Panasonic TH-P50U30A 7 blinks

[tw2005]

Panasonic TH-P50U30A (Tc-P50S30) advertised as 7 blink bad P and SC boards.

Anyway one of these ones you wonder why you take on as it's one that has already been messed with.

First thing I notice, bridge rectifier missing. and a FET unbolted and removed to test

Rectified those issues and P board OK now.

Next i jump onto the SC expecting it to be dead- nope, it's good which I'd rather have bad SC and good buffers so this will be expensive.

SU is shot, quick check between Vfg and the outputs and there's shorts.

Did the same on the SD and all ok normal. I get consistant 0.73 which is what I would nomally see.

Totally removed the SU, jumpered SC50 still 7 blink, but ok with SD isolated.

Puzzled I did the resistance measurements, SU was no surprise but the SD was.

Results.

SD,

1 Vfo 5.8M
2.Vscn_f 7.2M
6. VF5V 29K

SU

8. Vfo 9.2ohms
6.Vscn_f 238k
2. VF5V 2.3ohms

Resistance checks look all wrong except maybe SU pin 6.

lets hope the panel is OK and I'm not about to blow a buffer set.

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

Just popped the back off the GT30 I'm working on, resistances on the SD are close to what mine has?

maybe although it says you can jumper Sc50 on the ST series and have the Sd pass , this ( U series) TV don't like it?

Was going to try out the upper from this GT but I can't get the fingers in safely so I have a buffer set coming, don't want to tear the panel ribbons on the GT

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

Just did 150km round trip, buffers I was getting both shorted

Lucky for the seller , I tested them otherwise would have been an Ebay loss for them!

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

Just removed the 1 IC on the Su which was shorted, threw the boards in and fired up, picture to the missing IC, but enough to get the serv tool up and this has done 5400hrs

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

picked up another 7 blink 50U30A over the weekend. Yep, same problem , shorted SU board.

Was hoping for a dud SC again, no joy. These TNPA5336 boards are hard to find or extremely expensive. I got lucky and found some from a ST30. Same board just has heatsinks and working perfect on this last TV.

This one only has 3800Hrs, quite incredible the little use really these have had.

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

now I know what's good I can confirm resistances using my fluke 73 with the red probe on the vfg plate.

SD,

1 Vfo 4.76M
2.Vscn_f 7.79M
6. VF5V 28.1K

SU

8. Vfo 5.52 Meg
6.Vscn_f 9 meg
2. VF5V 28.4k

[jjanssen7]

Re: Panasonic TH-P50U30A 7 blinks

thanks for recording this. Have worked on these and will do so again. These values are valuable!

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

thanks for recording this. Have worked on these and will do so again. These values are valuable!

no worries, I like to collect and annotate whatever I can for future use. I have been assuming the figures would have been closer to the 2010 models but they're not.

people will get differing results I guess depending on their meters but good to have some indicative examples.

[flocko]

Re: Panasonic TH-P50U30A 7 blinks

Hi TW hope the move went well, How are you doing on the buffer IC replacement . have got some more on order from China.I have replaced 8 on the trot ?I think I have the hang of them now, doing them by removing silicon then cutting the legs,low melt solder, clean pads off then take body of last with thin knife blade then clean up well, working for me Flocko

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

Hi TW hope the move went well, How are you doing on the buffer IC replacement . have got some more on order from China.I have replaced 8 on the trot ?I think I have the hang of them now, doing them by removing silicon then cutting the legs,low melt solder, clean pads off then take body of last with thin knife blade then clean up well, working for me Flocko

Went well, thanks. Buffer replacement, you must be a mind reader. I'm just reaching the point where curiosity is getting the better of me. Was thinking of starting a thread asking if anyone was getting into this.

After my last posts i think it was ricosavy and have removed 2 more chips cleanly which is a good start has made me wonder if i should go to the next step.

have ordered a cheap hot air station and considering these boards need just 1 chip I'm thinking of having a go.

My question is how is the chip being fitted compared to what panasonic does with that heatsinking grey sealant?

That's my deilemma, what product is used to seal the pins that's suitable for the voltage?.

Got any photos of your work?

