Panasonic TX-51P100

[fire]

lcaillo & others - thanks for the information provided in this thread (it is by far the most detailed on the internet)


Nevertheless, after having read through the thread, I have a 51" panasonic rear projector TV (TX-51P100), and have some convergence problems which i attempted to fix by replacing the STK's and checking all resistors against their colour bands.
Initially, the screen used to have an arch at the bottom of the screen, and one of the colours was significangly off convergence only in the lower left and the top right of the screen. the lower 1/3 of the screen used to shake and have lines running through it....
I thought it was worth a shot at fixing, so i opened it up and replaced the STK392-040's with new ones and checked everything else on the board and made sure any bad looking solder joints were resoldered.
When i turned the TV back on, the bow was gone, the TV looked good, except for the blue convergence which was horizontally off by 10cm (and was at the limits of correcting it).. After a couple of poweroffs and convergence adjustments, the TV instantly developed the bow in the bottom left and shakey lines in the bottom 1/3 which is back to square one!. I quickly felt the heat of the heatsinks and they were both fairly hot, but not to the point of being able to burn my hand or anything like that.
I have since disconnected the board again and double checked resistors, fuses, etc. I dont have access to a scope so i cant see if the generator is sending signals, and im a bit scared to turn the tv set on without the convergence chips installed to check voltages.

Any advice on what to look for to repair the unit or advice would be greatly appreciated. I am able to post a picture as soon as i get home from work if needed.

Also, is there any way to "reset" the TV? or a service menu of some sort - I have searched and could not find any info on how to get into the service menu.

[lcaillo]

Your post was moved to a discrete thread in the proper location to maintain forum organization. Sorry I missed it earlier.

If you had control but the blue was offset, you may have a dc offset at the input to the IC which can cause repeat failures, or, more likely, you missed a resistor problem. Check the dc offset and the resistors with the yokes disconnected and the chips out of the set.

[fire]

Ok, I had a little spare time on the weekend and so I turned the TV on again, and was going through the self check mode (from the service manual – which I bought for $4.95). Everything on the check was ok, but the TV still had the convergence bow in it… I went to the bathroom, and when I returned, the TV was straight again, but the blue offset 10cm to the left as initially reported for approx 1min before it went curvy again. After hours of fiddling, every so often the TV just goes straight for a while.
Anyway, I’ve added some photos in the following microsoft hotmail album for you’s to see with some comments.

http://cid-e167e4c9aedab07d.skydrive.live.com/browse.aspx/TVConvergenceMay09

I have still not checked DC offsets, but will get onto that this week sometime.

Does it sound like the Convergence chips are burnt out again if they keep returning to a decent state every so often? What else could cause this?
by the way, i bought my convergence chips (from bluestar online)

Thanks for any help or guidelines.
Regards,
Tony H

[lcaillo]

Bad connections somewhere, bad ICs, intermittent convergence generator...all guesses until you do some troubleshooting.