I've been having that issue too, it seems to be the ground wire that gets loose and doesnt light up the display. I opened mine up and wiggled the wires and pressed them in and it seemed to work.

yes been through that exact routine multiple times, then eventually stopped working entirely, hoping someone has one they aren't using.

post a WTB *want to buy* add in the classifieds section.

I always try the wiggle and slap and tickle first

if that doesn't work, I guess check the grounds and all connections.

Also use the search function: Post number 2 and 4 on thread may help
https://www.dsmtuners.com/threads/apexi-safc-power-no-screen.400170/

https://www.dsmtuners.com/threads/apexi-safc-screen-dosnt-work.189522/