Disk drive reconnection and one issue

WIRED UP THE AC POWER CABLE TO THE DISK DRIVE

The AC power cable was reinstalled in the disk drive, with the ground wire connected to the AC box lug and the hot and neutral wires connected to their spot on terminal block TB4 inside the box. The cable runs back to an SMS power card that is plugged into the SMS power connectors that are used for the 1053 console printer, disk drive, 1134 paper tape reader, 1055 paper tape punch and 1627 plotter devices. 

HOOKED UP THE RUN SWITCH AND DISK UNLOCKED LAMP WIRING

When I tested the wires to determine which switch terminals each connected, I discovered that the switch was not working properly. It is a DPDT switch although only the Normally Open and Pole terminals are used. One of the two poles was not connecting to either the NO or the Normally Closed contacts.

I used Deoxit to spray inside the switch and exercise it until I restored a good low resistance connection when it is put in the ON position. The four wires from the switch were inserted into the terminal blocks on the front of the disk drive. A doubled set of wires from the Disk Unlock lamp on the main console was plugged into its spot on a terminal block. 

An end of a wire snapped off the pin connector that was plugged into a terminal block - but I soldered it back together easily. 

SMS POWER CARD SNAPPED OFF - SIGNS OF PRIOR DAMAGE AND BAD REPAIRS

I found that the card was snapped off at the fingers. One of the two finger sections showed signs of a prior break and a repair using some kind of liquid metal squeeze on material. It was also wrapped in black vinyl electrical tape, probably to keep the parts together.

This is the means of delivering 115VAC hot and neutral to the disk drive, as well as a good ground connection to the 1130 frame from the disk drive. I could directly wire this up, but that would not match the way that IBM connected the disk drive. 

DESIGNING NEW SMS POWER CARD TO BE FABRICATED

I fired up KiCad and began to design a compatible SMS power card. Once it is fabricated by JLCPCB I can use one to repair the disk drive connection and keep a few for other possible uses. I think the SSM museum could use one so I will send one to them.