Panasonic Viera TC-P50G10 7 Blinking Red

[landyboy]

Picked up another freebie, (it amazing what people throw away). I know this is a common problem and will do some thread searching. I haven't worked on a Plasma yet but I couldn't pass this one up. Upon my initial inspection I definitely found a problem as you can see in the close up picture there is an area of arc'ing maybe lightning damage on one of the boards.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Here's a closer picture of the burnt area, pretty much thinking I need a SC board.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Do you think changing the 2 resistors and the diode that are fried would be worth a try or do you think the board is beyond repair?

[Clydeuk]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Actually looks like something may have been spilled in there that caused that, from the photo's. Up to you how you tackle this, I have the full circuit diagrams, you can try to repair the SC board, and there is also a way to run the set with the buffers disconnected to prevent any damage to them by jumpering a connection. So assuming the buffers have survived I would suggest you start taking some readings around that dodgy looking area.
Also test the connector that carries the VS and 15v supplies to the SC board, see that it's not shorted to ground on one of those rails.

[Clydeuk]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Wish I was in your area, I've never found much chucked out apart from some CRT's. These are excellent sets, definitely the best Plasmas and well worth fixing providing the display hasn't failed.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Thanks for the help. I am new to this (plasmas especially) can you point me in the direction of the VS and 15v supply.

[Clydeuk]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Well actually there only appears to be a VS supply on the SC board there, I think the 15v comes via a different path. Anyway on your first picture at the top left is a large connector with a blue and white wire. Check resistance on the SC board from the white connection to a ground point (or between the two points on the connector). Short there means more investigation and there's likely FET damage along with the problem you have observed. Panasonic call it VSUS rather than VS.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Ok from the white connection to ground is greater than 1 meg ohm. Resistance varies across the connector but is not short.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

I do have a short from the white side to one side of the burnt diode.

[tw2005]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

15V & 5v is via SC20

[Clydeuk]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

The white wire carries the VSUS voltage, can you tell me the location of the diode?

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

D618

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Ok I am having problems finding the 5v and 15v.

When I power the tv on with everything connected it give me an initial voltage of around 190 volts feeding each board SC... but after a few seconds the voltage drops...

[tw2005]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

It drops beacause of the SOS shutdown, TP16,17 - gnd or across c563(c16563) 100uf 10v cap is the 5V in,TP6,7,82 - gnd 15V in, also on Pin 8 IC581, pin 11 IC521, pin4,5 IC791,

you could measure the resistance there to ground in case something has shorted on the 5V & 15V

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

no 5v or 15v present. 500ohm short between IC581 pin 8 and ground. Also D618 has solid short across it.

[tw2005]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

I have a SC which had 380ohms, one of the 2 tiny 20pin buffer chips had shorted. Still have not got that one going either. TNPA5081, similar cct but where you have C563 I have 10uf ceramic with a 5.6K resistor across it. I get 5.6K on P5V which suggests across vcc-gnd must be much higher in value ince they're in parallel.

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

Would this be a suitable replacement for the damaged diode?
http://www.digikey.com/product-detai...9AT-ND/2143013

[tw2005]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

RF101L4STE25

http://www.digikey.com/product-detai...5CT-ND/2331722

[landyboy]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

One last quick question. I need the small resistor marked 473 (I have a few of the 683) I can find the 473 on Digi but I'm not sure what wattage?

[tw2005]

Re: Panasonic Viera TC-P50G10 7 Blinking Red

If you have not already, download the manual. Order extras and there's probably more than just those 2 items. I'd expect that FET Q604 blown as well and those smd resistors can be bad even though they may look ok.

ERJ8GEYJ473

Specifications
Case Style Moulded
Depth 1.6mm
Dimensions 3.2 x 1.6 x 0.6mm
Height 0.6mm
Length 3.2mm
Maximum Operating Temperature +155°C
Maximum Temperature Coefficient +200ppm/°C
Minimum Operating Temperature -55°C
Minimum Temperature Coefficient -200ppm/°C
Package/Case 1206
Power Rating 1/4W
Resistance 47kΩ
Technology Thick Film
Temperature Coefficient ±200ppm/°C
Tolerance ±5%

http://www.digikey.com/product-detai...KECT-ND/203339