panasonic tx-p50s10b buffer woes

[steviewonder]

Hello once more!
Another tale of woe,i will start at the beginning.
Bought the above tv from a elderly gentleman on ebay,who said it wouldn't turn on one morning,with 7 red blinks.
On arrival home,deduced the top buffer had failed.
Replaced this,all was well,then sold it to the next door neighbour.
Two weeks later,same problem.thought just bad luck with the second hand one,so replaced it again.
All was going well,so replaced the back,switched it on again...and 7 more blinks.
At this point i will refrain from mentioning the language uttered...
So a check with all three top buffer reveals the second chip down has failed on all three,would i be correct in thinking the screen has some kind of issue,or more likely the ysus has a issue?
Failure only seems to happen at power up..
Anyone's thoughts most welcome!

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

Hmm possibly wait for Tom66 to chime in he will probably know the exact failure here. Have you checked that all voltages are inspec and not to high ? If I recall these have the Tcon inter- grated on to the mainboard ?

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

yes,,all voltages present and correct.Haven't noticed if the Tcon is integrated with the mainboard-will have a look at that a little later..Sounds a curious arrangement!

[awyatt2]

Re: panasonic tx-p50s10b buffer woes

may be sustain board something bad on the line?

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

Yes,quite right reecyburger,integrated control with the main.
wondering if there could be a glitch in the firmware causing buffer failure?.
Unlikely,i know, but a recent samsung ps43D450 i had was randomly blowing the fets on the xsus because of firmware...
Odd it's the same ic that fails,would rather repair the ysus (tnpa4829 AC) if it's that,but where to start?..and could quickly end up with a mountain of duff upper
buffer boards on the way ..

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

I actually recently repaired on of these mainboards I had to reflow it, the Hdmi video processor was at fault with failed Bga solder causing 14 blinks. Maybe your processor could be at fault over driving something. I will link my thread.

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

Its something intermittent as if it was a Sc fault the buffer would probably blow instantly.
Here is my thread:
https://www.badcaps.net/forum/showthread.php?t=49721

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

Interesting thread,will apply some heatsinks there I think.
Odd that it works flawlessly,but eats the same ic on the upper,at switch on.it's hit and miss
on wether the same chip fails-or not at switch on.i see this is going to be a real pain!

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

Also could you check something for me Steve ? When the set is working how hot does that Hdmi chip get mine gets very hot to the point where I couldn't keep my finger on it thats why I heatsinked it, Im not sure its abnormal. Cheers.

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

If you do decide to try a reflow only use hot air dont put it in an oven lol, but before you try a new buffer lets wait and see what some other people think.

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

yes,will let you know tonight on that reece,hopefully.just going to have a bash at replacing the s/c buffer ic.Wonder why all manufacturers go nuts with the silicone rubber on them?...it doesn't seem to serve any purpose!
cheers,Steve.

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

Cheers Stevie I will also link another thread where I provided some instructions on replacing a Scan Ic one min.

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

Here you go I gave some instructions on replacing the scan Ics scroll to the bottom:

https://www.badcaps.net/forum/showthread.php?t=49748

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

yes,slightly different to my usual approach.I usually cut the pins off the i.c all the way round,then pencil torch the ic away from it's soldered pad,then wick the pins off..quite easy
so long as you have super eyesight close-up,a fine iron and a steady hand!...will let you know how it goes!

[flocko]

Re: panasonic tx-p50s10b buffer woes

Could be Sc faulty? have you tried the Sc board with the buffers disconnected and SC50 shorted, this will show you if the Sc board is at fault, if the 7 blinks stops and get a green LED

[steviewonder]

Re: panasonic tx-p50s10b buffer woes

Hi flocko,yes that was my first step in diagnosis,all was good.I so hate plasmas at times!...it appears that for some reason,the i.c that drives SU2 connector is failing repeatedly,but randomly,and only at power on..might end up having to replace the ss board,but are pricey,and may have some other cause.Could be a money pit this one!

[ReeceyBurger123]

Re: panasonic tx-p50s10b buffer woes

These have a cracking image when they work though, however difficult to repair as they are built fairly well.

[freakaftr8]

Re: panasonic tx-p50s10b buffer woes

Just a thought but could buffer scan voltages be working out of spec?

[flocko]

Re: panasonic tx-p50s10b buffer woes

Hi check Q660 on the Sc board if this is short this will take out buffer ICs and I dont think will give a blink code with Sc50 shorted and buffers disconnected