A very common problem with maintaining 40 year old computer systems is that some of the parts have not been made for many decades, such as the two 6530 chips on the KIM-1. Each contains several timers, 64 bytes of RAM, multiple parallel I/O ports and 1K of mask programmed ROM containing the KIM-1 monitor program. To make things even more complicated, each 6530 is mask programmed with a number of configuration options such as which interface pins and address lines select which internal devices.
Many people, myself included, have at least one KIM-1 in their collections with a non-functioning 6530. Depending on what failed, the KIM might be quite usable, completely unusable, or someplace in between. For these people, there was little chance of ever fixing the problem because the two 6530s in the KIM are unavailable anywhere… not even on eBay! While some people have created work-alike versions, none of the schematics or results ever became publicly available.
In an effort to fix my own KIM, I borrowed work of other people and developed a small board that can replace either 6530 on a KIM-1:
Basically this emulates the functionality of the non-functioning 6530 by using the I/O ports, RAM, and timers from the 6532 chip, and then having an external EEPROM hold the code that was in the ROM of the original chip.
The board replaced U2 (6530-002) on my KIM and produces a fully functional system again. This is a prototype board (strange board color) but is identical to the production version otherwise:
For full documentation, schematics, design files, Gerbers, EAGLE CAD files and other technical data please see my development notes.
If you don’t want to build your own version from my schematics, Corsham Tech does offer three options:
- Bare Board
The bare board is just the board. Documentation is on this page. It’s mailed in a small envelope and can be built with commonly available parts.
This is the first kit we’ve ever offered, and includes the board and all parts but minimal build instructions. It is assumed you know how to read schematics, can identify parts, and can solder the parts to the board.
The assembled version is, well, fully assembled. This is the quickest way, and the easiest. Just set the three jumpers to either U2 or U3 to indicate which chip you’re replacing, remove the old 6530, then plug in this board. I strongly suggest saving the original 6530 in case you ever decide to sell your KIM to a museum as a static display.