TC-P42C2 - Need advice

[fyca]

I will start at the beginning. I acquired this TV from a friend who said it no longer worked. Being technologically inclined I plugged it in to observe what its problem was. It turned on and displayed but it was not displaying a clear picture, rather just distortion, but when I pressed the menu button I could see parts of it on the screen. So I figured it would be an easy fix, after looking through all the forums here on BadCaps and AVS I did a couple of the tests and figured it was probably the P board. After a couple of weeks my brother came over and wanted to see what was wrong with it and out of no where it was working with no visual problems, then after about 15 mins the video started to fade out to what it was doing originally, then it finally turned off to 7 Blink SOS. After looking through the forums again I found a procedure that said to disconnect SN20 and SN2 and if the blinks changed to 6 it indicated that the SN was bad so I ordered a new SN board - Original board had number TNPA5066 but on a little white tag said 5066AD - the new board I ordered was TNPA5066AC which ShopJimmy listed as a substitute part. Now the tv turns on again, but after about 5 seconds shuts off to 6 Blink SOS. Then I found the 2010 FHD Manual for the TC-P42S2, as I could not find one for the C2. I did one of the tests which said to disconnect SN20 and C10 and if the blinks changed to 8 that the SC was shot, being the C2 model the SC is built into the SN. Now I'm back to the SN being bad. I have tested the voltages that I could, VSUS 188.9V steady TPVAD -188.9, my 15V line on the VSUS connector measured 15.5V and all 15V lines measure 15.5V and the 5V lines measure 4.97V. I also tested if I disconnect SN2,SN20,SS11 and the result is 7 Blink SOS. I am now at kind of a stand still as I have looked everywhere for more info and can not find much in terms of service procedures. Does anybody have any Ideas or any test procedures I should perform? I don't think the panel is bad since it had at one time after being broken it worked like it should. Also another note, I did notice when it worked for its brief moment that it seemed to retain images after being reset, but when active it did not display the images.

[tw2005]

Re: TC-P42C2 - Need advice

This post p42x20 probably won't help you much, I found it confusing to read again and I wrote it!

Anyway, yes I had a lot of fun trying to understand the SOS blinks and trying to apply the 2009 model training to it and I suspect some of those isolation steps could be wrong for this one.

I got mine going in the end but the image is wrong, maldisharge, simply weird.

I had shorted Vsus(SOS4) on the SS board(common fault), corrupted EEPROM on the A-board(SOS1), Then I found corrosion on the flex cables from the A-board that damaged some octal buffer ICs on the A-board shorting 5V (SOS10), then somehow shorted out and IGBT on the SN ERC cct from the SS, still had issues, had both SOS6 & 8, followed that isolation procedure and it suggested SN board but I could not find anything shorted on it.
Took a punt and figured C boards could also cause SOS8, found a bad IC on the C2 board ( I think) replaced that and finally had a picture but not 100% correct.

No longer shutsdown but it's a basket case, however if you want to compare what blinks out depending what is disconnected, list them and I'm happy to try them out and post the results.

every board in mine is the same as yours except the A-board.

I know if I disconnect the interconnecting ribbon between C1 & C2 boards (C10)it goes SOS8.

SN20 + C10 = same SOS8

SN20 on it's own SOS6, poorly seated or corrosion on the ribbon can also cause SOS6, I had corrosion and used parts from a 42C2 to replace it.

SN2,SN20,SS11 I get SOS6 not 7

I can't see how you could get SOS7 with SN20 disconnected as the A-board needs that one connected to receive the SOS7 trigger from the SN board. By default , SN20 disconnected should produce SOS6, A-SN FPC DET

[fyca]

Re: TC-P42C2 - Need advice

This post p42x20
SN2,SN20,SS11 I get SOS6 not 7

I can't see how you could get SOS7 with SN20 disconnected as the A-board needs that one connected to receive the SOS7 trigger from the SN board. By default , SN20 disconnected should produce SOS6, A-SN FPC DET

So I retested this procedure and still get 7 blink SOS. Could it be a mis-diagnosis from my A-board? Also on my P-board I noticed that the 450V line filter cap is slightly bulged but not bulged enough to know for sure. Another thing I noticed is that when testing the VSUS I get 188.9V but after it shuts off the voltage drains off quickly, probably down to 6V in about 3 seconds, is that normal or maybe a sign of a bad cap? Then another thing that I noticed when testing voltage at TPVAD that maybe a tenth of a second before it shuts down the voltage dips then goes back to -188.9, it happens so quickly that I cannot see what it dips to, I might try building a RS232 cable for my meter and see if I cant record what my meter is seeing. I appreciate any and all input on this.

[fyca]

Re: TC-P42C2 - Need advice

After testing again I guess I was counting the blinks wrong. I do get 6 blinks with SN2,SN20,SS11 disconnected.

[fyca]

Re: TC-P42C2 - Need advice

So my bro came by and helped me test some points.

