Hyundai HTP4240 fault (LG PDP42V6 chassis)

[ProDave]

First time repairing a plasma, lots of CRT and LCD experience but first plasma, so can you point me in the right direction.

This old Hyundai set uses all LG PCB's except psu board and uses an LG display panel.

The fault as best as I can describe it, is every vertical pixel shows the same.  So for instance select an AV source with no input connected, instead of just seeing the text describing that AV input in the corner of the screen, you get solid bands right down the screen where every character would be.

Any clues where to look? is it likely to be a repairable fault, or a dead panel?

[Turnip]

Hi ProDave,

Seems a bit like lower Y drive problems together with a suspect Y-Sus - Try back threads, and/or give board details (what model) and a piccy (of the piccy) - Chris

[ProDave]

I've identified this set uses the LG PDP42V6 chassis and I've found a free download for the service manual here http://monitor.espec.ws//files/pdp42v6_843.pdf

My fault does not fit any of the standard faults described in the service manual.  I've taken some screen shots to try and demonstrate the fault:

The first shows an unused video input selected.  The bands down the right hand side are what I believe to be the text describing the av input and change according to which input is selected.

The second shows trying to receive an analogue off air broadcast with no aerial.  at first glance it's fairly normal white noise, but note it looks odd in the vertical plane.

The third is trying to display the menu from a freeview box connected via scart. The big whiteish block is the menu on the freeview box, and once again the bands at the right are indicating the AV source in use.

I've established that this is only a 480 line panel in this set, so it's not worth much and not worth spending a great deal of time or money on, but i'm interested to track down which boards are good and which are faulty, if for no other reason than I can sell the good boards.

[Turnip]

Hi ProDave,

Your second piccy is exactly what I saw on aerial analogue - went to Quuq for advice, and a certain revered 1st Hero - 'LG' Tony suggested the lower drive and Y-Sus bit - they did the biz.

Confess get me bits from recycling depots - on the cheap - just as well, as cust was head-honcho in depot - Chris.

PS - if curious - check back threads

[ProDave]

I've done some more work.

Firstly replacing the 33uF caps restored the 15V to correct value but still the same fault.

But now I've disconnected the lower buffer and now have a working top half of the picture.

So I definitely need a lower Y buffer board, and quite likely a new Ysus board as well.  It all depends if anyone can offer me those two boards cheap enough to make a repair of this set worthwhile.

Do I really need a new Ysus board?  It's been suggested that the faulty Ysus blew the buffer, but was the fault not just the failed capacitors (which I have fixed) or is there likely to be a different fault with the Ysus board still?

[Turnip]

Hi P/D,

Interesting thought - replaced Y-sus as I had one from a Screen Smash, and as knowing folks said I needed to, even after those 33mfd caps were replaced.

Wonder about any further thoughts -  ?   Chris.

[ProDave]

After researching the market, I decided to scrap the set.

Looking on ebay and watching a few, these seem to sell in working order for about £150.  The problem is their weight is too much for cost effective postage, so limited to collection only.  Indeed there was a fully working one on auction in Newport, Wales, that didn't sell at £0.99 (I wish I was closer, I would have snapped that up)

So it would have cost me about £80 to fix it to get no more than £150 when I sold it.  So I decided to dismantle it.

I've sold £50 worth of boards so far and should get at least as much when I sell the rest of the good boards, a bit more if I can sell the panel.

Sometimes the art of making money from tv's is to know when NOT to repair them.

[Turnip]

Hi P/D,

Guess you're right - have spent loads of cash just to try prove a repair point and sold sets for less than repair costs.

Well, starvation fends off heart problems for an ex-smoker, so checking into DIY drink - treading local sugar beet - hard on the toes  - Chris.