Samsung PS-50C96HD - No picture - help needed

[Paul-G]

Background info. - I am currently viewing on an old 26" CRT TV due to lack of funds. I found a Samsung PS-50C96HD on Gumtree for £50 with sound but no picture. Digging here made it look possible to fix so a possible bargain buy. I understand more than your average Joe but need help as fiddling with TVs is new to me.

I have downloaded the Service Manual. http://elektrotanya.com/samsung_f30a.../download.html Overall Wiring diagram attached below.

Observations/findings
I have not yet started to disassemble beyond removing the back cover.
No obviously damaged components in view.
When powered on the Blue light comes on for about a second then goes off.
A single click (relay?) is heard after about a second.
No picture.
Should anything light up on the front panel when a remote is used? Nothing seen.
3 fuses found and checked. 2 on SMPS board OK. 1 on Y-DRIVE board next to the power lead connector CN5707 is blown. Marked 3.6A.

What next?
I do not have a 3.6A fuse but I do have a 3A which is physically bigger but could be temporarily bodged in. Should I do that with fingers crossed just to see if it works for a short while?

Thanks in advance, Paul.

[newtothis]

Re: Samsung PS-50C96HD - No picture - help needed

That fuse would of blown for a reason, Hold off bodging anything otherwise you may damage the set further.

Wait until tom or budm etc take a look, I have no experience with plasmas yet so I can't help

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

I did not bodge it as I also suspected further damage possible. I will wait.

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

Can you post a picture of that fuse?

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

The lighting in the room is not tooo good. I used a small halogen desk lamp to get better light but it isn't the best.

Images are;
The board with a circle indicating the fuse location.
A closer view of the fuse location.
The fuse.

Is that what you are after or do you need something else?

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

Check the surface mount chip on the top right hand board hooked up to the Y-main board (the one with the fuse.) Does it show signs of failure?

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Do you mean the board top left [Y-MAIN SCAN (HIGH)] as viewed from the back?

All chips on Y-MAIN SCAN (HIGH) & Y-MAIN SCAN (LOW) appear to be good. Attached is an image of one of the chips as an example.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Is it worth me removing the E-BUFFER & F-BUFFER boards and checking for shorts as shown here http://www.youtube.com/watch?v=51SZsfH60EY?

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

You would want to check the Y-buffers, which is what you have taken a photo of above, not the E & F.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Same procedure? The Y-MAIN SCAN is in 2 parts (high & low) with a small connector between. I am assuming I need to check for shorts between the connectors to the PDP and the connector to the Y-DRIVE board.

My main question is which pin(s) should I check from on the Y-DRIVE connectors (CN5407 & CN5507)? Both have a single pin marked as 49. Pin 49 on both are closest to the centre connector between the boards. See Y-MAIN_to_Y-DRIVE_connector image attached.

Can this be done without removing the board. Not a problem, just quicker.

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

If you look at my video you linked, you can see me test this same buffer board from a very similar model. It's been a while since I did that test so can't quite remember where the test point is.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Your video? LOL!
From the video it looks like the pin furthest from the middle connector. Off to test so back in a while.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

The good and bad news.

The Y-MAIN SCAN(LOW) board read OL on all pins = good.
The Y-MAIN SCAN(HIGH) board had non Open Circuit readings on most pins = bad.

I uploaded a video of the meter readings while testing the pins on the outside of the CN5401 connector. Most are other than Open Circuit. http://youtu.be/4xVM6HYemkQ

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

While waiting for a response (no dig intended) I have been doing a bit of research.

Quite a few people recommend replacing both buffers and the main at the same time. Parts are not too common in the UK which is frustrating.

eBay has some but research warns against these as they may be salvaged from damaged screen sets and the screen damage probably causes shorts that take out the buffers at the same time.

Parts from China are available at a cost plus a 30 day shipping delay. Can I trust parts from China?

Can anyone recommend a UK source for reasonably priced parts or a repair service?

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

Yep. that's dead. I don't think these TVs blow these buffers when they get cracked screens. But you can replace the top buffer chip.
You also need to repair the Y-main. If the fuse blew you're probably looking at the 88N30W's being bad on one of the large heatsinks.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

While I can replace the 88N30Ws I do not have the necessary kit to remove the buffer chips which is frustrating.

I have to go with replacement parts or a repair service. Recommendations?

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

I have none myself, I'm afraid. eBay I believe has plenty.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Cost saving due to limited budget? The Y-MAIN SCAN(LOW) tested OK, if I can buy a Y-MAIN SCAN(HIGH) at a reasonable cost then I could try replacing any duff 88N30Ws.

How do I go about testing the 88N30Ws? If one or more are duff, will there be other components as well?

[tom66]

Re: Samsung PS-50C96HD - No picture - help needed

There are whole repair kits for the Y-main including every part you need. They include instructions. Such as this one:
http://www.ebay.co.uk/itm/LJ92-01490...item3f2bf62fd8

You can see there are more than 88N30Ws to replace.

[Paul-G]

Re: Samsung PS-50C96HD - No picture - help needed

Thank you for that.

I am weighing up the cost/risk options. I have a feeling that my limited abilities will send me down the Repair Service route at a cost of £120. I could do it cheaper but this way a major user error factor is removed. If I fail in replacing parts and do more damage requiring further parts/replacements the time/cost escalates quickly. After all, I am trying to get this working for my wife for Christmas