42 Inch Plasma TV with bad caps

[dropfry]

Greetings. This place is e excellent.

My tale of woe begins with a 42 inch 42PC3D-UD.A1

Here's a link to a very hi res picture of my tv.

One day the picture went out and only the sound comes on.

I opened it up and found 9 swollen Samwha 3300uf 10V caps (Purple squares on powersupply). So I replaced them and tried firing it up. No dice. Probing around with my voltmeter I found a bad fuse on the Y board, so I replaced that as well (Purple square). Now the tv makes a click sound (around where the red box is) and shuts off after about 3 - 5 seconds.

Everywhere else online that Ive looked says to replace the Y, the Y and Z, or the Y, Z and control board. That seems lazy to me. Im buying an oscilliscope off ebay and learning how to use it, even if it ends up costing more than a replacement board.

In closing, does anyone have an idea as to what components I should test out first?

This is the manual Ive been pretending that I know how to use. (I realize this is dangerous, but I try to stay cautious. I ground myself and try to keep away from all the HV stuff.)

[ran]

Re: 42 Inch Plasma TV with bad caps

With all the help I've rec'd on this forum, I wish I had some sage advice to profer, but alas I do not.

...but I hope someone else will chime in with some good info.... I'm curious if you can fix this.

BTW, what kind and how much for the oscilloscope. I've been sorely tempted to get one myself...but have held back due to my ignorance....

[Wizard]

Re: 42 Inch Plasma TV with bad caps

YSUS board is gone due to the fuse popped when the big unobtainium IC failed and shorted out. Get another board. This is two reasons I do not like plasma units is cost of getting parts is expensive and not very component-level friendly repair. Second, these *consume* real high watts (330W to 360W) vs rear projection CRT based (under 250W) or as not as bad with LCD panels but still bit high. I'm talking apple to apples (40" to 42" inch size range).

Cheers, Wizard

[dropfry]

Re: 42 Inch Plasma TV with bad caps

YSUS board is gone due to the fuse popped when the big unobtainium IC failed and shorted out. Get another board. This is two reasons I do not like plasma units is cost of getting parts is expensive and not very component-level friendly repair. Second, these *consume* real high watts (330W to 360W) vs rear projection CRT based (under 250W) or as not as bad with LCD panels but still bit high. I'm talking apple to apples (40" to 42" inch size range).

Cheers, Wizard

Thats troubling, Im still going to go component by component unill I figure it out. Id rather spend weeks looking for some proprietary chip thats coded in a dead language. Maybe Ill google how to program IC's. The internet is a great thing. Ill post any progress or me smashing the bastard with a hammer as it happens.

And to Ran, Its a Textronics 7900 series. Guy sold it to me for $150, Ive seen some sell for 280$ including shipping as-is on ebay. I hear 100mhz is more than enough though, this one is 400.

[dropfry]

Re: 42 Inch Plasma TV with bad caps

Thats troubling, Im still going to go component by component unill I figure it out. Id rather spend weeks looking for some proprietary chip thats coded in a dead language. Maybe Ill google how to program IC's. The internet is a great thing. Ill post any progress or me smashing the bastard with a hammer as it happens.

And to Ran, Its a Textronics 7900 series. Guy sold it to me for $150, Ive seen some sell for 280$ including shipping as-is on ebay. I hear 100mhz is more than enough though, this one is 400.

Wizard: How do lcd tvs stack up to plasma as far as repairing them. What about the LED versions. Are those going to be bullet proof?

[dropfry]

Re: 42 Inch Plasma TV with bad caps

unobtainium IC
Model number: STK795-811A

If anyone else has this problem: here is some similar if not exact situations.

I have no real idea what Im doing other than desoldering and soldering. I hope the IC was faulty on its own and nothing on the board killed it. Glad to see he had the same bad caps I did.

Edit: Our LG's are different model numbers, but the Ysus boards are the exact same.

[Wizard]

Re: 42 Inch Plasma TV with bad caps

Exchanging ICs on any YSUS board is extreme diffcult due to extraordinary heavy copper planes for desoldering. Another issue there might be bad parts on the YSUS board also when was taken out during STK destruction. And that IC might be only in minimum qty required. And I find that suppliers don't sell this IC singly even our electronics supplier don't sell this, just checked moments ago.

Good luck! 150-300 bucks is to be expected. But the 150 is repaired or used board. Bit risky.

Cheers, Wizard

[Wizard]

Re: 42 Inch Plasma TV with bad caps

LCD, LCD with LED lighting, LED DLP are more reliable but expected to have bad caps and occasional IC failure. Mainboard, T-CON (small board between LCD and the mainboard) and other items are repairable or replaced and not too badly on cost. I dismiss DLP that uses lamps and color wheel (they do make noise and do fail on occasion) as these two items cost big fortune to replace when bulbs or colorwheel fails and serious dust magnet. LED DLP does not utlize the colorwheel and no rainbow effect.

Just that plasma panels are the ones worse because of design issues in STK ICs. Samsung have moved away from STK modules for plasma and used far more reliable drivers boards using individual transistors and far more compact.

If you are really wanted to repair your plasma, you want to consider if this panel is 1024x768 or 1366x768 by tallying the total cost and effort and see if you can just toss the tv and get 1080 LED DLP or 1080 LED LCD.

768 or 720 panels are worst to have as there is none that fits for 480, 720 or 1080 (either downconverted or upconverted) and need to use external box or HTPC to scale up to their native resolution to enable 1x1 pixel mode, not all models do this to avoid notoriously bad scaler built into the flat panels sets.

Cheers, Wizard

[dropfry]

Re: 42 Inch Plasma TV with bad caps

Im just going to buy a replacement board and sell this thing for 400 then. If the board doesn't fix it then atleast I can return it. Will post ridiculously elaborate plasma tv smashing if this doesn't work out. (Its 720p) Thanks again for the heads up.

[rogueseal]

Re: 42 Inch Plasma TV with bad caps

I really wanted to know how this turned out as I have the exact same board with same blown fuse and 9 bad caps. Anyone know if the board fixed the issue. I can get a replacement for 70.00 and new caps for less than $15. The TV was being tossed so at least I get an education and can return the bad board. Any thoughts?