Last year I was able to accomplish moving my 99/4A, Speech and PEB assembly to an older PC AT case
Message thread HERE
With help from Tursi answering my questions I was able to work out a design (all hard wired) for a 2 port cartridge expander that plugs directly into the 4a cartridge port on the main board. With a flip of a 3PDT switch I can switch between the 2 ports. Installed a reset switch with it.
Well, I finally took some time to design an actual PCB for it. I had to design the 36 pin Eagle library for it too. I still need to design a small PCB (cartridge end that will be soldered to the middle of the board by a 90 degree pin header.
I still need to verify the board again and again. Once I verify all traces a few more times then I may send it off to Oshpark to get made.
Wanted to share it.
I have updated the photos to a smaller footprint as to reduce cost as well as space required within my all in one unit.
This will require a cartridge extension board. A simple 36 pin (18x2) board. This board will plug into the F3 connector that plugs directly into the 99/4a mainboard.
Added photos for my hand wired development board that I am currently using in my All-In-One PEB. I used 30 AWG solid core wire wrap wire to make the connections.
Edited by Shift838, Sat Mar 3, 2018 9:36 PM.