Daves Old Computers - Commodore Vic20

The Commodore Vic20 was an attempt to introduce a very low cost home computer which also functioned as a game console. It was severely limited by its having only 4k of RAM, however due to its low cost it sold very well, and Vic20's are very common.

Rumor has it that the machine was created because Commodore had a surplus of "VIC" graphic chips that were not selling well. The VIC-20 was a lost cost consumer product designed to take advantage of this surplus inventory.

Shortly after the VIC-20, Commodore introduced its big brother, the Commodore 64. Although it used the same CPU, the C64 was not really software compatible with the VIC-20, but it did use the same serial peripheral bus, allowing VIC-20 owners to upgrade to the C64 without having to buy new peripherals.

Click any photo to view a large high-resolution image.

Complete Commodore Vic20. Clockwise from the top:
Back of Box, Front of Box, Vic 1541 disk drive, 1541 disk drive, Commodore RF modulator, Vic20 main unit, Vic20 Cassette drive, Pair of Vic20 joysticks, Vic20 power supply.

The top unit is actually the older/first revision. The bottom unit is the second revision. Note the difference in the labels.

Vic20 back panel. Left to right: Cartridge slot, Audio/video out, Serial peripheral port, Cassette interface port, User (modem) port.

Right side view. Left to right:
Game (joystick) port, Power switch, Power socket. Note the older unit (top) uses a 9v AC connection, while the newer unit uses a regulated DC connection which is the same power supply as the Commodore 64.

Information label on bottom of Vic20 main units.
Left: First edition unit, Right: Later unit.

The Commodore Vic20 cassette drive. Unlike many other home systems, the Vic20 required a special tape drive.

Top: Original white VIC-1541 diskette drive (single sided - 180k).
Bottom: Later editions of the drive were changed to Commodore 64 colors and the word "VIC" was removed from the front label. The rear information label of this drive still reads "VIC-1541". Still later versions of the drive removed all traces of the "VIC" name (See my Commodore 64 page).

Rear view of diskette drives. Note the dual connectors allowing daisy chaining on the serial peripheral bus.

Original Commodore documentaion for the Vic20's and diskette drive.

Some Vic20 software cartridges. Note the large cartridge in the upper left corner. This is a "double ended" cartridge which was actually two separate cartridges in a single enclosure - you turned it around to select the other game.

The Commodore Plus/4 is considered by some to be the successor to the VIC-20, however this machine released in 1984 is a different machine, although much like the VIC-20 and Commodore-64 in some ways. It main feature is that it includes four built-in application programs. The built in apps. were "unspectacular" and the machine was unsuccessful in the marketplace. Donated by Bill Mckinnon.

Views: Keyboard, Back, Bottom.

Commodore VIC20 users reference (150k ZIP'd TXT)
Commodore VIC20 troubleshooting tips (18k TXT)
Commodore 154x disk drive service manual (15M PDF)
Commodore 1702 monitor guide (8k ZIP'd TXT)
Commodore cassette manual (8k ZIP'd TXT)
Commodore simulator
Commodore VIC20 advertisements: One, Two, Three.
The Commodore VIC20 - Byte May81 (1.7M PDF)
6502 CPU Data Sheet (2M PDF)

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Copyright 2004-2005 Dave Dunfield.