I have a good, working Apple ][+ that I have used to verify a disk ][ drive and controller. I got an a new-to-me ][+ from my dad's attic. It will boot to ] prompt with no cards inside. When I instal the controller into slot 6, and single disk ][ drive, it attempts to boot on power-up, and does the seek to track 0 clackity-clack, but never boots a known good diskette.
Any ideas what on the main logic board I can look to repair/replace?