Panasonic TX 58-AXW804 will not turn on

[Samui67]

Dear guys,

i have a big issue with my Panasonic TX-58-AXW804 TV.

If i plug in the power cord, the power board relais is always clicking. So i guess this is related to the safety protection circuit.

If i press the power button on the backside of the TV for several seconds and release it afterwards, the clicking stops and for around 2 seconds the Panasonic logo stays on the screen. But after this 2 seconds the clicking starts again and the screen is switching off and not switching on again.

I am mentioning, that the trouble is related to the A-Board. I meassured the voltages on the testpoints of the A-Board and the 3.3V, 5V and 16V are there. But related to the protection circuit they are turning off in the same cycles like the relais of the power supply board is switching.

The red LED is always on until i switching on by the way i described. Then the green LED is flickering fast during this 2 seconds and after this the red LED again is always on.

I highly would appreciate any help for can solve the issue. Thank you very much in advance.

[nomoresonys]

Re: Panasonic TX 58-AXW804 will not turn on

Simple things first, check all the diodes, check the solder joints on the bottom of board, look closely at solder joints of components on heatsinks and transformers. As always BE VERY CAREFUL when working with powerboard, DEADLY VOLTAGE on HOT side.

[Samui67]

Re: Panasonic TX 58-AXW804 will not turn on

Meanwhile i checked the Power board for bad solder points, diodes, transistors and caps. Everything looks perfect there. The same i did for the A-Board. No bad solder points or damaged caps or diodes. Of course it is not possible with the equipement i do have to check bad contact points under the emmc or cpu chips.

What makes me crazy is that i have no chance for getting into the service menu or even having a stable power on situation. 2 seconds after the special procedure i described, the lcd panel is not switching on again, just a continious red led and the clicking of the Omron power on relais.

[budm]

Re: Panasonic TX 58-AXW804 will not turn on

Can we see good clear pictures of the whole backside of the TV showing all the boards?

[R_J]

Re: Panasonic TX 58-AXW804 will not turn on

Does this work? it is from the service manual

[Samui67]

Re: Panasonic TX 58-AXW804 will not turn on

It was the first thing i tried. It doesn't work,
because of the fast switching off /on cycle of the relais.

After i did read so many messages with similar
issues, i disassembled the A-Board again and
brought it to a local Panasonic service station
for check and repair. The estmated costs are
between 150 - 200 Euro.

Unfortunately this A-Board is nowhere in Stock
anymore. I am really not very happy about!
The TV is just 5 years old.

[nomoresonys]

Re: Panasonic TX 58-AXW804 will not turn on

Unhook cable from powerboard to mainboard, check for steady voltage at standby pin of powerboard.

[Samui67]

Re: Panasonic TX 58-AXW804 will not turn on

I did what you said. Attached the part from the circuit drawing of the PSU output, the total view of the PSU board and the meassure point for - in my opinion - the standby voltage.
With the A-Board unplugged, i meassured 5.2V constantly and no any clicking of the relais.

[nomoresonys]

Re: Panasonic TX 58-AXW804 will not turn on

Maybe check the voltage regulators on the maibboard.

[Samui67]

Re: Panasonic TX 58-AXW804 will not turn on

Hi nomoresonys, i would like to say, now i am back to the roots...

Of course, i could meassure the voltage regulators on the mainboard (A-Board),
but even one of them is damaged and i would get this part for spare, i have not the equipement for the replacement.

All the parts there (front- and backside) are placed by surface mounted technology.
Especially, if the damaged part wouldn't be a voltage regulator. It also easily could be related to a broken flash or emmc chip....

So i have to go the pity hard way now and send the board back for repair
to Panasonic. Like i wrote, nowhere is a spare board available for a just 5 year old TV!

Maybe i should change my nickname here into "nomorepanasonic"