Vizio 42" Plasma P42HDTV10A Has Slow Startup

[nickelflipper]

Trying to fix a Vizio (P42HDTV10A) 42" Plasma tv, which in turn uses an LG PDP42X32000 screen and associated driver boards. Replaced a few caps that were bulging.

With this model you can short a couple pins on the AUTO GEN plug to display an internal pattern, and I did so. Patterns were fuzzy/snowy for several minutes and slowly got better and better till a decent picture/pattern arrived. Pulled the test and hooked up a Direct tv box, and have the same thing, slow startup till decent picture. On occasion, a loud burst of static over the speakers happens.

Took power board readings and all the 5, 9, 12, 24V rails look good, but can't measure ripple. The Vsc (120V), Vy (-200V), Va (60V), and Vs (187.6) look good too. In taking the Xsus voltages, my probe slipped and took out the 5V 10A smd fuse on the Ysus board. Fixed that, hope I didn't take anything else out?

Don't have a scope handy to test ripple or waveforms, or a ESR meter either for the caps. Here's a pic of the innards and the stated startup condition. Tried some freeze spray to duplicate the cold start up conditions, and no luck.

Any thoughts, or direction on steps to troubleshoot the problem?

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

I would say it might be a bad Vsetup/Vsetdn timing on the Y-sus, but that doesn't explain the static sound, other than it may be drawing too much power from the PSU and causing it to brown out. Incorrect timings can often cause the picture to appear to appear like in the image you have posted.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

@tom66
So you are saying the Control board is suspect, because it supplies the timing to the Ysus board fets? Is the control board a common failure for these screens?

[cadiman]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Do you have any audio?

I hated these vizio L/G panels

No heatsink on the tuner/video processor chip (vizio only).

The control boards do fail but the y or z will go first.

If audio and picture are effected I would look at the first board (below the power supply and in front of the logic timing board center of panel).

You might have a voltage problem with that board causing issues with sound and picture.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Yes, there is good audio, with the occasional burp of static out the speakers, like once in an hour or more, or twice in a few minutes was heard once. There is a still a Taicon 1000uf 16v, and a smaller one in place on the main board. No outward signs of distress, but should probably replace anyway. Replaced a Taicon 1000uf 16V on the tuner board, it was shot.

Will replace the mainboard Taicon(s) tomorrow and report back.

observed/sticker voltages
Va 60/60, Vs 187.6/186, Vsc 120/120, -Vy -200/-200, Vzb 99.8/100

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

@tom66
So you are saying the Control board is suspect, because it supplies the timing to the Ysus board fets? Is the control board a common failure for these screens?

The Ysus has the timing settings on it.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

I would say it might be a bad Vsetup/Vsetdn timing on the Y-sus, but that doesn't explain the static sound, other than it may be drawing too much power from the PSU and causing it to brown out. Incorrect timings can often cause the picture to appear to appear like in the image you have posted.

Since I don't have a scope, is there any harm having a friend look at the screen while I twist the Vsetup or Vsetdn pots (after first marking the current position). Is there a preferred sequence?

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Since I don't have a scope, is there any harm having a friend look at the screen while I twist the Vsetup or Vsetdn pots (after first marking the current position). Is there a preferred sequence?

You can do it without a scope, I've done it before, even on my own (just looking at the picture occasionally.) It's just more difficult as there's a lot of hunting for the "sweet spot" at which the picture looks the best.

I would adjust Vsetup first, as that tends to affect picture discharge... see this training manual: http://www.scribd.com/doc/16077007/L...07-VG-Training for a similar PDP.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

O.K. adjusting the Vsetup, Vsetdn has gotten rid of flashing pixels in the white areas, after the set has warmed up, very nice. Still has the greenish pixel problem when set is cold though, will play with the pots some more. The power supply board had been recapped, and didn't make any difference, so maybe the caps on the little Vsetup, Vsetdn daughter cards, or...?

The main board was replaced, and the burst of static over the speakers is gone. By the way, this condition happened when a large part of the screen was bright white. So a loss of power, or glitch, did occur somewhere on the board.

Thanks for the 50" LG link, it is much better than the one I had on the 42" plasma screen.

