Panasonic TX-P42X20E

[romulus123]

Hello !

(Sorry for my bad English)

I got a Plasma TV Panasonic TX-P42X20E down.
Error code 4 => SN and SS was shorted.

I replaced:

SS = ----TNPA5072----
Q001, Q002, Q021, Q022: RJP30E4
Q101, Q102: RJK2017
IC131: M81735FP

SN = ----TNPA5066----

D451: D1FK60
D481: FU20TM5S
Q451: DG501RP
Q421: RJP43F4A
Q661: RJP63F3A
Q401, Q402: RJP56F4A
IC773: 5N74AHCIG14DBVR
IC131: M81737FP
Q702: 2PD601 (not shorted)
Q818: 2SK3018
IC521: M81737FP

Upon powering => Click .... Error code 2 !

now,

Q001, Q002, Q021 and Q022 are shorted on the SS board.

And on the SN: Q661 shorted + D641 (which was not shorted before)

I noticed that I had forgot to solder pin 6 (VS) of IC131 (M81735FP) on the SS...

Could it cause damage? Or maybe the panel is shorted?

Any suggestions? Thanks !

[flocko]

Re: Panasonic TX-P42X20E

You will need to recheck all the parts you have replaced . this is what happens If you just miss one thing, you will have more then just Q661 and D641 shorted, thats for sure on the SN. but you would not have damaged the PDP. look back though the old posts from TW and myself for what parts you could have missed (look under TNPA5066). these board can be a real pain to get right but stick at it you were almost there. Flocko

[romulus123]

Re: Panasonic TX-P42X20E

Thank you Flocko

(Small mistake in the first post : I replaced IC773 by a TC7SH14F and D451 by a RF101L4S)

I've read your topic, and also those of TW2005 ... It helped me a lot !

All components seems to be Ok, exept Q001, Q002, Q021, Q022 on the SS and Q661, D641 on the SN.

[flocko]

Re: Panasonic TX-P42X20E

I always use ES1Gs 400v 1A SMD diodes (D451), what we found was if Q661 goes short it was a safe bet IC773 (Schmitt inverter ) would most likely be taken as well, and if IC773 goes it takes Q701/Q702 and so you go round and round. I repaired a TNPA 5062 SC in a 37" set that used TNPA5072 SS and missed a blown driver (M81735FP)on the SS, that took out the SC +SS again , by the time I had the set running again I don't think there was much I had not replace on both boards, almost all the IGBTs and diodes, and SMD parts. so check and check again for the cost of these SMD components always replace them if at all unsure . Good Luck with it Flocko

[romulus123]

Re: Panasonic TX-P42X20E

Hey ! Thank you again.

I will replace Q701 (I had already replaced Q702) Q001, Q002, Q021, Q022, Q661 and D641.

Do you have a method to test the driver M81735FP ? It is not shorted ... (The components are cheap but if they burn out again... it's going to be expensive)

A SS board failure can destroy the SN ... But is that a SN failure can destroy the SS board ?

I remain puzzled about the cause of the destruction of the new transistors ...
If it's just because of a forgotten solder joint on the driver ... "It's boring !"

[flocko]

Re: Panasonic TX-P42X20E

I think I can say yes SN fault will take SS and likewise SS fault will take SN, I don't have a method of testing the driver IC but will always replace if the IGBTs are Short . TW repaired an SS only for it to fail after a week and could only put it down to not replacing the driver IC all four RJP 30E4s blown also did a lot of damage to the SN

[romulus123]

Re: Panasonic TX-P42X20E

Hey !

I have not found other short circuit...

I will replace:

Q001, Q002, Q021, Q022: RJP30E4
IC131 : M81735FP
Q661 : RJP63F3A
D641 : RF2001TM3SW
Q701 : MMBTA92 (not shorted)

No other opinions before ordering ?

[tw2005]

Re: Panasonic TX-P42X20E

Hey !

I have not found other short circuit...

I will replace:

Q001, Q002, Q021, Q022: RJP30E4
IC131 : M81735FP
Q661 : RJP63F3A
D641 : RF2001TM3SW
Q701 : MMBTA92 (not shorted)

No other opinions before ordering ?

A shorted Q661 , Q701, D641 and nothing else would be rare I would think. was this just a continuity checkor did you measure resistance to? My meter quits around 100ohms for a beep but things can still blow and have a few hundred ohms instead of K or M ohms . Did you check SMD diodes too especially around the DG501 energy recovery section that connects to the SS.

Can't say this model was as easy or fun as the FHD 5081 board. I had a few problems, still have my blown SN still from the SS dying . When one board can kill the other, I know my patience ran thin which is why I've avoided messing again now that it's been running good for ages now.

[flocko]

Re: Panasonic TX-P42X20E

I am with TW if you can only find Q661+D641 short you have got away very lightly, we were never that lucky? you will soon know if you have missed something ,best to have another check just in case, but for sure replacing the IGBTs and Driver should clear the SS board, not to sure about the SN .but check your soldering ,have had tales of lots of dry solder tabs on SMD IGBTs that prevent boards from working (and blowing ). but as said before good luck and let us know how it goes Flocko

[romulus123]

Re: Panasonic TX-P42X20E

Thank you a lot !

I'll test the components, again and again...
Indeed (and happily) SN is not too damaged, the first time it seems that D641 was not short circuit ... I do not understand why Q661 + D641 are dead now...

I obtained values ranging from kilo-ohm to mega-ohm between each leg of all the transistors and diodes (exept Q661 and D641).

IC773 seems ok, the voltage regulator IC771 and IC724 works.

No short-circuit around the Q451 (DG501RP).

To terminal block SN2: 17.5m
To terminal block SN3: 105k

[romulus123]

Re: Panasonic TX-P42X20E

Hello,

I am back !

I replaced the dead components ...

Test without SN: 8 blinks => OK
Test without SS: 6 blinks => OK

I reconnected everything => PAF! 2 blinks

Q021, Q022, Q451, Q421, Q401, Q402 and Q661 are dead !!!!!

thank you again...

[flocko]

Re: Panasonic TX-P42X20E

testing with good boards the way you have is not a good way to go . with just the SN board fitted and no SS . there would be no energy recovery and that in its self could damage them, but you are now on the merry go round and were it stops nobody knows ? look out for TW I think he is still on there with his TNPA5066. start testing and rebuild Flocko