Panasonic P50U50 was blinking, but now won't?

[tucocaps]

This one really has me stumped...

The panel is completely broken, and power LED had been doing the 7 blinks every time I tested it.

Finally got around to taking the back off today, to see what parts I could salvage. I was confused on which board was the SU, and temporarily disconnected power to the SS board, and then the SS board data ribbon instead.

So, I reconnected everything as it was, twice, and now it seems no matter what, the relay will just click once. I can see the mainboard optical out light up briefly, and then shutdown. No blinks at all Disconnected SU, and same results.

Could I have possibly burned the power supply by just unplugging, and then plugging back in?

On a side note, I was a bit "shocked" to see the small power plugs going to the SS and SD boards still hold some kind of charge even after unplugging. There was an arc 2-3 times trying to plug those back in (too quickly I guess?). I thought these modern power supplies had some sort of drain mechanism on the capacitors, but I guess not? Hope it's not enough juice to give me a heart attack

Thanks for any ideas on this one. I'm going to try leaving it unplugged for awhile, but I'm not sure that will help.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Any ideas on this one?

Should the set power on if I unplug everything from the PSU except the mainboard? Just trying to narrow down the problem...

[tw2005]

Re: Panasonic P50U50 was blinking, but now won't?

7 blinks I would expect with cracked panel.

You may have spiked the A board or SS?

So what are we talking here, locked solid stdby led or no stdby led at all?

I don't have a manual for this so hard to know what's what but some of these have the key panel routed via the c board.

i guess at this stage you want to see an attempted startup with error blinks?

try disconnecting sc20,sc2, ss11, p35 and see if anything changes.

If I was testing this, I would have disconnected the sd/u and jumpered sc50 but cracked / possibly shorted panel, risk of damaging c and SS boards.

Not something I've been faced with. maybe meter out the Sc2 and SS11 connectors and see if there's low ohms, test all the IGBTs for short cct.

Normally i'd suggest disconnect sc2, ss11, 3 white ribbons at the A board, p35 and try to turn on but if that keypad is routed via the c, nothing will happen.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Thanks again TW!

I think I was again confused while working on this set. It is indeed throwing the blink codes, but I forgot that I have to push the power button after plugging in to make it do that.

So, I have 7 blinks. If I disco the couple of small vertical white plugs going to the SC board, I still get the 7 blinks.

With Panasonic and a cracked panel, and assuming the panel is the root cause of the 7 blink code ... could I simply disco all the panel connection ribbons from the left and right side? I'm trying to see if there is any way to isolate the panel and find out what "good" boards I might have.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Doing more tests, the only thing I've found that I think may be helpful...

Disconnecting SU/SD , or one , or both, yields the same 7 blinks.

Disconnecting SC causes a distinctive short higher pitched buzz upon pushing the power button , that I do not hear when it is connected. I *think* the sort of buzz you'd hear when the unit is powering on. It then quickly powers off and throws 8 blinks (instead of 7).

I've tried many other combos of disconnecting SS, etc. but none seem to show any unique results.

Is this a main board issue, or would I need a working SC in order to say for sure?
Also, I'm still wondering about completely disconnecting the broken panel. Can having it connected cause any troubles with the SOS codes?

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

... and yes I do realize I said in a previous response that I get 7 (instead of 8 blinks) when SC is disconnected. Not sure on that, or if it is doing both at random? I know the buzz is there when SC is disconnected, but with everything else connected.

[tw2005]

Re: Panasonic P50U50 was blinking, but now won't?

some light reading for you. sc20 disconnected throws 8 blinks, bad sc or buffers / panel 7 blink, disonnected buffers 7 blink whichis why I suggested sc50 jumpered with the buffers removed, disconnected panel from ss 8 blinks.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Thanks again. Getting there I hope

I just found the SC50 jumper and jammed a mainboard jumper in there. Still 7, but I didn't disco the SU/SD. Going to try that next. I'm assuming you mean do that, and if 8 blinks, then also disco panel from SS and power again.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Woo hoo! Got a power on with SC50 jumped, SU/SD disco'd, and everything else connected.

I can actually see the power led's now on SC and SS. Only problem I've not seen before... set has a really loud buzzing noise coming from it. Sounds like the one I described earlier, but now constant. Is that just noise from the cracked panel? Having trouble locating the source.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

Definitely sounding like panel noise. Louder at front, and sort of oscillates in tone.

With the SC50 jumped, and power staying on, would this mean SC and all other boards except SU/SD are likely OK?

[tw2005]

Re: Panasonic P50U50 was blinking, but now won't?

Definitely sounding like panel noise. Louder at front, and sort of oscillates in tone.

With the SC50 jumped, and power staying on, would this mean SC and all other boards except SU/SD are likely OK?

yes, panel is shorted, you'll have to get a multimeter to check the buffers. if the tv was on when the panel shorted, i'd expect shorted buffers. i've purchased 2 complete boardsets from 2010 series with cracked panels, both had shorted sd boards.

if the tv stayed on then it's detected no errors.

that is the best i can do for you.

[tw2005]

Re: Panasonic P50U50 was blinking, but now won't?

Mate, it has a shorted panel, it passed startup, turn it off and move on before something else fails.

[tucocaps]

Re: Panasonic P50U50 was blinking, but now won't?

thanks again TW! I tested one of the HDMI inputs for sound, and it worked. Unplugged after that , and will be stripping it soon. I'm assuming I'm good to go on all but the two buffer boards, and I don't like keeping those around from cracked panels anyway Too much bad luck with them...