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Audiovox plasma - sound but no picture
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Tushy
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PostPosted: Tue May 20, 2008 11:23 pm    Post subject: Audiovox plasma - sound but no picture Reply with quote

I'm hoping you can help me. I recently acquired an Audiovox FPE4216P that is not working.

The previous owner said part of the screen was redish in the top center then extended across the top and down through the center. Then one day, while watching it simply turned off.

Now there is sound but no picture, the power light turns blue but the set shuts down after about 3min.

In addition, there's an LED on the board labeled 667-PH42FB6-20 or 782-PH42D8-200A in the back that does not light up.

Does this indicate this is the board that is bad or does anyone know what may be wrong?

Thanks.
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tushy
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PostPosted: Wed May 21, 2008 7:24 pm    Post subject: New Symptoms Reply with quote

So one of the fuses in the YSUS board (6871QYH953A) were blown. Upon replacing it, the TV will not stay on.

It comes out of standby for about a second (light goes blue from red) then goes back into standby. After this happens, the led on what I think is the power supply board (667-PH42FB6-20/782-PH42D8-200) will come on and stay lit.

If I press power again, nothing.

Any ideas?

Thanks in advance!
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Wed May 21, 2008 11:08 pm    Post subject: Reply with quote

Replace the at least the y sustain.
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Tushy
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PostPosted: Thu May 22, 2008 1:43 am    Post subject: Reply with quote

Thanks for the input minnie.

In the many hours I've spent on the web researching this, I've run across a number of posts that say all three boards must be replaced together which I would rather not do. I believe they mean the YSUS, ZSUS and perhaps the control board? It also seems from the posts I've read about service technicians that come to your house, they replace a board, see if it works, replace a board etc. and basically make educated guesses but don't actually diagnose.

I'm in no way trying to trash you though and am extremely grateful for your help!

It just seems that repairs to plasma TVs are rather hit or miss and am wondering how you came about your recommendation. Is it because of the symptoms I described or because the fuse blew on that board (which had me leaning towards it as well)?

Also, what is the YSUS responsible for?

Thanks so much for your help!
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Thu May 22, 2008 4:10 pm    Post subject: Reply with quote

Yesterday I had a Samsung plasma that after it was on for about 10 minute would get red horizontal lines near the top right corner. I replaced the y sustain and logic board. Theory, the y sustain does the majority of the video processing and is located on the right hand side where the error/red lines are. The logic board does timing. If you have any video distortion, the logic board is responsible for assembling how the information is assembled on the panel. Is it a wild ass guess, absolutely. But it's a logical assumption. The X/Y Y/Z sustain boards drive your voltages left to right. Your buffer boards drive your voltages top to bottom. All that remains basically are your digital main/signal board, logic/timing board, and power supply. It differs from set to set. You have a blown fuse on the y sustain. You replace the fuse but still have no picture. You can look on the panel it will give you the VS and VA voltages that supply the sustain boards. You can test these voltages. IF your VA and VS are good logic dictates the power supply seems to be working. The only other voltage I would look for would be your 5 volt run supply. Now it differs set to set. Now does this set have a y drive board? It's a cost factor. Should you replace the x and y at the same time, yes. Many occasions I have just replaced the y or z sustain and fixed the set. If it's X/Y, Y does the majority, if it's Y/Z, Z does the majority. The logic board really has nothing to do with the power distribution process. A bad logic board would cause no picture to video distortion. If they have a 'kit', it's suggested to do what the manufacturer tells you. If you want, put both sustain boards in. Now mind you, if you do and it works for a bit then blows again or doesn't work, you could have a bad panel.
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PostPosted: Thu May 22, 2008 8:47 pm    Post subject: Reply with quote

Whoa. Excellent information, much of it over my head but I think I get most of it.

I'd like to try to remove the power board from the equation first. I should "look on the panel it will give you the VS and VA voltages that supply the sustain boards. You can test these voltages". I see on the YSUS board at the connector, pins labeled 5V, Va, NC, VS, VS and 4 grounds.

Which "panel" will list the expected voltages and should I unplug the connector, power up and test the appropriate pins running off the power board or try to do it while still connectd? I don't want to disconnect anything, power up and cause more damage.

"does this set have a y drive board?" - I think so. It's got a YDRVTP, YSUS, ZSUS, CTRL, XRRBT, a board connected to half the inputs, board connected to the other half and coax in which I would assume is the tuner and then a little board fed by the CTRL board.

I am unable to find kits so would have to replace boards one by one anyway and the company no longer supports this model or carries parts for it.

My greatest fear is that after pouring hundreds of dollars into the TV, nothing gets fixed or it's a bad display panel.

Thanks for taking the time to help me be relatively sure of which part(s) are bad.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Thu May 22, 2008 10:42 pm    Post subject: Reply with quote

The 'panel' is what you look at or from the back the 'big' silver thing all the boards are mounted on. There should be a white sticker with the VS/VA voltage. In your case it would be the YDRVTP, YSUS, ZSUS, or the Y drive board which may or may not come on the Y sustain, Y sustain and Z sustain. But going back to the fact the Z sustain is bigger than the Y sustain which means the Z sustain does the majority of the processing, and the fuse is popped on the Y sustain, you need the Y sustain, Y driver, and Z sustain. Look at the plugs and check your VS/VA. You can also disconnect the sustain boards and read the voltages. Yes it sucks when you order hundreds of $ in parts and it's the panel.
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PostPosted: Fri May 23, 2008 12:35 am    Post subject: Reply with quote

Thanks again.

When I unplugged the YSUS, the blue indicator light on the front stays on for about 3 min so I was able to take some readings.

The Va fluctuates between about 34v and 5v. The two Vs leads go between about 30v and 4v and end up settling around 16v. The voltages listed on the panel are Va 60v and Vs 186v.

I guess that this would mean that that board needs to be replaced. There are two pots labeled Vs adj and Va adj. Do you think I should mess with them to try to get more juice?

Also, my YSUS board (6871QYH953A 6870qyh005B) is physically larger than my ZSUS board (6871QZH956A 6870qzh004b).
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Fri May 23, 2008 2:35 pm    Post subject: Reply with quote

What do VS/VA read with the boards plugged in?
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Tushy
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PostPosted: Fri May 23, 2008 11:48 pm    Post subject: Reply with quote

Hi minnie,

With everything hooked up again, the Va and Vs reads 0v.

As I mentioned before, since I replaced the fuse in the YSUS, when I plug it in and press power, the light on the front goes from red to blue for a second then back to blue and the red LED on the power board lights up. Once this happens, pressing the power will no longer let the light on front go to blue unless I unplug the set and plug it back in again.

Also, there is a jumper that says "closed: auto, open: normal". Right now it's open.

Most (if not all) of the boards are LG. the panel itself says PDP42X3#### if this helps clarify anything.

Thanks
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