I am currently on vacation and the products from my shop will be unavailable for the next few days.
Thank you for your patience and apologize for any inconvenience. The shop will re-open on 20th Aug 2022

VIC-20 35k Memory expansion


Category: Tag:

VIC-20 35k Memory expansion

PCB comes assembled with:

  • Custom PCB (Colour will either be green or blue)
  • IC1 – HY62256, 32Kb static RAM
  • IC2 – HY6264, 8Kb static RAM
  • IC3 – 74LS21
  • RN1 – 8 way resistor network 10K
  • SW1 – 8 way DIP switch
  • IC Sockets

This is a custom PCB based on the schematic from Ruud Baltissen


DIP Switch Settings:

  • all off – Expansion Disabled
  • 6 ON – 4607 free
  • 6,7,8 ON – 6655 free
  • 5 ON – 11775 free
  • 4,5 ON – 19967 free
  • 3,4,5 ON – 28159 free
  • All ON – 35k

Warning: Do not plug/unplug any expansion card while the computer is on. You risk damaging the computer and the expansion card

The PCB connects to the expansion slot and by selecting various jumpers you can enable up to 35Kb of memory for your Commodore VIC-20.

At bootup the VIC-20 will only see 28k of memory. (So this is expected when booting up) The remainder of the memory is available and can be addressed via software.