Last Updated on September 29, 2019 by Dave Farquhar
The VIC-20 was on the market for about four years, but that was long enough for Commodore to revise it several times in pursuit of lower costs. Here’s a look at the various Commodore VIC-20 models.
The VIC-20 was quickly overshadowed by the Commodore 64, but if anything, that means the VIC-20 provides a more affordable challenge for collectors than its more common sibling. Despite its shorter time on the market, the VIC-20 has numerous variations for collectors to pursue.
The Commodore VIC-20 keyboard
Perhaps the most obvious, visible difference in the various VIC-20 variations was the keyboard. Early VIC-20s had a squared-off, PET-style keyboard that looks very distinctive compared to the more common keyboards we see in breadbin-style 64s. Later VIC-20s had a 64-style keyboard. Calling it 64-style may be a misnomer, as the two keyboards are completely interchangeable.
Commodore VIC-20 label variations
Much like the C-64 and its coveted silver label, the VIC-20 also had various label revisions. The VIC actually has three styles of label to chase.
The earliest version has a silver background with dark brown text, much like the labels Commodore used on its PET computers and associated equipment.
A later version has a silver label with rainbow text, perhaps to emphasize that the VIC-20 had color in an era when many computers did not.
The last and final version of the VIC-20 label was the rainbow label, much like the most common C-64 variant.
Commodore VIC-20 motherboard revisions
Commodore changed the VIC-20 motherboard three times. The early revision A system board was present in all silver-label VIC-20s. It contained 10 512-byte SRAM chips.
The revision B board, also known as ASSY 324003, also contained 10 512-byte SRAM chips.
The later Revision D system board, present in rainbow-label VIC-20s, has a curious change. It has a pair of 2048-byte chips plus three 512-byte chips. This was required for addressing. Effectively it wastes 512 bytes of RAM, but it was cheaper to waste 512 bytes than to continue shipping 10 chips. In a further curiosity, this board version had a lower number, ASSY 250403.
Why not increase the amount of system memory? Compatibility. When you added memory, the VIC-20 changed its memory map, which could cause compatibility issues with software designed for the unexpanded 5K VIC. While Commodore probably could have increased the onboard memory to 8K while increasing the price very little, if at all, the compatibility issues would have doomed it.
Commodore VIC-20 models
There are three major models of Commodore VIC-20:
- 1981 model: Rev. A system board, silver label, PET-style keyboard, 2-pin power supply
- 1982 model: Rev. A or B system board, silver label, C64-style keyboard, 2-pin power supply.
- 1983 model: Rev. D system board, rainbow label, C64-style keyboard, C64-style power supply with same pinout but lower amperage. Use of a replacement 64 power supply is recommended with this model.
The 1982 and 1983 models are more common than the 1981 model. Sales tailed off in 1983 but Commodore continued to sell the machine into 1985. They sold 800,000 units in 1982 and 2.5 million units total.
Commodore released several international versions of the VIC-20. Versions for sale in Sweeden and Japan had a character set for those markets. Versions for sale in the United States used NTSC video, while versions for the rest of the world used the PAL standard. Commodore also released a version for France that used the SECAM standard. Perhaps most famously, German versions were called the VC-20 because the word “vic” is obscene in German.
Repairing a VIC-20
The VIC-20 has fewer proprietary chips than the 64 did, so replacements are more readily available. That said, the VIC is pretty reliable anyway. Here’s an easy fix for a color issue, which is the only problem I had to fix in mine.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.