn't buy z-diodes with the same part number, only with the same values (30v, 500 mW). Could this cause the flickering?

Thanx again to you all for the great help

**tom66** · 08-09-2013, 05:34 AM

Re: Plasma turns on, but shows no picture

You may have to adjust the Vs, Vset, -Vsc and Ve voltages to match the sticker carefully. If that fails, you'll have to play with the Yrr and Yfr controls.

**Daysleeper** · 08-09-2013, 07:08 AM

Re: Plasma turns on, but shows no picture

I lowered all the values a few volts until they matched the sticker, but they seem to raise up again afterwards from alone. And the flicker got worse...

For VS and Vset I cannot turn even turn the screw any further, though they're still 10-20 volts to high...

What do you mean by Yrr and Yfr? I can only find on more screw labeled VPFC.

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