TPSN1 - 60V not stable, switched between + and -
TP97 - ~ -120V switches between + and - drops to -104 after screen on
TP98 - ~-163V after screen on drops to about -80V
TPVSCN - -43V
TPSS1 - 121V after screen on drops to 105V
TPVe - 123.7V
TPVAD - -188.9V right before the relay clicks off it dips to around -178V then back up to -188.9V then the relay clicks off.

[fyca]

Re: TC-P42C2 - Need advice

So my bro came by and helped me test some points.

TPSN1 - 60V not stable, switched between + and -
TP97 - ~ -120V switches between + and - drops to -104 after screen on
TP98 - ~-163V after screen on drops to about -80V
TPVSCN - -43V
TPSS1 - 121V after screen on drops to 105V
TPVe - 123.7V
TPVAD - -188.9V right before the relay clicks off it dips to around -178V then back up to -188.9V then the relay clicks off.

I think the TPVAD is what is triggering the SOS, but I don't know why. My VSUS lines hold at 188.9 stable.

[fyca]

Re: TC-P42C2 - Need advice

As I was reading your thread on the X20 I saw that you test the ERC Mid, I do not know the procedure for testing that, although I did try to measure it with black lead on white wire at SN3 and red lead on the brown wire, both wires test at ~120v for both brown wires.

EDIT: After testing again with black lead on chassis ground, this happens on both brown wires, the voltage starts at 15V then goes to 119V then 121.2V then down to 105V.

[fyca]

Re: TC-P42C2 - Need advice

Vdata - 54.6V steady

TPSOS6 - Starts at 4.2V then drops to 0V

[fyca]

Re: TC-P42C2 - Need advice

So now on to something new, I just removed my A-board and my SS to visually inspect both. Upon inspection nothing looks visually bad, but now I have a 10 Blink SOS. I took everything back apart and put it together again and I still have 10 Blink SOS. I don't know what happened. Also with SN2,SN20,SS11 disconnected and I test VSUS now it goes to 188.9V but dips 1/2 second before relay clicks off and I also get the 6 Blink SOS. Does this mean my P board is dead? Same thing with the 15V line dips before the relay clicks off.

[fyca]

Re: TC-P42C2 - Need advice

With only SS11 disconnected I get 6 blink SOS.

[tw2005]

Re: TC-P42C2 - Need advice

Sounds like the SS may have failed shorted, check vsus at SS11 to gnd on the board for short obviously isolated and check there's no residual voltage before you do.

Maybe also check P15V @ SS11 and SS23 P+5v for short to gnd.

SS11 disconnected should produce SOS6, mine does.

[tw2005]

Re: TC-P42C2 - Need advice

Mine when posted

Vs = 191.5V you 188.9V
Vad = -190V you -188.9V
Ve = 125V you 123.7V
Vda = 55V you 54.6V

Pretty comparable.

[fyca]

Re: TC-P42C2 - Need advice

Measured SS11 to ground - Shorted
SS3 to ground - Shorted

I'll take it back apart and see if anything is touching.

[tw2005]

Re: TC-P42C2 - Need advice

Measured SS11 to ground - Shorted
SS3 to ground - Shorted

I'll take it back apart and see if anything is touching.

Generally 4 shorted smd IGBTs RJP30E2.

[fyca]

Re: TC-P42C2 - Need advice

Would it be worth changing the IGBT's or just get a new SS? I could pick up a used SS on ebay for $30. In this case could it be more than 4 IGBT's, like I've read if something went wrong on a board it was probably caused by something else, personally would you change the IGBT's or just get a new board?

Edit: It looks like it would cost me about $20 for four IGBT's from Mouser. Used SS it is I guess. Hopefully it's not my P-board that shorted it. Would the IGBT's possibly also be my 6 SOS?

[fyca]

Re: TC-P42C2 - Need advice

Just as reference these look like they would be exactly the IGBT's I would need.
http://www.mouser.com/ds/2/200/irg7ia19upbf-89228.pdf

[tw2005]

Re: TC-P42C2 - Need advice

Just as reference these look like they would be exactly the IGBT's I would need.
http://www.mouser.com/ds/2/200/irg7ia19upbf-89228.pdf

They're not exactly the same as the originals are D-pak and RENESAS. This is a TNPA5072 SS? Specs are probably close. For $30 it's probably easier and safer to get a board. I rebuilt mine with subs but since I still have issues it's somthing I have a ? over whether it's part of the issue or not. other parts can fail like the FET driver IC.

I'd get the board, just takes that doubt out, for me adding postage doubles the cost so I chose component.

[fyca]

Re: TC-P42C2 - Need advice

Do you think the 15.5V on the VSUS 15V line might be a problem with my P-board or just within tolerance? I don't want to get a new SS just to have my P-board kill it again.

[tom66]

Re: TC-P42C2 - Need advice

That is fine for a 15V line.

[tw2005]

Re: TC-P42C2 - Need advice

unlikely you have a P-board issue,SS board failure is a common one for this model.