Xbox one X No HDMI in

A few months ago I replaced the thermal paste on my one X. Then the HDMI in stopped working. It worked fine before the tear down. What would cause this to happen? Also this morning when I turned it on the display was stuck at 640x480 and after a restart it was fine. I am in the insiders program and it updated yesterday. So I don’t know if that was the cause or the timer chip is going bad.

Could be the retimer chip gone bad

I was thinking the samething but wouldn’t it be bad or good no in between? Its working fine now but still have no HDMI in.

Could be a hardrive or retimer chip just grab a old hardrive and see if that works if it doesn’t it most likely a retimer chip

Please tell me what a HDD has to do with the HDMI in not working?