Panasonic TH-50xp80u power supply

[tmedley]

I inherited a TH-50xp80u from a friend at work. It had quit on him and he wanted another friend to fix it for him. This begins the problems for me. His friend has butchered the power supply board and now it is missing a few components. Mainly the c558 and c559 caps. Does anyone know what values these caps should be?

He also removed the fuses and one of the relays and the two large caps. He resoldered some of the components with really cold joints and missed one leg on the relay entirely. I have been surching for a new board but I can't seem to find one with the same part # available.


Thanks for any help.

[start2011]

Re: Panasonic TH-50xp80u power supply

I inherited a TH-50xp80u from a friend at work. It had quit on him and he wanted another friend to fix it for him. This begins the problems for me. His friend has butchered the power supply board and now it is missing a few components. Mainly the c558 and c559 caps. Does anyone know what values these caps should be?

He also removed the fuses and one of the relays and the two large caps. He resoldered some of the components with really cold joints and missed one leg on the relay entirely. I have been surching for a new board but I can't seem to find one with the same part # available.


Thanks for any help.

I have Panasonic TH-50PX80U ( not TH-50XP80U ). I could not find C558 and C559 in power supply board.https://www.badcaps.net/forum/attach...1&d=1329283189

[tmedley]

Re: Panasonic TH-50xp80u power supply

You are right I transposed the px sorry.

Your power supply is different then mine. Mine is the LSEP1260 style from what I can tell searching the web.

I found one on ebay that says its for the TH-42PX80U but I am not sure that it will work in the 50". I would wager that it would, but that would be a $100 wager that I might lose.

Thanks for looking at yours for me. I appreciate you doing that for me.

[tmedley]

Re: Panasonic TH-50xp80u power supply

I have found the value of the caps that are missing and I have those in stock.

There is a large sized capacitor that is a 1900uf 220v nichicon that has a bulged top that I would also like to replace. Mouser doesn't show a listing for a solder in pin type cap that size, any other sources I should look at?

[tom66]

Re: Panasonic TH-50xp80u power supply

I have found the value of the caps that are missing and I have those in stock.

There is a large sized capacitor that is a 1900uf 220v nichicon that has a bulged top that I would also like to replace. Mouser doesn't show a listing for a solder in pin type cap that size, any other sources I should look at?

Are you sure it is bulged? Those rarely fail. The closest is 1800uF, or 2200uF. Going up should be fine.

[tmedley]

Re: Panasonic TH-50xp80u power supply

it is bulged but not a lot. Compared to the other 440uf of the same size it is definitely bulged. I may just resolder his poor connections and see where it gets me. I have ordered the missing fuses and a new power mosfet that is known to go bad on these boards. I will replace these and the missing capacitors and resolder all the joints and hope the large caps are ok. At least then maybe I can get the tv to self test.

[tmedley]

Re: Panasonic TH-50xp80u power supply

I reinstalled the missing components and tested the board. I now have a working power supply board.

However, now I am back to the problem that the original owner first described it having before the "other guy" tried working on it. It has a back lit black screen and a red power light with no blinks. I am thinking it is the "A" board from what I can read from the service manual.

Anybody have any input here?

[tom66]

Re: Panasonic TH-50xp80u power supply

I reinstalled the missing components and tested the board. I now have a working power supply board.

However, now I am back to the problem that the original owner first described it having before the "other guy" tried working on it. It has a back lit black screen and a red power light with no blinks. I am thinking it is the "A" board from what I can read from the service manual.

Anybody have any input here?

Do you get any sound?

If you use the remote, do you get a user interface, or flashing from the LED?

[tmedley]

Re: Panasonic TH-50xp80u power supply

Do you get any sound?

If you use the remote, do you get a user interface, or flashing from the LED?

No sound. No remote response of any kind. I just have the clicking of the relays and the red digital out lights up, but they never go back off. Pushing the power button has no response unless you hold it in for several seconds then it turns off and right back on.

No blinking codes, just a solid red light. The screen is lit, but black.

[tom66]

Re: Panasonic TH-50xp80u power supply

No sound. No remote response of any kind. I just have the clicking of the relays and the red digital out lights up, but they never go back off. Pushing the power button has no response unless you hold it in for several seconds then it turns off and right back on.

No blinking codes, just a solid red light. The screen is lit, but black.

What does the service manual say? Have you checked for a good +15V supply? (IIRC, Panasonic PSUs generate a fixed 15V output and then step this down for the other rails.)

[tmedley]

Re: Panasonic TH-50xp80u power supply

What does the service manual say? Have you checked for a good +15V supply? (IIRC, Panasonic PSUs generate a fixed 15V output and then step this down for the other rails.)

Manual says the board should output 15v to the A board, and it does. And the led indicators on the other boards are lit. If you follow the diag the P board pushes 12v to the SS board then returns to the P to create 5v to the A which returns a 2.7v/3.3v to the P to turn on the f+15v circuit to the A.

