Panasonic TC-P55UT50 8 blinks

[tech2014]

Hi guys. I have a panasonic plasma tv that has 8 flashes on the LED. I have fixed 2 other TV with exact same problem. Ordering the kit on shop jimmy has always fixed this in the past. Today I had another one. It worked fine after replacing the parts, but it was short lived. After 5 minutes, the tv shut off and the 8 blinks are back again. The parts I replaced are both shorted out again. I even used the screws that came in the package.

The other times I used the kits, they came with an 8 pin IC. I found that TNPA5623AB uses different parts then the TNPA5623. What could cause these parts to blow again. Would it be better to just order a new board or am I missing something?

[nicholas1110]

Re: Panasonic TC-P55UT50 8 blinks

Hi,

Did you reflow the ground pads that arc out near where the screws mount the board? It is nesicary to resolder the ground pads in the top and bottom of the board and also clean the frame of the tv where it has been arcing. The ground arc causes the parts to short in these boards and if the ground is not good and clean it will fail again from a ground arc. The screws with the locking washers are to prevent them from loosening and causing the arcs but it can happen the same if there is not a good ground connection. Hope this helps

[tech2014]

Re: Panasonic TC-P55UT50 8 blinks

thanks. I will do that.

[tw2005]

Re: Panasonic TC-P55UT50 8 blinks

maybe try again and replace the driver IC as well?

[tech2014]

Re: Panasonic TC-P55UT50 8 blinks

Hi tw2005. The board number is TNPA5623. The kit I ordered on shop jimmy only has the diode, mosfet and SMD resistor, no driver IC. I took a pic of the board and it has no IC. The board TNPA5623AB has the IC.

[tw2005]

Re: Panasonic TC-P55UT50 8 blinks

It's the smaller one next to the vacant pad where the other type is. AFAIK they're both driver ICs. Schematic should confirm this IC153(IC16153)

https://www.badcaps.net/forum/showthread.php?t=39142

post #6 although this is AB rev, I'll see if I can work out which number that is. IC501 is wrong ref, that'd be on the Sc board

Just check whats labelled on top of IC153, can't be sure if C0ZBZ0001936 is correct or not and the images i see it looks too big

Drives Q051

[tw2005]

Re: Panasonic TC-P55UT50 8 blinks

https://www.badcaps.net/forum/showth...t=ic153&page=2

That smaller chip looks like it's NJW4840, High Speed Switching Gate Driver. You will know once you look at the numbers stamped on top. Maybe JRC & 4840

https://www.badcaps.net/forum/attach...0&d=1442894057

[tech2014]

Re: Panasonic TC-P55UT50 8 blinks

Yes it does say 4840 JRC on it. I will order this part and replace it along with the diode and transistor. So what about the ground points where the screws go. Can I just remove the solder from the pads and this will fix the arcing issue.

[tw2005]

Re: Panasonic TC-P55UT50 8 blinks

Yes it does say 4840 JRC on it. I will order this part and replace it along with the diode and transistor. So what about the ground points where the screws go. Can I just remove the solder from the pads and this will fix the arcing issue.

well, I'd clean it up , maybe reflow some fresh solder and you could sand or file it so it's reasonably level but if you've replaced the screws that's most of the battle. The solder should squash which is part of the other problem with the wrong screws.

My only experience with this scenario is with a 2011 SC board, same deal loose screws, arcing , blown.

The original screws don't make full contact as the underside is concave.
The solder compresses and I suspect the boards resonate when running plus repeated thermal expansion and contraction eventually work loose or lose contact.

The traditional bolts panasonic have used in the past were a panhead with a spring washer and then a flat washer so even if those pads continue to compress the spring maintains the tension plus most of the older sets I've played with I'm sure I've seen a dab of threadlock(non permanent).

I don't think you've messed up with the screws, it may just need the driver IC as well which I'm thinking you're going to have trouble getting. I did a quick dig and came up empty, not even UTSOURCE.

If that's the case you'd have to get the correct panasonic number and go direct but I'm also thinking why not convert the cct to the other type of driver IC? Looks like it'd be just a drop in and the rest of the cct is already there. The ROHM chip seems easier to get, also looks like it has a thermal ad on it judging by the solder pad on the board.

I don't have enough info on these last models to be sure of that part number .

I have got a P55UT50 manual

It says this has a TXNSS1TFUU = TNPA5623

Shopjimmy has the same data, image of the board matches what you have and the manual.

It has a driver IC at IC153

The part lists IC16153 as C0ZBZ0001936

Same IC is located at IC16130,IC16133,IC16150,IC16503,IC16504,IC16523,IC16524

Checking the images they are all the same IC. So maybe things are just muddied by wrong info in the forums which I may have put up some time ago but I'm seeing a couple of US bucks plus freight. But surely there's a canadian supplier ?

[tech2014]

Re: Panasonic TC-P55UT50 8 blinks

Does anyone know if it would be ok to just remove the original driver IC and put in the newer one.
Im not sure why SJ doesn't include the gate driver IC for the TNPA5623. If I can find it I will replace it.

[tech2014]

Re: Panasonic TC-P55UT50 8 blinks

Does anyone know if this will work?