Panasonic TX-26LXD8 stuck in standby.

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

Pictures of PSU.

I have two PSUs for this T.V. The previous owner bought one to try to repair it and had the same symptoms. I tested the PSUs and ruled them out, as both are outputting the correct voltages shown going to the main board and inverter on the SCH. The don't change under load.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

Vin is HI/LO, that what I expected. You will have to look at the diagram and find out what that resistor is hooked up to, I will have to find time to look through the service manual to find out.

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

I am busy trying to do that for you on the SCH, to go with the pic of the location on the rear, needless to say, brain pain, lol.

That point leads to Q1104. It goes around the edge of the board under the yellow bar that is printed on it.

Edit - Third pic is location of Q1104 on the board.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

OK, this is waht I found in the SCH. I think the TV is sensing something wrong, but I am not sure whay you are not seeing any error lights per service manual.
The AG_TV_SUB_ON is going HI/LO must be due to the fault some where, it is generated by IC 1100 PIN 52. Please look at the power LED again to see if you see nay blinking pattern. We may have to start disconnecting boards.

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

The power LED comes on then goes off again, definitely no error codes shown.

With just power coming to the mainboard from the PSU and with the power switch connected to mainboard (no other connectors connected) Pin 52 of IC1100 is going Hi-Lo. Don't know how helpful this might be.

Same goes for Pin 18 TP of IC5604 - AG_TV_SUB_ON is Hi-Lo. (I know realise this is obvious by what you wrote)

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

I tried to to understand what's going on at IC1100 and it has led me to check IC1104 (Reset IC).

Pin 1 should be 3.3vdc - Pin 1 is 2.6vdc stable
Pin 2 should be 24vdc - Pin 2 is 7.2vdc stable

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

At tis point I do not know why that micro controller IC 1100 output pin 52 is going HI/LO.
I need to uderstand more on how this micro controller operates. I wonder if other output pins of this micro controller are doing the same thing.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

I wonder where that 24v is generated from the main power supply, can you look at the power supply board and see if it has 24vdc output connector, the 24vdc is usually used for the backlights inverter board, not sure if this 24vdc on the IC1104 is the same 24vdc for the inverter board.

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

Pics of PSU are in post #21.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

I can see 3 relays, do you hear them click at all?

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

There is 24vdc at the area circled in red (see pic) but only 2.6vdc at pin 1 and 7.2vdc at pin 2 of IC1104.

Could the problem be that first resistor where the 24vdc is coming in?

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

I can see 3 relays, do you hear them click at all?

Yes there is clicking coming from one of them.

24vdc enters the mainboard at connector A7 on pins 7 and 8. There is a separate connector for the 24vdc going to the inverter.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

"24vdc enters the mainboard at connector A7 on pins 7 and 8." So are you getting 24vdc at these points or only get 7.2v?

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

24vdc at these points.

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

Do you think the problem could be the resistor I mentioned in post #31?

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

No, may be the IC is loading it down, I did find much of the info on this RESET IC yet. Can you read the P/N as printed on it?

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

It reads - 3C08Q

Panasonic P/N is - C0EBM0000026

[py3m4n]

Re: Panasonic TX-26LXD8 stuck in standby.

Here's a pic of the SCH for IC1104 and a pic of the block diagram where I got the voltages from.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

OK, I see two voltage divider resistors 10K and 22K, so with 24V inputn the IC will get 7.5vdc at input pin2 feeding it which is correct as you have measured.
Not sure if the output pin is supposed to switch LO then come back up HI after the reset is done.

[budm]

Re: Panasonic TX-26LXD8 stuck in standby.

Take the voltage reading at PIN 1 when TV is first plugged into the outlet and also the power switch is activated, I want to see the output change state or not,