Flip Chip Tester(s)

Over the years, there has been an ongoing interest in a way to test the flip-chip modules from which various DEC gear, including several models of PDP-8, are made. Here's a sort of reverse timeline of related projects that I have worked on:

RasPi 0W Variant of Stearn's Tester

I did some additional work to connect Warren's tester to a Raspberry Pi 0W, which fits in a nice box and connects via a wired interface or SSH to the user's console. The page describing the changes is here.

Windows Variant of Stearn's Tester

Michael Thompson of RICM has done some nice work towards getting Warren's tester to work connected directly to a modern Windows desktop. His solution uses an FTDi USB to SPI cable, and his source, etc. can be found here.

Warren Stearn's Tester

Some years later (2012?), Warren Stearns developed a flip-chip module tester, and began travelling the United States, testing and repairing modules as part of restoration projects, notably for RICM and most recently UMD. I made an effort in 2014 to capture Warren's design, and here are photos of his prototype from that time:

Component Side

Wiring Side

Unfortunately, Warren passed away suddenly in 2017. His loss was deeply felt, and there is also a strong feeling in the community that it is important to continue his efforts.

In early 2018 Doug Ingraham made available the software (and module test vectors!) that Warren had used to run his tester. I decided to produce a PCB of my attempt to capture the hardware of the design. Along with the software from Doug, it was hoped that we could commemorate Warren's work and make testers available for those who need them.

Warren had added headers for various supply voltages to his prototype over the years, and my drawings differ in the orientation of some components, a couple of blue wires, but this effort has been largely successful. Working testers have been created!

Tester board designs can be found here, and software here.

Blue wire information and important assembly tips and hints for the kits are available here.

6809 Based Tester

In 2006, Henk Gooijen and I collaborated on a tester, which is beautifully documented on Henk's site here.

This tester, like most efforts so far, focuses on positive logic modules, and lacks capabilities for testing negative logic or analog features when they occur in flip-chip modules.

Unfortunately, the project languished for many years, lacking for software to conveniently run it, and test vectors for complex modules.