Panasonic TX-P37X20B

[snipersquad100]

Re: Panasonic TX-P37X20B

TNPA5072 SS board
if you mean the board on the left under the a board then yes its TNPA5072.
I TOOK SOME VOLTAGES on the power supply, arss backwards I know, P6 had the following; Pin 1=0v 2=0v 3=0v 4-6 gnd 7=0.3v 8= 0.3v 9=0.3v 10-11 gnd
P7 had the following Pin1= 4.99v 2 gnd 3=0v 4=0 5=0v 6=0v 7=0v 8=0v 9=0v 10n/c 11=0v 12=4.9 13n/c 14=4.9.
I assume the tv is not switching on or there no power anywhere.

[tw2005]

Re: Panasonic TX-P37X20B

remove SS11 and check Vsus to gnd for short cct, use the 42" manual if unsure of the pins, same SS essentially.

The 4 RJP30xx short on those boards.

[tw2005]

Re: Panasonic TX-P37X20B

usually we refer from the side the boards viewed so from rear SC on left, SS right but yes you've got it under the A

[snipersquad100]

Re: Panasonic TX-P37X20B

removed ss11 coming from p11 on the power supply. I probed pin 1 on ss11 to gnd and its 0.15ohms I take it that's a short.

[tw2005]

Re: Panasonic TX-P37X20B

Correct, now all you have to do is pray the SC survived. All I can suggest there is disconnect SC2 and check Vsus to gnd and at SC3 Check Pin 1 gnd to either 3 or 5 for short.

It's probably ok but? If you wanted to go a bit further, check P5V at pin 1 at SC20 to gnd (resistance) and P15V pin 29/30 (resistance)

[snipersquad100]

Re: Panasonic TX-P37X20B

I not sure if im to disconnect sc3 b4 taking measurements so I did both Pin 1 to 3 and 1 to 5 where 0.12 ohms with sc3 plugged in but 42k ohms each when sc3 was disconnected.
pin 5 to gnd on sc20 is 4.7k pin 1 159.3ohms, pin 30 5.6k, pin29 4.7k.

[snipersquad100]

Re: Panasonic TX-P37X20B

sc2 to ground is in the Mohm and dropping.

[tw2005]

Re: Panasonic TX-P37X20B

Yeah I'll try to be more precise but you want nothing else interacting with the board so cables need to be removed including SC 20. So SC3 short removed when cable disconnected would be due to the SS being shorted, you'll notice that lead goes back to the SS, 42k sounds ok.


Sorry mate, i've got the pins arse about. Must have been looking at the A board side.

isolate any cables and ribbons from the SC otherwise the other boards affect the reading.

Pin 30 is P5V so 5.6K is spot on based on my SN,

Pin 1 is P15V, recheck that after the ribbon is removed, sounds low but I might dig out the meter and compare my SN.

Pin 29, delete

Pin 5, delete, never mentioned

Would still like to know resistance on SC2 vsus to gnd

[tw2005]

Re: Panasonic TX-P37X20B

sc2 to ground is in the Mohm and dropping.

Sounds ok although with mine I get a few hundred K ohms and then when I probe again get Mohms but it's not shorted.

[snipersquad100]

Re: Panasonic TX-P37X20B

pin 1 is 1.2k
vsus to gnd on sc2 is 120M ohms

[snipersquad100]

Re: Panasonic TX-P37X20B

v sus to gnd just keep dropping. take to long to settle. I got it down to 20meg after two mins. I don't think it shorted.

[tw2005]

Re: Panasonic TX-P37X20B

1.2k is probably ok although on mine I get 1.4k ribbon removed, 1.2k with it connected. On pins 3 & 11 on 16pin IC521 that's where the 15V feeds the FET driver IC.

Could confirm those points are the same to gnd.

120Meg on SC2, that's different. Must be a very good meter you have, I think mine is limited to 30Meg.

I get about 300k first probe then release and reprobe 2.5M for SC2

Sc3 depending on which way I have the probes polarity wise 80K one way, 60K the other but for all we know your cct could be different.

On SC3 cct, Q441 and Q451 work together, are they DG501 transistors? i managed to have one short there during my fault finding, could just quickly check each for short probably wasting your time a bit now.

there's nothing wildly crazy or shorted so fingers crossed should be ok.

[tw2005]

Re: Panasonic TX-P37X20B

v sus to gnd just keep dropping. take to long to settle. I got it down to 20meg after two mins. I don't think it shorted.

If you have not tried this yet but short those 2 pins at Sc2 to take the charge out and try one polarity. probe once note reading, lift a probe, the reprobe and note reading.

Short pins again, reverse the leads and do the same again probing twice and note the results.

[snipersquad100]

Re: Panasonic TX-P37X20B

yes pin 3 and 11 are 158 ohms each.
my dmm is nothing exciting lol I got a uni-t ut61e and an amprobe am-220
Cant find a datasheet on the dg501lw or the dg501rp but I take it they some kind of fet in which case test ok.

[snipersquad100]

Re: Panasonic TX-P37X20B

sc2 im getting 4.5 meg one way but nothing the other way round.

[tw2005]

Re: Panasonic TX-P37X20B

yes pin 3 and 11 are 158 ohms each.
my dmm is nothing exciting lol I got a uni-t ut61e and an amprobe am-220
Cant find a datasheet on the dg501lw or the dg501rp but I take it they some kind of fet in which case test ok.

Well now I'm confused a little. First you say 159.3ohms, then 1.2K and now back to 158 ohms?

[tw2005]

Re: Panasonic TX-P37X20B

sc2 im getting 4.5 meg one way but nothing the other way round.

Sounds more like it, maybe the way your meter works as the cct is active and being charged when the probes are hooked up, but not low enough to be an issue like a short which is all we're concerned with.

[snipersquad100]

Re: Panasonic TX-P37X20B

sorry pin 11 on ic512 ic 1.21k and pin 3 is 1.21k where I got that other figger from I don't know. must of had my meter on wrong setting. lol

[tw2005]

Re: Panasonic TX-P37X20B

Ok , you had me worried. last time i saw something around the 100 ohm mark there was on a shorted out TNPA5081 SC board I was fixing and that FET driver IC which is the same part as that one was definitely bad.

Might seem extreme wasting so much time on it but the info may help someone else and chances are it'll be fine.

I just hope you have a better outcome and restore to 100% unlike mine which runs now but has bad image like maldischarge which I can't work out.

Any plans for the old A board?

[snipersquad100]

Re: Panasonic TX-P37X20B

I just ordered that TNPA5072AD hopefully it will fix it.
no plans for the dodgy a board.
Thanks for the help.