Panasonic TH-P42A2G SN Board Problem 4 blinks

[heri]

Re: Panasonic TH-P42A2G SN Board Problem 4 blinks

So on the board location for this opto, what's the resisitance between pin 5 & 8? Is it the same 50ohms?

its same 50 ohms.

Hope you realise the original Q701 & 702 are 2PD601ART and MMBTA92 respectively.
That would mean your MMBT3904 is about 20V underspec and your MMBT3906(40V 0.2A, PNP) is about 260 volts under rated as the MMBTA92 is a 300V 0.5A PNP

I see thats why my replacement short again..
Only these 2 transistor Q701 & Q702 I have replace..will then search other replacement as its specification.

[tw2005]

Re: Panasonic TH-P42A2G SN Board Problem 4 blinks

Only these 2 transistor Q701 & Q702 I have replace.



I see thats why my replacement short again..
will then search other replacement as its specification.

I would say so but there's a lot of variables at play here, you could be fighting a tough battle because partial or incorrect repair can cause more damage and make it very hard to fix.

You also need to sort out that 50 ohm reading

[tw2005]

Re: Panasonic TH-P42A2G SN Board Problem 4 blinks

its same 50 ohms.



I see thats why my replacement short again..
Only these 2 transistor Q701 & Q702 I have replace..will then search other replacement as its specification.

Then you need to find what's shorted. You have 2 choices, IC773 or IC771. Process of elimination. So remove one.

Correct resistance in cct would be very close to 6 Kohms across pin 5 & 8

Are you saying only Q701 & 702 have been replaced on this board, nothing else?

[heri]

Re: Panasonic TH-P42A2G SN Board Problem 4 blinks

I have replace these:

>> 1st:
Q661 - 30F125
D641 - RF2001
Q402 - RJP63F4A
Q401,Q621 - RJP56F4A
Q421 - RJP43F4A
Q441 - DG501LW
Q451 - DG501RP
(bought from utsource.net)

when I turn on TV then Q401 & Q661 shorted.

>> 2nd:
Q401 - 30J124
Q661 - 30J124
Q701 - MMBT3904
Q702 - MMBT3906
(from local supply)

attach bulb 100W/220V across SN2-P2 for safety.
when turn on TV again then Q701, Q702 shorted, also found that IC461 (opto) is broken.

[tw2005]

Re: Panasonic TH-P42A2G SN Board Problem 4 blinks

I have replace these:

>> 1st:
Q661 - 30F125
D641 - RF2001
Q402 - RJP63F4A
Q401,Q621 - RJP56F4A
Q421 - RJP43F4A
Q441 - DG501LW
Q451 - DG501RP
(bought from utsource.net)

when I turn on TV then Q401 & Q661 shorted.

>> 2nd:
Q401 - 30J124
Q661 - 30J124
Q701 - MMBT3904
Q702 - MMBT3906
(from local supply)

attach bulb 100W/220V across SN2-P2 for safety.
when turn on TV again then Q701, Q702 shorted, also found that IC461 (opto) is broken.

Q661 - 30F125 This should be RJP63F3A
D641 - RF2001what numbers after this? they dictate what voltage as there are several RF2001 versions
Q402 - RJP63F4A Q401 & 402 are the same transistor RJP56F4A
Q401,Q621 - RJP56F4A Q621 is a 30F125
Q421 - RJP43F4A correct
Q441 - DG501LWcorrect
Q451 - DG501RPcorrect

30J124 is a 600V IGBT but only 30A.

RJP63F3 is 40A and RJP56F4A I believe is 40A.