Samsung ps51d6900 dk will not switch on

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

I used this meter for years and has been reliable as I use on for automotive and house electrics.

So if it's reliable can we safely say it's the buffer board?

Can we do any other tests to confirm?

Do you know what can cause this?

Would this have anything to do with the red/pink tinge on white backgrounds that I had noticed lately?

Sorry for all the questions, you have been a great help and it's much appricated😀

Cheers
Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

The buffer board -looks- bad however, I do like confirmation. Can you tell me the make/model of your meter? The test of voltage between OUTL and OUTH will confirm a bad board. Hopefully it's possible to lock the meter in volts to get a measurement.

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

This is it.

http://www.fluke.com/fluke/m3en/elec....htm?PID=56125

I will get another meter tomorrow to confirm.

Cheers
Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

Looks pretty fixed - interesting... Never seen that before. With regard to red/pink tinge it's an unrelated issue common to C- and D-series Samsung plasma TVs and is easily fixed by making a small adjustment to the Vs voltage. The factory default 207V is too low, it should be set to about 212~215V.

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Ok will I just order one or would you recommend I double check?

Thanks for the info on the voltage, I will look into that when I fit my new board.

Would it just be wear and tear that caused this fault or something else?

Thank for all your help, I was going to buy a power board today so that would have been a waste of money.

Thanks again
Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

Wear and tear failure.

Be cautious when buying boards - in general buffer boards tend to be the most easily damaged boards from scrapped TVs. This is because when the screen is cracked, it can short out the buffer board.

You should ensure the seller has thoroughly tested the board and they offer a returns policy in case they lie about testing it (many do.) Here is how to test a board:
https://www.youtube.com/watch?v=51SZsfH60EY

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

So avoid the ones saying they are from a new TV with cracked screens unlees they offer a full refund if the part does not work.

Looking on eBay, it has massive amount of them ranging from £10-50, just need to see what one offers the best warranty!

This TV has a very small crack in the glass from 6 months ago when it got hut by a yo-yo, so could that be what has caused it to fail then.

Thanks again Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

Hmm, test your buffer (after removing it from the TV) as indicated in my video linked above, if it beeps in the approx same vertical position as the crack on the panel the panel could be bad.

The crack in the panel could cause a failure in the buffer to occur, which would mean the new buffer would also fail quickly. Sadly this wouldn't be fixable.

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Hi tom
I have removed and tested the panel per the link and found the second top set of wires to be faulty. Only the first three from the probe in the attacheched picture. Does it just take one to be at fault to loose the whole screen?

Would I be right to assume the position of these wires run the full lenth of the screen? then this is roughly where the crack is!

Cheers
Chris

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

I have found a NEW board and as something this delicate I would prefer new. The only thing I can see differently is the rev and date would this be a problem?

http://shop.sjstv.co.uk/lj92-01809a-...new-2525-p.asp

Cheers

[tom66]

Re: Samsung ps51d6900 dk will not switch on

Hi tom
I have removed and tested the panel per the link and found the second top set of wires to be faulty. Only the first three from the probe in the attacheched picture. Does it just take one to be at fault to loose the whole screen?

Would I be right to assume the position of these wires run the full lenth of the screen? then this is roughly where the crack is!

Cheers
Chris

The drive lines do run the length of the screen.
If the short is there, then it is an awful bad coincidence that the panel is also cracked there.
Installing a new board might fix the TV, but it could fail in a few months, or it might fail immediately. It is hard to be sure.
That SJSTV board will be fine if all connectors are the same - rev number not important for those boards.

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

I will try it and see how it goes, I'm hoping the fact that it's lasted this long after taking the knock, that it will at least last the same length of time, as this is new and not been bumped.

I will test the new board before I fit it, it it blows straight away at the same point then I know the screen has had it.

The part is arriving tomorrow and I will keep you updated👍

Do you have any links to the voltage setup if the new board works?

Also do I need to test anything else before I plug it in?

Cheers
Chris

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Hi tom

Unfortunately this has not worked, I have redone your test and the results are as follows

1. VS-ADJ = starts at 207v then drops to under 10v (same as before)
2. VSCAN = holds a solid -187.3v then after about 15 sec drops right off (it did this the last time but quicker)
3. VSC-OUTL TO VSC-OUTH = nothing with the power on or off, volts or ohms.

Does this point to the screen or something else?

Cheers for your help
Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

Can you remove the board and check for shorts - are they in the same locations?

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Just removed the boards and it has no shorts.

[tom66]

Re: Samsung ps51d6900 dk will not switch on

OK, can you check across VSC-OUTL to VSC-OUTH but with all the orange ribbons on the buffer board disconnected?

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Ok with all the ribbons on the left hand side removed, I am still getting no volts across those points.

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

Hi tom

Do you have anymore ideas?

Cheers
Chris

[tom66]

Re: Samsung ps51d6900 dk will not switch on

It is possible that the bad buffer board damaged the Y-main, but that is rare. Is your new buffer board shorted across those points?

[Miller r5]

Re: Samsung ps51d6900 dk will not switch on

I removed the ribons on the left hand side and I'm getting nothing on VSC-OUTL to VSC-OUTH volts or ohms.

Is that the points you want tested?