Panasonic TH-42PZ800B 12 blink fault

[Paniman]

Hi everyone

After a successful fix on a rare 6 blink fault I had with a working TV for two days it has now developed a 12 blink fault (SOS sound) A board fault

I have taken the rear cover off again and check the power supply 15 volt out from power supply P6 pin 1 and it rises to only 1.5 volts before shut down to 12 blink code. This was with the A12 connector to the HB audio amp board connected and then disconnected with the test performed again.

Does anyone know if the 15 volt transformer on the power supply on this TV have a thermal fuse buried under it?

Many thanks

Regards

Paniman

[sordids999]

Re: Panasonic TH-42PZ800B 12 blink fault

I'm sure Tom will try and help when he's free

[tom66]

Re: Panasonic TH-42PZ800B 12 blink fault

15V fault would not trigger this.
This is an audio fault - bad shorted speaker, pinched wiring, bad A board +9V or bad A board audio amplifier ckt.

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

Ok all

I did disconnect the speakers out from the audio board
And have checked all wiring looms for pinching none found is there anyway I can check if it is the audio amp or A board without parts?

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

Sorry I meant to say I still have 12 blink with speakers disconnected

Tom could you please explain the lack of 15 volt between turning on and 12 blink as I was under the impression from the block diagram that the sound amp was driven by 15volts from P5 to PA5 then PA5 to PA6 though the pa board PA6 to A6 through A board and then out on A13 and in HC board on HC 13 and on to the audio out board

Just trying to get my head around the lack of 15volts (1.5 volts max is all I am seeing)

Many thanks

Paniman

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

One more thing the ss and sc board green led are not lite before the 12 blink fault is shown is this normal with this fault?

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

Hi all,

I guess tom is fairly busy at the moment(thanks tom for you inputs so far) is anyone else able to answer my questions?

Many thanks

Regards

Paniman

[tom66]

Re: Panasonic TH-42PZ800B 12 blink fault

It can be normal.

To test panel (SC,SU,SD,SS,D,C# boards) and PSU (P & PB board), disconnect all connectors from "A" board. When you plug the TV in, the screen should glow dim first, then glow full white. The fans will not spin and the power light will not glow. Don't run it in this condition for more than 5 minutes.

This would tell you the fault is A board related.

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

Hi tom

Many thanks for the info I will try this and come back with the results

Regards

Paniman

[Paniman]

Re: Panasonic TH-42PZ800B 12 blink fault

Hi tom

I did what you said spot on had the white screen. it's the A board. Anyway I can repair the A board or narrow it down to a specific location on the board? These board seem to be hard to come by

Many thanks Tom

Regards

Paniman