Welcome to the Commodore Plus/4 Service Manual

This is the service manual for the Plus/4 and is based on scanned images at Funet.

The following technical notes (Techtopics issues) are related to this service manual:

• Troubleshooting aides
• Line definitions
• Engineering change: Four protection diodes added to the serial port

For further information:

• Commodore 16 and Plus/4
  • old-computers.com entry for the C16
  • Marc-Jano Knopp's peek to the C264 series, available via The Internet Archive
  • 264 series firmware at Funet
  • 264 schematics at Funet
• General Commodore information
  • Commodore B Series resource maintained by Edward D. Shockley
  • Commodore Computer - A Canadian site with a gallery, advertisement & documentation archive, and more
  • Commodore Curiosity Page available via The Internet Archive
  • The Commodore Knowledge Base and Secret Weapons of Commodore
  • COMPUTE! and COMPUTE!'s Gazette indexes & archives maintained by Kevin Savetz
  • International Documentation Project for Commodore Eight-Bits hosted by Peter Karlsson
  • The Transactor Online Archive maintained by Craig Bruce
  • Versatile Commodore Emulator VICE
  • Commodore International at Wikipedia