One of the very common problems with KIM-1 computers is that one or both custom programmed 6530 chips fails. They haven’t been made since the early 1980s and are basically impossible to find (not even eBay has them). Lots of people talked about making a replacement using the common 6532 and external EPROM, but nobody published a working circuit. After hundreds of hours of pointless searching, I finally decided to just design one and post it so anyone can use it.
KIM-1 6530 Replacement
My ugly breadboard:
I got it working and tested earlier today and am working on a PC board. The design is free for anyone to use, as will be the PC board design once done. I’ve only used it to replace 6530-002 (U2) but the design should work for the 003 device as well. If anyone uses it for 003 let me know.
A PC board was finished and prototypes were ordered.
I’ve been quite busy doing things behind the scenes, but the revised version of the KIM Multifunction board was finally ordered. Boards should arrive in a couple weeks, and given the debugging time spent on the first revision, it shouldn’t take too long to get boards built and tested for sale.
Another project has been to restore a partially working KIM that’s been on the bench for years. It is needed to have two KIMs set up to demonstrate all the boards at upcoming shows.
I’ve spent some time debugging the new KIM Multifunction board this week. These are a couple shots of it on the bench. One chip was piggybacked onto another and a few jumpers added here and there:
This is taken directly overhead, showing the two new motherboard pieces and the multifunction board plugged into the first slot:
As of right now (1/21/2017 evening), everything on the new board works except for the EEPROM. It decodes fine, but the bus transceiver isn’t driving the data bus. The updates to fix the problem were made on the schematic, so tomorrow morning there will be a few more cuts and jumpers. It looks like no additional parts will be needed but the circuit design is enough that I don’t want to sell these with so many cuts and jumpers, and will do a second spin.