This is an old post, preserved for reference.
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A while ago I wrote an article about how, in the dim and distant past before I had a decent EPROM programmer, I had repaired a problem with a faulty VIC20. As well as a few corroded chips and bad connections, the Kernal ROM had failed. This was a 24 pin 8K mask ROM, and at the time, the only solution I had was to use a 27C64, a 28 pin 8K EPROM in a socket adapter. The result, although successful, was less than elegant.