Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ700U

[retiredcaps]

Just saw this 15 minute video on gavincurtis's channel.

http://www.youtube.com/watch?v=qQ_iL...1&feature=plcp

Basically, for some Panasonic plasma TVs, there is a thermal fuse inside the secondary winding on one of the transformers. That fuse goes open and obviously the TV doesn't work. He shows this starting at the 5 minute mark.

Now I have ZERO experience fixing plasmas and know only what I read here, but I haven't seen any case yet where there was a thermal fuse inside a transformer?? Or have I not been paying close attention?

[tom66]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

Interesting. I've repaired a TH-42PZ80BA with a power board that looks the same to that, so I expect it would apply to that too.

[mockingbird]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

I'm watching his CS80 videos. Fascinating. What an impressive synthesizer. Unfortunately, no one uses synthesizers well in music nowadays. Why does he always use GP capacitors (albeit Panasonic) though?

[randtek]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

In the last 20 years or so, I have occasionally found transformers that were internally fused. I learned about them years ago at a school on VCRs, I don't remember which manufcaturer. It seems like a generally bad idea to me though.

[PlainBill]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

I have mixed feelings about this video. Obviously, identifying the nature of a failure is always a positive. It would be nice to know what the underlying cause was. Given that Gavin Curtis reported that essentially new power supplies (removed from TVs with screens damaged in shipping), it would appear the core of the transformer was inadequate. I was impressed with the detail he went into on the nature of the failure, and the parts requires for the repair. His use of an underrated thermal fuse would reduce the chance of overheating. The detailed instructions for disassembly were impressive.

I was less than impressed with other parts. His explanation of the purpose of a PRC front end was laughable (or course, the purpose of the PFC front end is pretty laughable). The repair technique had a number of flaws. Needle nose pliers will make an adequate heat sink for soldering wires to the leads and assure better contact than crimp terminals. The wires themselves should have been anchored in place.

PlainBill

[Tuberon]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

Interesting. I've repaired a TH-42PZ80BA with a power board that looks the same to that, so I expect it would apply to that too.

Hi Tom 66 - I have a Panasonic TH-42PZ80BA bought in Dec 08 which has been absolutely fine for the past 3 years but has now developed the blinking problem and will not turn on. It blinks red twice then pauses and then repeats. It's been like this a few weeks making it difficult to turn on from fresh start but now it's not turning on altogether and been out of use for the past few days. When we try turn on we get click green flashing then click and off, back to double red flash, pause etc. As you've fixed one of these exact TV's can you (or anyone else maybe) please give me an idea where the problem might lie e.g. xsus board, buffer board...?

[tom66]

Re: Youtube-How to Repair a PANASONIC Plasma TV with Blinking LED TH-42PZ77U TH-42PZ7

Hi Tom 66 - I have a Panasonic TH-42PZ80BA bought in Dec 08 which has been absolutely fine for the past 3 years but has now developed the blinking problem and will not turn on. It blinks red twice then pauses and then repeats. It's been like this a few weeks making it difficult to turn on from fresh start but now it's not turning on altogether and been out of use for the past few days. When we try turn on we get click green flashing then click and off, back to double red flash, pause etc. As you've fixed one of these exact TV's can you (or anyone else maybe) please give me an idea where the problem might lie e.g. xsus board, buffer board...?

Well, you'd be best creating a new thread - then start with posting pictures of the inside of your TV.

Getting worse slowly sounds like bad capacitors but these Panasonics are very over-engineered, which is nice. They are usually full of high quality capacitors, Rubycon, Panasonic (who make their own capacitors), Nichicon and Chemicon. It could also be a bad solder joint.

The service manual is here:

2 blinks indicates "15V SOS" which means the problem is likely on the power board. If I recall correctly, the power (P) board generates a stable 15V, which is then stepped down to 3.3V & 5V by the PA(?) board, so the problem is most likely on the P board.