Chosen Solution

I have a Sony XBR-65X810C 65" TV that was initially stuck in a boot loop. Initially the TV was shutting on and off randomly and not displaying video from our dvd player but was playing sound. Then it got stuck into a boot loop so whenever the TV was plugged in, it would turn itself on, show the android booting animation, then crash and restart the process. Last week I took it into a TV repair store and I was told I needed to replace the main board. I decided to do the repair myself since I have a basic understanding of electronics repair and didn’t want to pay several hundred dollars for the repair. I ordered a replacement mainboard (model number A-2072-555-C) from a 3rd party website. After installing it the TV will no longer turn on at all. Even the bottom white bar that lights up won’t light up. I tested the 3V standby pin leading to the mainboard, and it was 3.4V so I’m not sure what my issue is. Any ideas on what I can do to fix this, or do I need to replace the powerboard as well?

Hi, Here’s some images taken from the service manual for the TV showing the No Power troubleshooting flowcharts.

(click on images to enlarge for better viewing) Hopefully this is a start