Sharp LC-60LE550U Mainboard F905FM06 DUNTKF905WE06TV Main board keeps dying

[m4a2t0t]

What would cause a main board to die when you disconnect AC power to the TV?

This is the second board that it has happened with. All I am doing is disconnecting the power cord from the wall and plugging it back in.

I replaced the main board because I was not getting a signal on PS_ON when pressing the power button. The PSU was/is still sending its 5v standby signal

Thanks

[lotas]

Re: TV Main board keeps dying

What brand, what model, what motherboard?

[m4a2t0t]

Re: TV Main board keeps dying

Sharp LC-60LE550U
Mainboard F905FM06 DUNTKF905WE06/

[lotas]

Re: TV Main board keeps dying

The firmware could have crashed, if Hdmi sources were connected, then the controller (processor) could have suffered.

[m4a2t0t]

Re: TV Main board keeps dying

No source was connected.

When I plug in power the front panel light turns on for less than a second and then turns off. Would bad firmware cause this symptom?

[lotas]

Re: TV Main board keeps dying

Yes, there may be a problem with the firmware.
But first, check all the supply voltages on the DC / DC converters.

[Diah]

Re: TV Main board keeps dying

No source

hey man.. we are still being human depending on our memories not like dummy Microsoft GPT AI machine... post photos of yours main boards and all together so we can bring the memories bock to tell where and what we found on this and that. LOL

[petehall347]

Re: TV Main board keeps dying

surge from power supply would do it

[m4a2t0t]

Re: TV Main board keeps dying

surge from power supply would do it

How often do you see a PWB cause a surge only when power is removed?

I uploaded the service manual and an image of the PWB if for whomever needed it. TCON and Main board pics and schematics are in the manual so I didnt add them. PWB wasnt in the manual.

[m4a2t0t]

Re: TV Main board keeps dying

edit: I reconnected the supply and have all voltages now

[nomoresonys]

Re: TV Main board keeps dying

If you are too lazy to post pictures, then I guess I'm too lazy to help, definitely not going to dig and stumble thru a manual just to see a picture: https://www.badcaps.net/forum/showthread.php?t=39740

[nomoresonys]

Re: TV Main board keeps dying

That may seem a little harsh but decent pictures are what is needed and always a good starting point when troubleshooting.