VC-20 / VIC-20 Diagnostic Cartridge

Tests:
  • RAM TEST
  • COLOR RAM TEST
  • ROMCHECK EF
  • ROMCHECK C0
  • Keyboard Test
  • Serial Bus
  • Zero Page
  • Stack Test

Keeps a running track of Days/Uptime & Total Cycles Run.
Does appear to be an offical Commodore item
((c) Commodore 1980 on PCB inside and Commodore Logos onscreen)