The control PCB
The control circuit only needs a small PCB that finds an easy place inside the HP14570. The +5V power comes from one of the group boards. Three flat cables link the switching outputs to each of the three Group boards.
The control signals are active low and the HP14570 control inputs have pull-ups, so to switch on an output you pull the corresponding control line low. For group A that is done directly through the PIC. As I wanted a galvanic isolation with Group B and C, I used opto couplers and pull-down transistors for those.
One issue is the connections to your switched mains outlets. The original '14570 had proprietary connectors that actually fit all 12 on the 19" back panel. Mating plugs are pure unobtanium. That means you have to use your creativity. I am currently putting together an external extension strip with a thick umbilical cable to the '14570 with switching wires for all 12 outlets. Ugly, but effective.
In parting...
If you are lucky enough to get yourself an HP14570, you want the service manual as well. You can get a .pdf version at ArtekMedia. High quality scans for a reasonable price. Tell them I send you.
I can provide you with the software to program the PIC microcontroller. I may also have a spare PCB left. Mail me.
