Finishing wiring of the console panel lighting power, tested and closed up fpga extender box for other 1130

IMPLEMENTING FUSE FOR THE LIGHTING PANEL POWER SUPPLY

I disconnected the feed to fuse F7 which was fed from the 230V line after the power contactor. The various fuses have wires with terminal rings that daisy chain the power between the fuses that share a source. By moving one wire that runs to F7, taking it off F2 where it was tapping the 230V supply and moving it to F6 which is tapping the T2 115V supply, I 'converted' the fuse to a 115V feed which can go directly to the terminal block to connect to the lighting power supply.

The only change that needed to be made was to swing the common side wire from where it was placed on the terminal for the 230V common and move it one down to a common for the 115V out of T2. I now have a properly fused supply that will be getting 115V when the machine is powered up.

TESTING SUPPLY AND OUTPUT VOLTAGE OFFLINE

I wired up a temporary plug to 115V with a 1A fuse and wired it to the power supply, having disconnected the wires from the 1130 power distribution box. This allowed me to fire it up and verify the correct operation and output voltage before I hooked it to the system.

Indeed, the supply worked without blowing the fuse and produced a bit over 7.25VAC on its output. All appears good so I proceeded to wire this into the machine, put in fuse F7 and power up the 1130.

VERIFYING LIGHTS WORK ON DISPLAY BOARD

Once this was up and running I hooked up a small bench supply to deliver 3V through a 6.2Kohm series resistor to various lamp input pins of the control board. I of course verified that the black terminal of the bench supply did not carry a voltage relative to the lighting board common terminal, since that is the return side of the 3V I will inject. 

I found about 15VAC across the grounds, clearly something picked up from the neutral side of the AC supply to which the bench supply was connected. I quickly solved that problem by putting in the fuses to active T3 and the convenience outlet. With the bench supply plugged into that outlet, I have isolation of ground and could wire the 'ground' or return terminal of the bench supply to the shared ground in the lighting panel circuit.

When I touched the 3V fed through the resistor to various signal pins, the lamps lit exactly as expected. I feel confident that most if not all will display when I get the +6V supply repaired and back into the machine. 

FINISHED CONTINUITY TESTING OF CABLE CONNECTORS TO THE FPGA BOARD

My FPGA based extender box connects to my IBM 1130 using the Storage Access Channel cables plus an augmented set of functions I added on a separate cable. I finished up the testing of the wiring and closed up the box. Next steps are to move it over next to my 1130, and cable it up.