This thread will be my repository for my Keithley 228 and Keithley 228A source meter. The first section of this thread is going to look at reproducing the PCB for the input section. Photos "A - S" are of the PCB that is being used to recreate the board. I have started the project in EasyEda and it is "public" so anyone can view, copy, and get them made on their own. The current version, V1, was done in hast and I half-assed it by not designing in the original screw-terminals (thank you bitseeker for parts links and calling it to my attention). I will finish the board shortly and post the link here along with the screw terminals parts links.
If I missed anything in the pics below, please let me know and I will fix it. If you have one of these units and my PCB is different than yours, please share pics as well.
In the next section of the thread, I will post complete tear down pics and compare the 228 and the 228A side-by-side.