[Panasonic Lcd TX-L22X20E] 7 blinks of death

[Dumah Brazorf]

Hi,
tryin' to fix this tv. 7 blinks of death are common on Panasonic but all the discussion i found are related to plasma and/or big tvs.
This 22" tv is most like a monitor, only 2 boards.
So far I disconnected all cfls and the ribbon cable to the monitor but no change.
Caps tested with esr meter have a resistance below 0,20ohm so i think they're ok.
The main problems is that i can't figure out if it's powerboard related or it's the video board.

[tom66]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

This manual might help:-


7 blinks: SUB 3.3V SOS

It is for 32" minimum, but 22" main board might be the same with only minor differences.

You would need schematic of A board and find 3.3V supply, then try to figure out why it is low.

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

Thanks, i give it a read.

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

I found some smd capacitor shorted on the "A" board. There are 4 groups composed by a sp8k1 or sp8k2, an inductor and 3 caps. I post an image of these groups. I found a cap shorted in 2 of the groups. It's very difficult to desolder smds without damage the pcb underneath.
The tv now works but shuts down after a couple of minutes keeping the green led. Not only cfl power off, also the image goes away.

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

From these groups I have 5V, 3,3V, 1,8V and 1,2V. Power led blink green then solid but i have no more image nor backlight.

[tom66]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

Well, if you remove a cap, you change the behaviour of the circuit. Who knows what that could do to the output when it gets hot or more current drawn?

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

It seems a power issue. I see the audio optical light turn off and on when it try to start. If I let it powered sometimes it fires up and work for few minutes.
I had only 10uF at home but I think it needs 22uF. I'll buy some.

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

Well, this morning I played again with that smd capacitors and removed one of mine.
The tv had the same behaviour (try to start and fail in loop). Then I pressed the heatsink to ensure that it make contact with the main processor. Now has been working for two hours...
Don't know what to think...

[ben7]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

Well, this morning I played again with that smd capacitors and removed one of mine.
The tv had the same behaviour (try to start and fail in loop). Then I pressed the heatsink to ensure that it make contact with the main processor. Now has been working for two hours...
Don't know what to think...

Then it's an issue with the solder balls on the main processor.
Looks like you'll have to buy a new board, unless you know, or know someone else who can re-ball that chip

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

I have a heatgun and some liquid flux, if (or when) it fails again (6 hours working) I'll give them a try.

[Dumah Brazorf]

Re: [Panasonic Lcd TX-L22X20E] 7 blinks of death

Well, it failed again half an hour after I mounted the rear cover.
The heatsink chip runs hot so this time, after a vigorous reflow with liquid flux, I added a 5cm fan @5V, barely udible a few inches distant.
Watched a couple of hours fully closed yesterday evening. Let's see in the long distance...