TC-P50S30 TNPA5351 has failed twice in three days.

[johnboy1313]

I repaired this set a few weeks ago by replacing three 30f131 fets and sold it. After three weeks, it quit again. I opened it up and found the same three fets were shorted. I replaced them again and this time, used screws from an older Panasonic with lock washers when installing the SC. The owner picked it up around 9:00 last night. At 10:00 last night, I got a text saying it had blown again.

Any guesses as to what I could be missing?

[tw2005]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

I repaired this set a few weeks ago by replacing three 30f131 fets and sold it. After three weeks, it quit again. I opened it up and found the same three fets were shorted. I replaced them again and this time, used screws from an older Panasonic with lock washers when installing the SC. The owner picked it up around 9:00 last night. At 10:00 last night, I got a text saying it had blown again.

Any guesses as to what I could be missing?

I don't have any great suggestions but which 3?

The One I did needed 4 30F131. Q402,403,422,423

[martino]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Replace all 4 : Q402,403,422,423 and also D401,421. And measure R402,403,422,423. Can't remember ohms on those but compare the 4 to each other?

Edit: lol @ TW2005,you beat me to it again,haha

[ReeceyBurger123]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

All solder the SC power wires directly to the Pcb after replacing all 4 again.

[tom66]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

All solder the SC power wires directly to the Pcb after replacing all 4 again.

Why?

[johnboy1313]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

I don't have any great suggestions but which 3?

The One I did needed 4 30F131. Q402,403,422,423

If I remember correctly, if you are looking at the board, installed in the TV, it was the row of fets closest to the connector. The bottom one, the next one up, and the first one above the two diodes. I don't remember their location names.

[ReeceyBurger123]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Why?

Check Ali E's thread about possibly causes of failure for these and other S/C boards.

[tom66]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

If I remember correctly, if you are looking at the board, installed in the TV, it was the row of fets closest to the connector. The bottom one, the next one up, and the first one above the two diodes. I don't remember their location names.

You should always replace the transistors in the lower half when replacing the upper half.

[Alastair E]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Why?

Because I killed an SC in a 42" by merely Touching the cables and causing the (cruddy) two-pin plug to arc...

I solder directly all Panasonic SC and SS boards power-supply cables now, Both Ends ...

[HI-ZEES]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

hello good day every one am new, don't really know where and how to post here but i would appreciate if someone will guide me.

here is my challenge
my hp elitebook 8440p core i5 flashes power light 8 times but refuses to on have tried doing a lot of troubleshooting like ready IC, capacitors, charging charger, memory etc. but still will not on. pls i need help

[dick_barton]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

here is my challenge
my hp elitebook 8440p core i5 flashes power light 8 times but refuses to on have tried doing a lot of troubleshooting like ready IC, capacitors, charging charger, memory etc. but still will not on. pls i need help

I think you have messaged the wrong forum.

[ReeceyBurger123]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Also doubt its a transistor fault, even if one was leaky they would blow instantly so something eles must be blowing them.

[tom66]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Because I killed an SC in a 42" by merely Touching the cables and causing the (cruddy) two-pin plug to arc...

I solder directly all Panasonic SC and SS boards power-supply cables now, Both Ends ...

Hm, I always thought the connectors were decent - perhaps the contacts were worn from previous arcing events or something of that sort.

[tom66]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Also doubt its a transistor fault, even if one was leaky they would blow instantly so something eles must be blowing them.

This isn't necessarily true as it's more than possible that a transistor could be wounded early on and then fail later. The energy dumped into it by a short circuit could cause damage to the die that may not show up on any tests except by using an electron microscope - so *always* replace the other transistor in any half-bridge.

[johnboy1313]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Already ordered the kit. I'll replace all four fets, and the two diodes and probably the four resistors as well.

[tw2005]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

yeah , I'd do the 4 like Tom suggests. That's the same banks I replaced but did the 4 and I also used FGD4536 which are smaller package Dpak and it's been good for 18 months now.

[johnboy1313]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Got the kit in yesterday and installed the whole 13 piece kit this evening. I even soldered the cables on both the SS and the SC. it just popped again. Time to part this one out. I'm done.

[tw2005]

Re: TC-P50S30 TNPA5351 has failed twice in three days.

Tragic. Economic loss . It would bug me not knowing the cause. Thankfully the wins outweigh the losses. Know the feeling. I'm on day 4 on a 4782 . No worky no smoke 7 blink