Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

[nomoresonys]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Good work, probably should have just retested 753 in circuit after taking 752 out, 752 was probably making 753 test bad.

[heathloder]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Just wanted to provide an update to this thread after finally receiving my Schottky diodes in the mail.

Replaced D752 and re-soldered Q750A, and...

It worked! The TV powered on normally and booted up as expected. So, just to confirm, the issue with this TV was the 150V 5A Schottky diode labelled D752.

Thank you @nomoresonys, @R_J, @budm, @ngth82 and @brucetv for your assistance!

[nomoresonys]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Glad to hear it, thanks for the feedback, not always but sometimes it's just a diode.

[frica]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

+1

[edmusic]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Hello all, new to the page. I have the same issue with this unit. I checked the same diodes, they check out ok. Any help would be greatly appreciated!!

[heathloder]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Hi Edmusic. My assistance won't be nearly as helpful as the others on this forum with more experience, but I can at least offer similar insight to what was offered to me.

Realistically, the diode was not the first suspicion for failure on this TV. Without pictures of your boards or measurements on the LED strings/main caps/LED drivers, there isn't really a whole lot of help that can be provided.

If you follow the steps from the beginning of this thread (i.e. start with post #2 where @ngth82 mentions 5 things you can perform/test), then you will be more likely to find the issue with your TV. My "aha" moment came when I literally removed the suspected failed diode and respective FET from the LED driver circuit, and the TV's behavior changed suddenly.

Lastly, @brucetv mentioned earlier in this thread that he had several of these come in with either bad rectifiers or a bad LED: "Check D751A and Q750A on power supply and if they are fine replace those four rectifier diodes." and "We did one about 6 months ago. No error blink code but we did find one led shorted. We got luckier with the other two with diode replacement."

That being said, I think I was just lucky it was only a diode on my TV. Your issue could be anywhere on that power supply board, without knowing anything else about the TV.

Good luck!

[edmusic]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

Thank you , appreciate your response. I found some corrosion on some components. Cleaned them and reinstalled the board. Well, the tv came back to life. I am excited.

[heathloder]

Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights

That's incredible news, actually! Glad to hear that it didn't require any replacement parts. Thanks for reporting your solution back here.