Main head unit blank, went off for a day last week then came back on the next so I didn’t worry about it until now , now it’s not coming on at all.

Things I’ve tried:
Took negative off and replaced
Took both positive and negative off for 15 minutes also , tried reset by touching them together after disconnecting.
Also removed fuses, 1,68 and 64
Still not coming on

Any ideas what to check now
Thanks


* Update just came back on 2 hours battery off