Panasonic TNPH0716 repair, anyone know what's wrong?

[johnboy1313]

My folks' TV quit working so they asked me to take a look at it. It's a TH-42PX80U. It'll power on with no blinks. The panel primes but that's it. No response to the remote, no picture or sound. From what I read, the A board, TNPH0716 has failed. It looks like there are multiple repair services available on the net for anywhere from $110 to $160. Usually, when I see repair services, it doesn't take a lot of digging to find a detailed description of the service being done. That isn't the case with this board. I can't find any info. Any of you have any idea where to start checking for failed components? Thanks.

[Locutor13]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Hi, I was able to rescue an A board TNPH0721 of a TH-42PZ80U. Check my thread under the title: Panasonic Viera Plasma TH-C50FD18 2 Blinks error code and picture problem, it might help you as the boards might be pretty similar.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Interesting. C4599 and C4601 both show shorted. Should I pull L4512 and L4513?

[Locutor13]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

I pulled out only the L4512, not sure what will happen if you pull both.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

I pulled L4512. C4599 is still showing shorted. No change in the symptoms except the remote powers on and off. It may have done that before though. I was going off memory when I wrote the original post.

[tom66]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Pull off L4513 too.
Could be bad IC4511, or shorted MLCC C4603.
Does IC4511 get warm/hot?

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Thanks for the input Tom. I'll have to get back to you. I had one of those days at work today, I just laid down on the couch, and I have no intentions of getting up for a while.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

For what it's worth, C4601 is no longer showing shorted.

[Locutor13]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Jhonboy1313, same thing happened to me, the C4599 will stay shorted since the short come from the IC4510 (pulling the L4512 will insulate the C4601 but not the C4599). Sorry it didn't work with you but removing the L4513 might help.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

I reseated the ribbon cables and it's working. I've ordered some ChipQuik and the IC. We'll see how it goes. Locutor13, thanks for pointing me in that direction.

[Locutor13]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Thank you johboy1313, please let us know when you change the IC.

[tw2005]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

I reseated the ribbon cables and it's working. I've ordered some ChipQuik and the IC. We'll see how it goes. Locutor13, thanks for pointing me in that direction.

Any chance we can see some photos of it all at some stage? This is real interesting stuff to follow.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Yes, absolutely. I'm already planning on making a video as well. In the meantime, here's a pic of the inductor I pulled. Its stuck to the end of the tweezers. It's a big one. That's my finger for reference.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Does the inductor have a polarity? I should have marked it prior to pulling it but I forgot. If it gets installed backwards will it cause any problems?

[tom66]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

No polarity for normal inductors. If it is a coupled type (more than two pins) then it might matter.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Thanks Tom. Just waiting on the new chips to arrive.

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

The chip arrived this morning and I quickly went to work replacing it. The old chip came off with no fight whatsoever. The ChipQuik is amazing. I couldn't be happier with it. I wicked all of the pads and the new chip went on without a hitch. I put the board back in and fired it up. HDMIs 2 and 3 both work fine. HDMI 1 doesn't work. I went back and looked at the chip. None of the pins are bridged and all pins are soldered to their appropriate pads. The two caps, C4599 and C4601 are no longer shorted. At this point, I don't know if it's something I did or if HDMI 1 has a separate issue. I wonder if I didn't get that little inductor soldered on correctly, though it appears to be.

Here are the pics from the IC replacement.
https://www.badcaps.net/forum/showthread.php?t=42837

[johnboy1313]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

I checked the inductor and looked at the IC again. I touched up a few pins that looked questionable. Still no HDMI 1.

[tw2005]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

Nice, well you've achieved more than most. I'll have to read your ChipQuik post.

[tom66]

Re: Panasonic TNPH0716 repair, anyone know what's wrong?

From memory, front HDMI has a separate buffer chip which could have also failed...