Chime but delayed display
We got an imac in that chimes on power on but it takes 10’s of minutes before we actually see anything on the display.
Sometimes it will attempt to boot from the internal drive (we end up seeing an apple logo and loading bar) but it just restarts.
After trying to go into the boot menu (option key) and not getting anything on the screen, we left it alone for a while and it automatically booted into a catalina based recovery mode. We tried plugging in an external tester and can see it in disk util, but cannot see the internal drive listed there.
When we try to install an OS on our tester, it says we don’t have the firmware to do so so.
Before we open this one up (adhesive based), is this looking like a logic board issue or could a bad internal drive cause this type of behavior?