Panasonic Plasma TC-P42U1 my first plasma

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

The connections to su/sd boards are different. I would have to change them so I guess I will send it back and buy the correct board for over $100 used.
I don't want to tamper with board unless you are possitive it will work

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

In which case I wouldn't recommend it. The seller was incorrect, so he should replace it free of charge for you.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

seller contacted me already. he gave refund on good faithas long as i send board back.
i still need to find one though.
TNPA4829AD

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

Ok I finally got the correct sc board but I still have the 7 blink code so that wasn't the problem.

I could use more help figuring this one out.
Turn on
7 blink code and repeats
Black screen(nothing at all)
Replaced sc board/same problem
There is a green led on sc board that does not come on at all.

If I remove the flat ribbon cable on sc board that goes to main board,and leave power connected to sc board I get 6 blink code and green led on sc board comeson for a few sec. Then shuts off.

I could use any tips or help to figure out what board is bad.
I'm not smart enough to go through it component by component but I can check voltages and basics.
If you need specific pics just ask.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

Are buffers secured to SC properly?

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

Yes everything is secured and all ribbon cables look good.

I think it may be power board since I still get a slow voltage drop over time.
When I first turned it on and checked voltage to sc board I got 170v.
After a minute or two it was down to 40v.

I'm going to let it sit turned on for 5 min then recheck a few things tomorrow.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

I rechecked all connections
I unplugged power to sc and ss boards and turned tv on and rechecked voltages
To sc board pulsed 0-356v
To ss board pulsed 0-220v
Rechecked to sc board and it dropped to 40v
This mustbe a power board issue

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

If the SC is shorted, it will shut down the PSU...

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

Disconnected power con to sc and ss boards.
Disconnected ribbon con to sc
Turned on tv and watched power board voltage drop on connector(sc)
Steady drop about 1v every 2 sec for about 3 min.
Stayed about 1.5v

I don't get what might cause this outside the power supply board.
I eliminated sc/sd/su I think
Could main board or A board cause something like this.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

With SC/SS disconnected you will get 6,7,8 blinks (it usually won't even attempt to power up), unfortunately you can't isolated them easily on a Panny. But you are saying you get 220V briefly then it shuts down? On Vsus? That sounds too high...

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

That was a typo. Its hard to get an acurate reading when its dropping but its usually around 185vdc and drops 1v at a time slowly . It doesn't just shutdown or drop to 0v instantly

I just noticed when I plug it in I don't get a stby light. Then when I hit power I get codes.
Should it enter standby and front led light go on as soon as I plug it in?
The only sign of life is the relay click and codes flashing when I turn it on.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

If it was still powered on when it failed, it will default to powering on again, I think. Only if it's been put into standby somehow will it go into standby after plugging it in. 185V seems more reasonable, tad low for a Panasonic, as they are usually in the 200-210V range.

These TVs use a nice clicking switch for the power control but it's just like an ordinary power button for the main board. And when it's off the TV is in standby and using power, just not showing it.

[tw2005]

Re: Panasonic Plasma TC-P42U1 my first plasma

I'd retry shorting sc50 with no buffers connected. If SC is good the set will power on normally, if still bad i'm thinking SOS6 will come up.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

It powered up good and stayed on with constant 209vdc.

[tw2005]

Re: Panasonic Plasma TC-P42U1 my first plasma

Bad buffers I'd say because that to me means sc and ss are powered on. LEDs lit on both SS & SC boards I assume?

[tw2005]

Re: Panasonic Plasma TC-P42U1 my first plasma

Oh and if you still have the old sc swap it in and do again. You may now have a spare Sc for a rainy day.

[tw2005]

Re: Panasonic Plasma TC-P42U1 my first plasma

You could also try Su,Sd one at a time connected with sc50 shorted. I'd be interested to see what happens there as well. You may get half a picture??

The only thing I hope it does not do any damage to the SC, have not been in this situation before myself. Only fixed 2 SOS7 and both were Sc boards. have'nt struck dead Su/Sd yet. only worked on 4 other panasonics.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

There is a small ribbon that connects between the su and sd and the block diag shows a 5v line there so it may not work.

Before I buy sd/su boards is there any way to test them or the screen?
Service manual doesn't show much when you get to those boards.

I have a feeling it is a bad screen but who knows. It was from a pawn shop
I may end up with 2 spare sc boards

[tw2005]

Re: Panasonic Plasma TC-P42U1 my first plasma

I'm a little unsure but I think the way to go would be hook everything up. Disconnect SU41 only and power up. If SOS7, reconnect then disconnect SD42. This is with SC50 still shorted.

I'm assuming that's how your board connectors are labelled. See how we go. Not sure what SOS you see if bad panel.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

It powered on ok then I heard a pop on the left and a few sec later it shutdown with 6 blinks.
I did have time to look at the screen and saw it was lit and had a rainbow look