Sony KD-75XE9005 - all lights off

[amarzahn]

It started all with random restarts or the TV being on in the morning and ended with a sudden fail. The stand-by light is dark since then.

Since then, means the replacement of both power boards
- APDP-293B1
- APDP-158A1
and the motherboard
BMKS 1-982-022-31

Still no use. So it is obvious I must have overlooked a single simple fail that probably would not cost as much as I already spent.
I believe the TV should start even though the back is open?
I was wondering if the TCON could be dead. But because everything is completely dark the chances are slim.

Because of the size I am unable to transport the TV somewhere.
In my city is no service for Sony TVs available.

So I am pretty much stuck with my dead TV.

Maybe someone has an idea how to proceed from here.

Thanks for your support!

[dskall]

Re: Sony KD-75XE9005 - all lights off

Start with pictures of each board. Check and list voltages going from power to mainboard.

[amarzahn]

Re: Sony KD-75XE9005 - all lights off

Start with pictures of each board. Check and list voltages going from power to mainboard.

That is easier said then done.
I ordered new boards because I lack the knowledge and time to go through the boards wiring.
I added the detail pictures.
220V appears fine. fuses are all good.
stand-by power output is supposed to be 3,3V.
I measure 3,5V when the mainboard is not connected.
After connection, the measured voltage drops to pretty much 0
I have no idea why that is.

I added the details in red on the two connected boards.

Thanks for your support.

[dskall]

Re: Sony KD-75XE9005 - all lights off

Sounds like you have a short in the mainboard.

[amarzahn]

Re: Sony KD-75XE9005 - all lights off

Sounds like you have a short in the mainboard.

The thing is, I have all boards in duplicate. The mainboard was freshly supplied by Sony itself. I will ask the supplier for advice. But it is hard for me to proof it is faulty.
Thanks for your support.

[dskall]

Re: Sony KD-75XE9005 - all lights off

With the new boards did symptoms change or are they the same? Does standby drop simply from plugging in mainboard? What other voltages are you getting on connector to mainboard? Does power_on voltage change when pressing power button?

[nomoresonys]

Re: Sony KD-75XE9005 - all lights off

see if you have any voltage on the BL_ERR pin.

[amarzahn]

Re: Sony KD-75XE9005 - all lights off

With the new boards did symptoms change or are they the same? Does standby drop simply from plugging in mainboard? What other voltages are you getting on connector to mainboard? Does power_on voltage change when pressing power button?

OK, i tried to go through the details.
I disassembled all and but it together on my desk then the mainboard would start (S/PDIF-Toslink lit and powerboard clicks).
So I figured something is shorting somewhere on the panel.

I plugged every device together piece by piece.

Only when I connect the
Sony Wifi board J20H088
the mainboard will stop starting and it all goes dark.
Which is completely weird because I can not see any power modulating features on this Wifi board...

BUT:
The TV backpanel is lit, the S/PDIF-Toslink lights up but Google is still not booting up. So besides the Wifi bug there might be something else.
Maybe with all de-/attaching the cables I ruined some of the flat ribbon connectors for the LCD information of the TCON.

Any further suggestions?

Thanks again for your support. It really helped to get this going onward!

BTW: if I plug in the new mainboard I receive 5 red blinks. I am unsure if that is related to the firmware on the mainboard or if it actually means anything.

[amarzahn]

Re: Sony KD-75XE9005 - all lights off

Update towards the NEW MAINBOARD:
flashed current software on mainboard.
Now backlight panel is lit but no information on LCD panel shows up.
No startscreen. Only after the time booting takes I get this weird Sony Service Sound (chill out music stream), nothing else.
The Sony Sound is also shown in a couple videos.

If I plug in the WIFI board the whole TV shuts down immediately with the "all black" symptoms from before.

I will try to order new flat ribbon cables even though it is weird because if the TCON fails there would be 5 red flashes that I do not have...

[amarzahn]

Re: Sony KD-75XE9005 - all lights off

OK, the firmware update was tiresome but after a couple reboots it came up just fine.
I had to leave the WIFI module unpluged as it was short circuiting something on the mainboard. But I do not use the Smart TV functions anyway.

a $10 part causing a couple hundred $$ unneccessary self made repair.
I believe a professional service would have not figured this one out either...
At least that is what I tell myself ;-D

Thanks for your thoughts and support!
I will certainly be back with some issues in the future!

[dskall]

Re: Sony KD-75XE9005 - all lights off

Nice job. Good you kept with it and thanks for the update.