Conquered springs in 1053 console, more work on SAC interface enhancement

1053 CONSOLE PRINTER RESTORATION

I continued to wrestle with the spring that unsprung, trying to get it securely over the tang of the interposer from which it popped. I do have just barely enough access for a springhook, but I am limited by my back's capacity to spend time hunched over at exactly the angle where I can see what the tool is doing.

Finally, by mid afternoon, I got the pesky spring back on the tang. It took many short outings, each time after I felt fresh and ready to tackle the spring once again. I verified that all five interposers work properly so it was time to reinstall the operational magnet assembly.

Operational magnet assembly in place but missing pivot arm on right side

By dinner time, I had the operational magnet assembly installed. However, when tightening up the pivot screws for the two arms that provide feedback thru a microswitch when an operational cycle occurs, I had the screw snap off. Of course the screw is not found in an ordinary selectric models or in the other selectric mechanism from the Dura word processor, it is unique to the IO Selectric.

Pivot arm with screw which snapped off at nut on left

I will need to check with Grainger to see if they have a compatible screw, otherwise it will have to be made on a lathe or built up out of multiple parts. Here I thought I would be running the diagnostics tonight. I had three of the five pull links already attached so it was nearly ready.

Remaining tasks for the console printer:

• Attach remaining two pull links
• Check and adjust pull links
• Check and adjust carrier return torque
• Repair nylon ribbon color tape
• Attach and adjust ribbon color tape
• Verify correct operation before adding covers
• Install tab clear/set linkage on front plate and mechanism
• Put cover over typewriter and fasten
• Place printer in its normal position on the machine

SAC INTERFACE FOR ADDING PERIPHERALS TO THE 1130

I installed the female connector on the IO panel at the bottom right rear of the 1130 and hooked up the cable. It was time to verify the continuity of all the lines between the SAC Interface box and my daughter card up in the 1130 near the usage meter.

Small card at top left to handle interrupt level 0 & 1 signals

Small card at top right, another view

All is good on the lines, so time to finish up the parts inside the 1130:

• Mount the daughter board to the frame
• dress the twisted pairs to their target locations on gates A and B
• trim and install push-on connectors to the twisted pairs
• install push-on connectors to 1131 backplanes
• mount emulation engine and relay boards
• trim twisted pair and attach to emulation engine
• wire relay boards to 1130 panel buttons
• connect twisted pairs into fpga in the SAC Interface Box
• set logic in fpga to make use of interrupt lines and emulation engine
• test emulation engine with bench power supply
• test SAC interface lines with bench power supply
• develop mount for DC-DC converter and prepare wires to +6V
• wire in DC-DC converter and retest all functions

As you can see, there are quite a few steps, even if each one is relatively short, this can add up to hours of work. I spent time at night documenting all the assignments, wiring and approach.