Panasonic TH-P46G10A

[UND312DOG]

Hi all,

I was in the middle of watching the footy and my viera died. The screen rainbowed then cut out. On the front the green button became red and flashed 7 times over and over. Now will the help of this forum I have come across the test procedures. I will post my results. But I think it's not looking good.

1. Proceeded with the isolation test of the SU and SD board with a jumper on SC50. Resulted with the tv staying on but a black screen. Check.

2. I then powered down. Took the jumper off SC50. Fired it up. 7 blinks again. According to the repair manual that means a faulty SD/SU board.

3. Moved on to doing a resistance test of the SD/SU/SC boards. This is where it gets nasty. I'm unsure of where to go next. But here are my results for the gurus.

SU Resistance Test -
SU41 Pin 2 - GND (200m ohm scale) = 0.14

SD Resistance Test -
SD42 Pin 9 - GND (200m ohm scale) = 0.09
SD42 Pin 1 - GND " " = 0

SC Resistance Test - (20k Scale)
Pin 3 - 2.94k Ohms
Pin 5 - 5.5k Ohms
Pin 7 - 0

Where do I go from here. To me it's seems like all three boards are RS. Maybe it's the panel that's fried them. Thanks in advance.

Shane.

[tw2005]

Re: Panasonic TH-P46G10A

If the Sc passed with the SC50 buffer bypass then it's good. Pin 7 does not apply to your model at SC42, pin 3 & 5 do and match the values in the guide. SO SC should be ok.

[UND312DOG]

Re: Panasonic TH-P46G10A

Ok. So SC is good. How do I go with further testing SD and SU? What is your take in the readings of the resistance levels.

[tw2005]

Re: Panasonic TH-P46G10A

How good's the meter? 200 Mohms is pretty high, what other ranges do you have?

[UND312DOG]

Re: Panasonic TH-P46G10A

It's only a cheapie. Only use it for home use. 2m is the next down.

[UND312DOG]

Re: Panasonic TH-P46G10A

http://m.supercheapauto.com.au/Produ...omotive/156452

Nothing special.

[tw2005]

Re: Panasonic TH-P46G10A

Try these again on the 2Meg range, Also does it have continuity buzzer at all?

SU Resistance Test -
SU41 Pin 2 - GND

SD Resistance Test -
SD42 Pin 9 - GND

SD42 Pin 1 does not apply for yours.

[UND312DOG]

Re: Panasonic TH-P46G10A

Yep. It has continuity. That what I bought it for. Automotive use.

I'm at work ATM. Will give it a test and get back to you. Thanks again

[tw2005]

Re: Panasonic TH-P46G10A

Yep. It has continuity. That what I bought it for. Automotive use.

I'm at work ATM. Will give it a test and get back to you. Thanks again

I've had trouble in the past with readings given by cheap meters although this one may be ok, I'm use to a Fluke Auto ranging meter .

You could also set to continuiy at those test points and see if it constantly beeps and also if you probe the gnd plate and then slowly slide the other probe along the ribbon connectors and listen out for dead shorts there.

All depends how fast this meter reacts as to how fast you move the probe.

[UND312DOG]

Re: Panasonic TH-P46G10A

Going off what you are saying. I checked continuity from ground to the connectors and I'm pretty sure it was showing continuity.

[UND312DOG]

Re: Panasonic TH-P46G10A

Though I did that this morning. I will double check that also tomorrow. If it is the case. What would be the next step.

[tw2005]

Re: Panasonic TH-P46G10A

if you have dead shorts then the buffer is bad, replace the boards.

TNPA4786, TNPA4787

could be a couple of versions, I expect yours has heatsinks?

assuming we're talking constant beep and a reading of 0 .

[tom66]

Re: Panasonic TH-P46G10A

Most bad buffers I've found resistance of about 10 to 50 ohms to the outputs, definitely bad.

[UND312DOG]

Re: Panasonic TH-P46G10A

Yep. Heat sinks on the ic's

[UND312DOG]

Re: Panasonic TH-P46G10A

Ok tested this morning. Results as follows -

SU Resistance Test - @2m ohms
SU41 Pin 2 - GND = 0
Continuity - Solid Beep - Reading 008

SD Resistance Test - @2m ohms
SD42 Pin 9 - GND = 1.018
Continuity - No beep - Reading 1

[tw2005]

Re: Panasonic TH-P46G10A

SU is dead, SD is the tricky one because they quote just over 2 meg ohms. Whilst it may not be completely shorted, could be suspect.

Try again on the Sd but reverse the probes in resistance. Also when it was in diode did the reading increase and then go 1 which is out of limits?

Then try resistance in the next range up from 2M and try both polarities with the probes.

[UND312DOG]

Re: Panasonic TH-P46G10A

Measured the SD again @200m ohms. 0.13 and reverse 0.12.

In regards to the continuity, it just stays at 1 when I touch. I also switched the probes around from that and it shows 0998.

[tw2005]

Re: Panasonic TH-P46G10A

Too hard to give you a 100% answer whether good or bad. Do you get any shorted outputs between gnd tab and any of the ribbon connectors?



The SC board often goes in these and are virtually impossible to source and expensive, so last thing you want to do is have a bad buffer blow it.

How much of a hurry are you to fix this?

The SD is being tested on it's own, not connected to the Sc or SU?

[UND312DOG]

Re: Panasonic TH-P46G10A

Both cards are now out. And showing the same results. I'm not sure where to test for the shorts your speaking of.

I've had a look online and can get both cards for $25usd. Shipping is the killer. $80 usd for both parts delivered.

http://www.tristatemodule.com/showpr...6s1-tx-p46g15b

http://www.tristatemodule.com/showpr...6s1-tx-p46g15b

[UND312DOG]

Re: Panasonic TH-P46G10A

Ok. Tested the SU between GND and the four ribbon connectors. Getting a beep on the second ribbon connector on about four pins.

Tested the SD on all four ribbon connectors. No beep.