LCD Samsung TV S50HW Zener Diodes Issue

[xboxhaxorz]

We have a TV in the shop with no video just audio. We tested it with a 360 console.

A part timer found zener diodes that were burnt but doesnt know the value. He said i need the service manual to find out, but i can not locate it.

Would the zener diodes be responsible for loss of picture? I flowed the BGA chip before we found the zeners

[tom66]

Re: LCD Samsung TV S50HW Zener Diodes Issue

S50HW doesn't sound like a model number to me; what is the model number of this set? If plasma, it will be PSxxxxxx or PNxxxxxxx, if LCD it will be LExxxxxx or LNxxxxxx

[tw2005]

Re: LCD Samsung TV S50HW Zener Diodes Issue

I'm thinking Plasma Panel S50HW YD02 or others and also the common blown YSUS & Buffer board. Sound,no picture.

Pictures and full panel or model numbers would help.

What BGA are we talking about? What board are the zeners on?

[xboxhaxorz]

Re: LCD Samsung TV S50HW Zener Diodes Issue

S50HW YD01, is the model

PS BN64 00464A

If pics are needed i can provide those too

[tw2005]

Re: LCD Samsung TV S50HW Zener Diodes Issue

I'm more familiar with the YD02, that's the one I've repaired a few ysus and replaced upper buffers on.

I have worked on one YD01 which supposedly would lose picture but have sound. I could'nt get it to fault so reflowed some ysus joints and still going?

If the sustain boards are'nt getting power you'll have no picture but that does not automatically mean it's a bad PSU. If it does not get the signal to turn the panel on you'll see no VSus voltage and that can be related to shorted buffer boards, blown ysus or xsus boards.

I'm sure there'd be a manual out there for most samsungs but you don't get much in the way of schematics.

have not been able to decypher that part number.

[xboxhaxorz]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Is there any way i can find out which zener diodes i need to order
There may be other issues, but the zeners are obviously faulty

[xboxhaxorz]

Re: LCD Samsung TV S50HW Zener Diodes Issue

zeners are in the 3rd pic

[tw2005]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Very toasty. If someone else has the same TV and gets you the colour code. Maybe.

http://www.shopjimmy.com/samsung-bn9...main-board.htm

So it's a bad Ysus(ymain) and most likely buffer boards bad as well. The upper is the hard one to find. I actually used these same buffers to sub for the YD02 model I was fixing which had shorted upper and shorted ysus but different ysus design.

Hopefully the main board is not cooked now with the BGA reflow.

I don't know if yours is a PS50Q7 but it has similar parts.

[xboxhaxorz]

Re: LCD Samsung TV S50HW Zener Diodes Issue

So the ymain board is the fault and that is because of the zeners blown? If the zeners were replaced then the board would work or are there other faults?

How would i determine if the buffer boards are bad? The main board is not cooked since i did a PB flow and not a PB free flow. Since i wasnt sure if the BGA was the cause i did it that way so as not to create additional problems if the BGA wasnt the issue and apparently it is not the issue from the above posts.

[tw2005]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Here's a repair kit which may give a clue to what usually fails.
http://www.ohmsupplies.co.uk/REPAIR-...OF-10-SMD-FETS

The obvious things I'd try and check would be diodes, fets and the IPMs under the heatsinks.

Love to give you more help but not enough experience with the buffers. To state the obvious new ymain and buffers I'd expect will get it going but expensive I'd say.

Never repaired one of these ymains. If it was YD02 I know exactly what FETs blow.

Sorry.

Just noticed with that kit it says 15 pieces. I suspect you'll only get the zeners for one side? I count 19 or 20 components needed, I think?

[ben7]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Good job tw2005!

Damn, those are very fried zeners!

Make sure when you replace them, that you are sure there is no carbon underneath them, which will conduct electricity.

[tw2005]

Re: LCD Samsung TV S50HW Zener Diodes Issue

zener datasheet, not sure if it'll help or the right one

[WesselC]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Hi Guys

I'm new to the forum and can't find what I am looking for.

I own a Vizio P50 HDTV20A TV with Samsung S50HW-YD02 boards.

There is no sound or picture, when I switch it on the green LED will light up and after a while it would turn to amber.
The Voltages are:
Vs - 208V, Va - 65V, Ve - 98V,
The PSU has a "Fault LED" but it is not lit - so I assume the PSU is OK
On the Logic Main board is a LED(LD2002) that start to to blink after about 10-15 seconds after switch on and continue to blink until automatic switch to "Stand By"

Any suggestions on what might be faulty?

[freakaftr8]

Re: LCD Samsung TV S50HW Zener Diodes Issue

Those 8 glass zener diodes are 30v. Just replaced some on a board. Not too.sure.as.to why they blow. Seen this a few times on dell, samsung and others using this panel.