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Look for a RAMP_UP potentiometer. Low level colour distortion may occur when RAMP_UP is not set correctly.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Not sure about the Ramp_Up pot, can't find it on the PDP42X3#### YSUS. Here is the link I had, http://www.scribd.com/doc/7580885/LG...raining-Manual

The slow startup seems to be bad caps on the -Vy daughtercard, or Vs input, on the Ysus board. -Vy goes from -234V on startup (bad picture), then settles down to -201.7V (-200V spec) after warmup (good picture). The pot is really touchy on the -Vy, it jumps from -186V to the -201.7V when the set is warmed up. Here is a similarly stated problem and fix http://www.justanswer.com/tv-repair/...irst-turn.html

And since I have replaced all the electrolytics on the power supply board (with still no difference), that leaves the Vs input caps (Samwha 150uf 250V) or the -Vy daughter card caps on the Ysus board? I might add, that the original Vizio power supply caps seem in all regards to be quality caps with the likes of Chemi-Con LXZ, KMF, KMQ, and Rubicon YXG.

What do you think, replace the Ysus board? or go after the caps?

Really appreciate the continued help on this forum.

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Not sure about the Ramp_Up pot, can't find it on the PDP42X3#### YSUS. Here is the link I had, http://www.scribd.com/doc/7580885/LG...raining-Manual

The slow startup seems to be bad caps on the -Vy daughtercard, or Vs input, on the Ysus board. -Vy goes from -234V on startup (bad picture), then settles down to -201.7V (-200V spec) after warmup (good picture). The pot is really touchy on the -Vy, it jumps from -186V to the -201.7V when the set is warmed up. Here is a similarly stated problem and fix http://www.justanswer.com/tv-repair/...irst-turn.html

And since I have replaced all the electrolytics on the power supply board (with still no difference), that leaves the Vs input caps (Samwha 150uf 250V) or the -Vy daughter card caps on the Ysus board? I might add, that the original Vizio power supply caps seem in all regards to be quality caps with the likes of Chemi-Con LXZ, KMF, KMQ, and Rubicon YXG.

What do you think, replace the Ysus board? or go after the caps?

Really appreciate the continued help on this forum.

Someone else had a similar problem on this forum: -Vy would start up low (too negative) and return to normal over the period of a few minutes. I'm not sure what their solution was. It might be possible to replace those small power boards.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Someone else had a similar problem on this forum: -Vy would start up low (too negative) and return to normal over the period of a few minutes. I'm not sure what their solution was. It might be possible to replace those small power boards.

I see that now, here was the post https://www.badcaps.net/forum/showthread.php?t=16274
Don't see that it was ever resolved. I am pretty sure that the board that supply's the -Vy is the PS102 board, both boards seem to be constructed the same. There are 3 Samwha 10uf 400V caps per board, and a smaller one that I can't read at the moment.

I think I will try to recap the small board, and if it doesn't work, then replace the Ysus board.

P.S. Samwha RD series are only 2000 Hr rated https://cdn.badcaps-static.com/pdfs/...ebca370aed.pdf.

[tom66]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

2000 hours is pretty normal for standard caps, but many Samwha (especially the WB and XC series) do not meet this. I've seen more failed WB than I can count! I would count them among the worst brands.

[nickelflipper]

Re: Vizio 42" Plasma P42HDTV10A Has Slow Startup

Recapped the PS1012 board no difference, then recapped the rest of the Ysus, and no diff. either, darn it. I seem to be chasing my tail here :-)

Upon re-looking at the 16274 post, PlainBill talked about checking Vy with the Zsus unplugged and plugged in. Not sure exactly what is accomplished by doing so, but can say the Vy is too low (-234V) with the Zsus plugged in, and takes a while to come up to -201V. With the Zsus uplugged, Vy is -200.4V right off the bat, no variances.

I performed the Vs (186.2V) check on the power supply and did not notice a difference with just the Zsus, and then just the Ysus boards plugged in. With no boards, the Vs is about 199V.

Can a Zsus board have the fuzzy picture, long warm up effect? IPM on the way out? Caps? Or am I just fooling my self into thinking it's a problem? No blown fuses were observed on that board.