panasonic tx-p42gt30b

[Alastair E]

Re: panasonic tx-p42gt30b

Aye--Check Bridge-rec and the MOSFETS....

[Jahson]

Re: panasonic tx-p42gt30b

Those meter readings are from the bridge rectifers in post #34

[Jahson]

Re: panasonic tx-p42gt30b

Will have look at this set today again?

[Sathhin]

Re: panasonic tx-p42gt30b

I've just got one of these in myself with nearly exactly the same issue. The problem I found is the two FETS under the heatsink near the blown fuse will be short circuit. Q300 & Q301

These guys do a repair kit http://www.ebay.co.uk/itm/PANASONIC-...-/151415201597 although I'll be sourcing my own parts, I'm a little concerned where they mention about a short in the panel? Anyone know what they mean?

Thought this info might help you

[Jahson]

Re: panasonic tx-p42gt30b

where can I get the fuse end holders from pictured here
http://www.ebay.co.uk/itm/PANASONIC-...-/151415201597.

[Jahson]

Re: panasonic tx-p42gt30b

Or the correct name for them?

[tom66]

Re: panasonic tx-p42gt30b

I'm not a fan of that solution. I would use a fuse with leads pre-formed. That looks like it could just come loose. They are available on Farnell and CPC: search leaded fuse, 6.3mm x 20mm.

[Jahson]

Re: panasonic tx-p42gt30b

cheers tom66, could use a bit of solder.

[tom66]

Re: panasonic tx-p42gt30b

Most fuses won't accept solder. The caps are usually plated.

[Jahson]

Re: panasonic tx-p42gt30b

These are open circuit part number is T3D 0D if correct, the last D is underlined.
.
Location D204-D216

[Jahson]

Re: panasonic tx-p42gt30b

http://www.donberg.ie/catalogue/semi...t-tc/t_3d.html
33 euro$

[vinceroger69]

Re: panasonic tx-p42gt30b

these may not be faulty please see
https://www.badcaps.net/forum/showthread.php?t=23214

[Jahson]

Re: panasonic tx-p42gt30b

Cheers vinceroger69, I put them back in then, will start looking at components under the heatshields.

[tw2005]

Re: panasonic tx-p42gt30b

These are open circuit part number is T3D 0D if correct, the last D is underlined.
.
Location D204-D216

yeah, they are not normal diodes, and most people think they are faulty when they test them.

[Jahson]

Re: panasonic tx-p42gt30b

cheers lads, thank the lord I don't have to replace them 33 euros each?

[tom66]

Re: panasonic tx-p42gt30b

cheers lads, thank the lord I don't have to replace them 33 euros each?

Panasonic originals bound to be overpriced. They would cost 50 cents from a good electronic part distributor. But, you need specifications to be sure which part to get.

[guando21]

Re: panasonic tx-p42gt30b

I realise this is an old thread but just wanted to check if the issue was ever resolved? I have a TX-P42ST30b with a similar problem. Started with a 7 blink code, replaced the usualy suspects on the TNPA5330 SC board. On the TNPA5390 P board the 4 amp fuse was blown, replaced it temporarily with a slightly higer rated one as it was all I had to hand (6A or 8A I think?) and it immediately blew again and one of the FETs under the heatsink (Q300) blew as well as the two 8A fuses near the bottom of the board.

Replaced Q300 and Q301 (R6015ANX), replaced all fuses (with correct rating, slow blow fuses), R100 was open so replaced it. When I connected it up the green light starts flashing as usual but when it reached the power on state the 4A fuse blows and it shorted Q300 and Q301 again (these came from RS so should have been decent quality).

Anyone have any ideas where to look next?

[Alastair E]

Re: panasonic tx-p42gt30b

I would check the SS and SC boards again for shorts--It may have shorted on one of those--then killed the PSU again.

When trying next time, wire a 250W lamp, (Or enough bulbs in parallel to make 250-300W) in place of the mains-fuse--may save some silicon if it decides to not work...

[guando21]

Re: panasonic tx-p42gt30b

I would check the SS and SC boards again for shorts--It may have shorted on one of those--then killed the PSU again.

When trying next time, wire a 250W lamp, (Or enough bulbs in parallel to make 250-300W) in place of the mains-fuse--may save some silicon if it decides to not work...

Thanks for the quick reply, I need to wait for more R6015 FETs to arrive so I'll check everything again. Regarding the lamp current limiter, would something like this do the trick? https://www.youtube.com/watch?v=UCtzZl5ZcHo

[chrismurphy]

Re: panasonic tx-p42gt30b

Sorry to say this ,but your knowledge is not good enough to diagnose the problems
Buy a replacement board