Disk cleaning, mode switch plate, and paddle card repair

 CONVERTED RUST PRIOR TO PAINTING MODE SWITCH COVER

As you can see, it took multiple treatments to get down through the layers before it was safely encapsulated and ready for painting.

NEUTRALIZED RUST ON PARTS OF THE DISK DRIVE

As you can see, the rust went pretty deep in this section which means I have to go over it again and again, scraping away rust layers and converting, until it is sealed up.

PADDLE CARD REPAIR

The power paddle card for the 1053 printer of the System Source Museum 1130 had cracked. It appeared broken when I removed it from the 1130 at the VCF East event on the final day, but it may have broken during the removal. In any case, it had to be repaired.

I first epoxied the phenolic card itself to mechanically repair it. It had cracked the traces for a few power lines, but not the ground nor the main 115VAC pads going to the Selectric motor. The impacted wires were +12V, +48V and the frame ground. These I bridged with wire across the two halves of the break. Fortunately the break was not down on the fingers that insert into the SMS socket, thus the added wire does not block the card from inserting neatly into the machine. 

I brought the 1053 back to Florida because the rotate tape had broken on the machine, in large part because the spur of the moment demo I created for the show typed a # for every 32768 rounds of multiplication. I intended it to give a sense of the speed of the machine in doing additions and multiplications, but the # character is the position of maximum rotation tension. 

That character is on the side of the ball requiring the lever to add 180 degrees of pull, plus it is a rotation of five columns. I couldn't have chosen a more punishing character for the rotate tape to be stressed. It still shouldn't have broken, but the existing tape did have some bends in it which I believed would be okay; in hindsight, the flexing of the tape at those bends caused it to give way.

A new rotate tape will arrive today and I will install it on the machine. I will then ensure the adjustments are just right with particular emphasis on the worst case characters. It will be picked up on the next trip down here by SSM.