Re: Panasonic TX-P42ST30 with exploding diodes....
Found a defective board for the customer so thats good. Still wondering what is causing the diodes to blow this hard.....
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Re: Panasonic TX-P42ST30 with exploding diodes....
Well yes but not in this case.
The standard 6 IGBT's were shorted. Q421 , 422 , 423 and the 3 above the big capacitors next to the RF1510 diode.
I did not get a bang after replacing the fets , i got 6 blinks. This is a standard situation as i also had it on the repair i did AFTER this board. Replaced the 2 parts and the bangs came...
I left the board as is and started with the other tv. Same board same tv and same parts and this board turned on! Only difference with this board is that i rechecked all IGBT's before i soldered them on , again i took the FGD4536TM from mouser. ( They don't work on the other bad board ).
Im hoping Flocko or TW2005 have seen this fault before or know whats causing this but my personal feeling is that i need to replace almost ALL parts in that circuit.
Possible solution:
Replace all parts in picture 2 + diodes 430 , 432 and 433 + resistors?Last edited by Moreno83; 10-20-2016, 01:41 PM.Leave a comment:
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Re: Panasonic TX-P42ST30 with exploding diodes....
Aye--But IF you didnt replace ALL these parts At The Same Time--One will kill another....
What IGBT's were faulty when you FIRST had the set?Leave a comment:
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Re: Panasonic TX-P42ST30 with exploding diodes....
I first got 6 blinks. I then replaced IC502 and Q531 and the diodes on top exploded.
The fets q421/422/423 were shorted again. Replaced them with original panasonic parts. Replaced all diodes and resistors + blue ceramic caps and again all popped.
Did not replace other driver ic's besides IC502.Leave a comment:
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Re: Panasonic TX-P42ST30 with exploding diodes....
Did you replace both the transistor driver pairs as well as the little buffer chips that drive each set of IGBT's?
--They ALL should be changed in one hit or there'll be probable troubles...Leave a comment:
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Re: Panasonic TX-P42ST30 with exploding diodes....
Photo with the diodes that are still fine is from the board with the bad buffers.
Other photo's are from the blown board.Leave a comment:
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Panasonic TX-P42ST30 with exploding diodes....
Hey guys ,
Im having some big troubles with a TNPA5330 AB board. It's a tv from a customer.
It had the usual 7 blinks and the buffers are all ok! Replaced the 6 shorted fets , turned on the tv and i now got 6 blinks.
I then replaced the 2 small ic's and i got some loud bangs above the white prong connector.
I think that there are also FAKE FGD4536TM igbt's. I got a few from mouser and a few from china.
The ones from mouser got a cut on both corners showing the copper , the ones from china dont have that.....
Anyways to continue the story. The diodes 430 , 432 and 433 were shorted and even popped! Im not sure if this is caused by 1 fake igbt or does the board have a different problem?
Both resistors are bad also!
I replaced the resistors and diodes + shorted fets 3 times now and again the diodes explode.
I even replaced the 4536TM for original rjp30h2a and still the diodes blow. The fets in the bank measure 90ohm after the bang....
Also , when i measure the resistor on the good board it measures 45k. When i put the good resistor on the bad board it goes to 35K...so something is pulling the resistance down.
Something in the energy recovery circuit is blowing up my board.... i got to watch out now as the traces are getting black/broken because of the bangs.
Any idea's what is causing this?
I got a board with a shorted buffer so i can replace parts.....
Ps , repaired the same model for different customer and that went fine!!
Thanks!Attached Files -
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I bought faulty speakers, M-Audio AV40's. Other speaker has all the electronics in it and the other speaker is just passive one powered by the other speaker's amp. Original problem with the speakers was loud buzzing. I figured out that there is something wrong with the capacitors. I went ahead and replaced every electrolytic capacitor on the PCB. The caps are good quality and have the same values as the original ones.
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Dear members,
I have a linear variable power supply with unknown brand name that I used for voltage injection.
Then it failed. I discovered that its transistors (Q1 and Q2) are shorted.
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I can replace the burned transistors.
But I do not know the model of the zener diodes. the model number is not marked on the zener diodes.
Therefore, I cannot replace the zener diodes.
I do not want to test the zener diodes in a test circuit to discover their model or value.
no schematics are available... -
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Ok Im a mechanical engineer ...but I thought I was able to follow a rather simple flowchart for electric troubleshooting 😂.
TV Model: Panasonic TC-P55ST50
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Thanks in advance!...
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