[flocko]

Re: Panasonic TH-P50U30A 7 blinks

Will take photos when i do the next ones , I use Permatex 82194 ultra grey silicone i found someone on a US site that was using this, and the data form Permatex backed up my voltage and heat concerns . its sold as auto gasket, but has not been a problem in use. i do not use hot air just low melt solder run on the pins then wick off. when you fit do not drag solder as the pins will bend then you have to get them back on the pads, better to do corners then go pin by pin. IC are coming in at about £30.00 for ten from China

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

Will take photos when i do the next ones , I use Permatex 82194 ultra grey silicone i found someone on a US site that was using this, and the data form Permatex backed up my voltage and heat concerns . its sold as auto gasket, but has not been a problem in use. i do not use hot air just low melt solder run on the pins then wick off. when you fit do not drag solder as the pins will bend then you have to get them back on the pads, better to do corners then go pin by pin. IC are coming in at about £30.00 for ten from China

As always, value the input but what about the fact that this sealant is acetic acid based which from what I've read is corrosive to the pins?

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

maybe this?

[flocko]

Re: Panasonic TH-P50U30A 7 blinks

I dont know were you see that? would think if that were the case it would not be much good as a auto gasket sealer for metal parts ? that is what i use and until I have a problem will continue to use, Flocko

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

I dont know were you see that? would think if that were the case it would not be much good as a auto gasket sealer for metal parts ? that is what i use and until I have a problem will continue to use, Flocko

yeah, looks like i got mixed up then, looking again at the TDS, says it's oxime based.

Well that's worth a shot then I guess, easier to get.

[Nick's Tvs]

Re: Panasonic TH-P50U30A 7 blinks

TC-P50S30 7 blinks, with VS shorted to ground on SC.
Replaced all shorted components, and got the screen to prime, however the picture did not show aside from a few sparkles of red and maybe blue or green. I shut the set off fairly quickly after. I made sure all screws were tight, and all connectors were in properly. Tried one more time with the exact same result.

After further investigation, I realized that the previous owner had the brilliant idea to snap off the thermal fuse. So I went to shop jimmy to look at their picture and see what kind of rating it had and proceeded to replace the fuse.
After doing so, the tv went back into 7 blinks however the SC board is no longer shorted out, and all components replaced are holding.
I removed the fuse again to see if the panel would prime again, and it has not. It is stuck in the 7 blinks. Now I also went ahead and checked readings between vfg and sd/su
SD
1 Vfo O.L
2.Vscn_f 25M
6. VF5V 25M

So obviously I am doing something wrong here but not sure what.

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

I think isolate the sd/su including the 4 Vfg bolts and jumper sc50, powerup and see where yo're at if you have not done so .

What thermal fuse are you referring to?

Any pictures

[Nick's Tvs]

Re: Panasonic TH-P50U30A 7 blinks

Jumped at SC50 and I got the tv to stay on with about 219 volts on the VS line and about 124 at the VFG plates. So the repair on the SC is holding, and the tv is turning on without the SC and SS, however I still don't have that thermal fuse on the board which is confusing as to how its working with out it.
So that thermal resistor I am talking about is the white one labeled
5w 2.2ΩK 133 on the picture attached. It is located between the 2 connectors to the lower buffer and the 2 center vfg plates

http://assets.shopjimmy.com/media/ca...c1mnux-top.jpg

I had placed one in between where the original leads were cut off but it was removed for the SC50 test. Please see picture attached for what I actually have in my set up.

[tw2005]

Re: Panasonic TH-P50U30A 7 blinks

R515, 2.2ohm 5W ceramic needs to be there. have you looked at the schematics?

there was nothing in the photo except a vacancy, I had to look at SJ to figure it out.

[Nick's Tvs]

Re: Panasonic TH-P50U30A 7 blinks

Yes that is what I was pointing out, the previous owner of the tv tried to fix the set by cutting out the ceramic resistor. I had no idea that he had opened up the tv himself and did that until I tested the tv after fixing the short on the sc board.
What voltages should I be expecting on the VFG plate? I will go ahead and place the resistor back on there from another board and test again for voltages.