It all started on the VCFED forum many years ago, where people were looking for help on repairing their KIM-1 computer.
A dead KIM-1 is no easy to troubleshoot, most ICs are not in IC sockets, so poking around with a scope is looking for dead signal lines is all you can do.
But if the 6502 is working, programs could be written to test parts.

So Dwight Elvey designed and programmed a diagnostic board for the KIM-1, to determine what might be wrong with this KIM-1.
The board switches off the 6530 ROMs and one can run tests on the onboard ROM, looking for for defective RAM, defective LED display, defective 6530 ports.

Here I present the complete design of the board, with help and permission of Dwight Elvey, Santo Nucifora and Liu Ganning.
In October 2025 I have revised the page, build a diagnostic board myself and added the reverse engineered sources of the tests in MOS Technology standard assembler syntax instead of the obscure Forth like assembler Dwight uses. The EPROM can now be build and modified with modern tools.

The board has been used by many with success. The usual suspect, the 6530-002 RRIOT, was not always the problem maker. Defective RAM IC, a TTL IC with dead ports and such also were found
by using the test programs to pinpoint the area to check.