Now I should have 10 blinks if one of those is not present. I have all of those present so I have no blinking light. But I also have no "power on". It is in STBY all the time.

Diag sheet says it should click the relays and light up the optical out light for 15seconds then they should click off and light should go out until unit is turned on. My problem seems to be that they never turn off and the light never goes out. It is as if it is doing a self check and not completing the check.

[tom66]

Re: Panasonic TH-50xp80u power supply

Manual says the board should output 15v to the A board, and it does. And the led indicators on the other boards are lit. If you follow the diag the P board pushes 12v to the SS board then returns to the P to create 5v to the A which returns a 2.7v/3.3v to the P to turn on the f+15v circuit to the A.

Now I should have 10 blinks if one of those is not present. I have all of those present so I have no blinking light. But I also have no "power on". It is in STBY all the time.

Diag sheet says it should click the relays and light up the optical out light for 15seconds then they should click off and light should go out until unit is turned on. My problem seems to be that they never turn off and the light never goes out. It is as if it is doing a self check and not completing the check.

So it definitely seems like you have an A board problem. Are there any fuses on the board? Checked the voltage regulators? What about diodes for the buck converters, if any, on the A board?

[tmedley]

Re: Panasonic TH-50xp80u power supply

So it definitely seems like you have an A board problem. Are there any fuses on the board? Checked the voltage regulators? What about diodes for the buck converters, if any, on the A board?

No fuses that I see. I will check the regulators and diodes tonight.

The manual asks you to check 4 fuses in the diags, but I can only find 3 and they are on the power supply or P board. Anybody know where the elusive 4th fuse is?

[cmj21973]

Re: Panasonic TH-50xp80u power supply

Need larger picture of power supply, front and back.

[tmedley]

Re: Panasonic TH-50xp80u power supply

I have found the problem on the A board. An IC with a burn spot and a bulged out side. The numbers on the IC are 529GL128N90TFIR2 and 823FVK52 S and the name spanion on it. Anyone know what a replacement IC might be for this part?

[tom66]

Re: Panasonic TH-50xp80u power supply

I have found the problem on the A board. An IC with a burn spot and a bulged out side. The numbers on the IC are 529GL128N90TFIR2 and 823FVK52 S and the name spanion on it. Anyone know what a replacement IC might be for this part?

I think you mean Spansion.

Unfortunately, Spansion make flash memory; that chip likely carried the firmware for the TV. If that's damaged, even a replacement won't work because the firmware won't be there. So you would need a new A board.

Can you post a picture? Because I've seen a couple of RAM and flash chips that looked damaged (with a hot spot in the middle, where the label had worn down) but were not actually damaged.

[tmedley]

Re: Panasonic TH-50xp80u power supply

I think you mean Spansion.

Unfortunately, Spansion make flash memory; that chip likely carried the firmware for the TV. If that's damaged, even a replacement won't work because the firmware won't be there. So you would need a new A board.

Can you post a picture? Because I've seen a couple of RAM and flash chips that looked damaged (with a hot spot in the middle, where the label had worn down) but were not actually damaged.

yeah Spansion, sorry missed and s there.

I ordered a new A board online from a place called All pro TV. Hopefully it will fix the tv and thats all thats bad. Guess I will find out when the board shows up.

here is a pic of the ic. If you look closely you can see where the ic is bulging something out of its side.

[tom66]

Re: Panasonic TH-50xp80u power supply

yeah Spansion, sorry missed and s there.

I ordered a new A board online from a place called All pro TV. Hopefully it will fix the tv and thats all thats bad. Guess I will find out when the board shows up.

here is a pic of the ic. If you look closely you can see where the ic is bulging something out of its side.

That chip isn't failed. The mark looks like a fingerprint or smudge.

[tmedley]

Re: Panasonic TH-50xp80u power supply

It's not a smudge because it won't wipe off.

I recieved my new "used" A board and installed it. With mixed results. I can now power the tv on and off. However, I still have to picture and the light still doesn't blink. It does do its power relays up and turn them off 15sec later like it was supposed to do with the bad board but wouldn't. I can trick it into flashing codes, which I could never get the last board to do.

So why do I still have no picture? No menus, no nothing, just a big lit up screen with nothing on it.

All my voltages are correct going to and returning to the power supply. The 15v, 12v, 5v, and 3.2v are all there.

Anybody know what the voltages are supposed to be at the p2 and p11 connectors? I have 185v.

[tmedley]

Re: Panasonic TH-50xp80u power supply

I downloaded the manual for the px80ua which is what I have. I have checked every voltage on every board test point. They are all dead on. I still just have a blank screen with no pic or sound and no on screen display for menus. I have noticed if it is left on for a while the tv cycles itself off then on. Sometimes off and I have to turn it back on.

Is this an SS board problem.

Any suggestions at all. When I did the SS board seperation test I at least had snow on the screen. lol.