6-red - touchpad ← OK, it is clear you have the touchpad disconnected so fine.
All other green, so RAM OK etc.
BIOS CODE: 0xC5
We don’t actually know what 0xC5 BIOS code means, but a few people have seen that.
Some others have had some success with removing one of the RAM chips, so maybe one of the RAM sockets is bad.
So, maybe try getting it to boot with just one RAM chip inserted.