Panasonic P42X20E 4 red blinks

[V3dran]

Hello, 2 week ago my panasonic P42X20E stopped working giving 4 red blinks.

The board that certainly must be replaced is the SS (the tv service near me tried to fix it but is not possible), but maybe also the SN.

When I turn on the TV I get as I said 4 red blinks, the led on the SN is not on.

Is there a way to test if I must also change the SN board before the SS replacement?

Here are some pics of the boards.

Thanks for the help

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Ok, I got the tv back and tried to isolate the SS board (removing the conncector SS23), still 4 blinks
If I isolate the SN board I get 6 blinks (7 removing also SN20).

Am I correct or the TV must work if the SS board is isolated and everything else is theorically ok? It's a 13 gen panel

In my case the SN board should be fried for sure (no green led on it)?

Thanks

[tom66]

Re: Panasonic P42X20E 4 red blinks

Do you have a DMM?

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Hi tom, yes I do, can you please tell me what I have to check?

[tom66]

Re: Panasonic P42X20E 4 red blinks

Check the voltage on the brown and white wires going to the SC/SN board.

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Ok, I'll check it tomorrow since is late and also I have to replace the battery of the MM since is gone.
I'll post the results tomorrow

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Ok, I setted the DMM on DCV 200, removed the connector SN2 and probed, it shows 200 when I turn on the TV, then goes down.
The same with the SS11 connector on the SS board

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Before the TV "clicks" :
P11 pin1 200V then goes down
P11 pin4 14.9V then 0
P2 pin1 200V then goes down

I also noted some black parts on the connectors P11 SS11 and P2, SN2 is ok

If the boards are connected I get 0 on any pin if I'm not wrong

[tom66]

Re: Panasonic P42X20E 4 red blinks

So you are saying the 200V ("Vs") drops when the SN is plugged in? In which case, the fault is on the SN.

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Everything is connected as should be:
P11 pin1 0
P11 pin4 15V
P2 pin1 0

P2 (Vsub to SN) disconnected:
P11 pin1 0
P11 pin4 15V
P2 pin1 0

P11 (Vsub to SS) disconnected:
P11 pin1 0
P11 pin4 15V
P2 pin1 0.5V

Both P2 and P11 disconnected:
P11 pin1 200V
P11 pin4 15V
P2 pin1 200V

[tom66]

Re: Panasonic P42X20E 4 red blinks

This points to either both boards being bad or one board interacting with the other. Can you disconnect the brown flex connector on the right hand board (SS) and repeat the test with and without power going to it. It could be a bad panel.

[V3dran]

Re: Panasonic P42X20E 4 red blinks

I removed the connector SS23 on SS witch goes on the C2 board:
P11 pin1 0
P11 pin4 15V
P2 pin1 0

Then I tried to remove all the connections on the SS (SS11, SS23 and SS3):
P11 pin1 0
P11 pin4 15V
P2 pin1 0.5V

Don't tell me that it is the panel
I hope that only SS and SN are bad

[tom66]

Re: Panasonic P42X20E 4 red blinks

I'm talking about both of these connectors on the SS.

Disconnect both and SS power.

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Removed both flex and the power on SS still 0V on both Vs connectors

[tom66]

Re: Panasonic P42X20E 4 red blinks

Measured at PSU or SN?

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Every time at PSU

[tom66]

Re: Panasonic P42X20E 4 red blinks

OK, it could be a power supply problem. I'm trying to think of a good way to test it. Can you get old of a 60W or 100W incandescent light bulb rated for 230/240V operation? Touch it across the Vs terminals, and if it goes dim (try to test Vs voltage while doing this) then the PSU is at fault. It's a bit new to me. Some Panasonic plasmas don't power up when boards are unplugged too, which makes troubleshooting difficult.

[V3dran]

Re: Panasonic P42X20E 4 red blinks

Yup I have a light bulb 100W 230V
But I don't understand how to test it.
Should I connect the active and the neurtal terminal of the light bulb with two wires on the connector on the PSU?

Anyway what is sure is that if I remove both powers (SN and SS) I get 200V on both connectors, if anyone power is connected I get 0V on both connectors...

[V3dran]

Re: Panasonic P42X20E 4 red blinks

I found this manual
As I understand the command 10 PANEL MAIN ON on the slide 27 is not applied

[tom66]

Re: Panasonic P42X20E 4 red blinks

Yup I have a light bulb 100W 230V
But I don't understand how to test it.
Should I connect the active and the neurtal terminal of the light bulb with two wires on the connector on the PSU?

Yes, see if the bulb lights up. It will be a little dimmer than at 230V AC but should be lit brightly. If possible, test the Vs voltage at the same time. It seems either both boards have faults (unlikely in my opinion), or the PSU is incapable or some how it won't work if just one is unplugged (some kind of lock out.)