Panasonic TC-P50G10 10 blink code

[Clydeuk]

Re: Panasonic TC-P50G10 10 blink code

It's been a while since I've tackled one of these, as you will expect it's not easy from a distance. I believe I have the service manual for this. Where I worked they all board swapped and wouldn't let me get down and dirty (though I sometimes did on the quiet!). Since I finished I have worked on a few pannys to component level, so I'll have a look over the circuit and see if I can come up with anything, though it sounds like you may be on the right track. I'm not sure off the top of my head what the sub 9v is used for. Is it a dead short that you are measuring, or low ohms?

I vaguely recall mention of checking for a foreign object in SD slot, and trapped speaker wires, whether this has anything to do with the sub9v or not I don't remember.

[tom66]

Re: Panasonic TC-P50G10 10 blink code

Foreign object causes 3.3V short, I think? Not sure. I have the service manual on my website.

[tom66]

Re: Panasonic TC-P50G10 10 blink code

BTW, You can see a video of where I used this technique to locate a short on the T-con board of a Samsung LCD (skip to 3:10 if you want to see the technique only.)

https://www.youtube.com/watch?v=7Xz-iSaEAb8

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Thanks Clydeuk bring it on! It's pretty much a dead short to ground at all 9V test points Ive found.

I have just went thru the 22 pages of A Board on the service manual and wrote down wherever I saw the SUB9V lines, there is about 8 along with the page in manual if you guys have any thoughts to what is likely to fail, Im going to start to try to isolate each if possible..

IC5480 - Page 48 - Analog ASIC
IC5401 - Page 49 - 9V regulator IC and detect circuit
JK3000 - Page 51 - AV terminals - bunch of diodes
JK3701 - Page 52 - Side AV terminal - 3 diodes
IC3001 - Page 52 - Audio Video SW IC
IC1100 - Page 53 - System MPU - Detection
-------- Page 56 - HDMI ports
-------- Page 61 - SUB9V just going into 3-7 capacitors

[Clydeuk]

Re: Panasonic TC-P50G10 10 blink code

You're right about the 3v3 foreign object, I remember vaguely reading it but never encountered it. I think isolating is probably the best way, though where to start is the thing, the components are tiny on these. I'd be suspicious of SM capacitors I've had quite a few fail lately. Have you got low ohms tester? I've used my ESR meter a few times to locate a short, the closer you get to the offender the lower the resistance gets (talking fractions of an ohm!)

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Hmm I can try using my esr meter although its got big bulky alligator clips. I remember seeing a product that was supposed to find a short, the closer you got the higher the readings but I don't know whatever happened with it.. Id hate to start removing any more tiny SMD components and cutting traces...

What's the functions of the Analog ASIC and AVSW IC?

A lot of the diodes in the offending area are passing voltage both ways in circuit, I guess because of this short.

This board is $150+ if you can find it. The TV is not even that old it's crazy.

[Clydeuk]

Re: Panasonic TC-P50G10 10 blink code

I think the AVSW will be input switching, not sure about the ASIC it means "application specific integrated circuit" I believe, whatever function it's serving, I seem to have lost it on the diagram. I'll see if I can find out more tomorrow with a fresh head. I usually find IC's in low power circuits tend to be innocent although it doesn't stop me eyeing them with suspicion.

I know we never repaired an A board where I worked, perhaps because we covered warranty repairs so this is very interesting.

[Clydeuk]

Re: Panasonic TC-P50G10 10 blink code

Just before I go to bed, this all appears to be in the analogue signal input sections, I think the ASIC is going to be a custom IC, so hopefully that's innocent. You could always try and get hold of a faulty board off ebay and hope that it's got a different issue so you can use it for salvage, I've done that a few times with motherboards, T-Con etc.

[tw2005]

Re: Panasonic TC-P50G10 10 blink code

C1ZBZ0003972 $7-12 ea having a quick google from Sears, etc

Hope you do fix it at component level. Good luck.

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Ok Ive still not given up one this one... I've isolated a couple 9V points so far without finding the short, so I came to this IC and decided to cut the trace at pin 13.

I still have a short to ground on both sides of the cut trace, the chip side is just slightly lower ohms than the other side.

Does this mean that IC is shorted and something else is too, or am I missing something else?

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Ok found the problem(s). Removed L3000 and short went away. IC3001 and IC5480 both are shorted.

Not sure about replacement of these! I think I will check to make sure 9V is back now that those are out of the circuit and if TV comes on..

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

The 9V did not come up, maybe the 9V regulator IC5401 is bad too, I had ordered that in the beginning will try replacing tomorrow..

That would be all 3 major components on the 9V line.

The 2 IC's seem to be for analog inputs, so Im hoping that it will at least come on and work with HDMI for now..

[tom66]

Re: Panasonic TC-P50G10 10 blink code

I am thinking if they fried then a power surge probably shorted them internally.

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Damn I replaced the regulator and same thing. Im getting the 14+V in but only about 1.5V output. There is no more short on the output side so I don't know why the 9V is not there.

[tom66]

Re: Panasonic TC-P50G10 10 blink code

Don't have to be just a short, could be excessive load (possibly just 0.1A for that type)

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

Is there a way for me determine that? I have the 9V removed from the 2 bad IC's, I think the only place it's still going is the system MPU.

I also rechecked the other voltages at D5521 and D5522 in pic, I have the F15V (14.4v actual), the 30V, and the 5V, just not the 9V.

[tom66]

Re: Panasonic TC-P50G10 10 blink code

You need a power supply capable of a little more than the 9V battery you have. 6xAA may do, with a resistor of around 18 ohms, to limit the current to around 500mA.

Ideally, you would use a constant-current constant-voltage bench supply, as it would work a lot better.

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

That's fine, but at this point I don't what else am I looking for that could be not letting the 9V come up?

I'm guessing here but take a look at the IC5480 schematic. I cut trace at pin 13, but you can see there is also a connection to pin 9 thru R5530, do you think that's a possibilty?

[tom66]

Re: Panasonic TC-P50G10 10 blink code

R5530 is too high resistance.

[kevinm34232]

Re: Panasonic TC-P50G10 10 blink code

OK. Say I get the 9V power supply, how would I go about testing for excessive load?