Verification of 1053 Console Printer - part 6 (done with typewriter repair)

THE CLOSER I LOOKED AT THE SHIFT MECHANISM, THE MORE ISSUES I FOUND

This may be no surprise to long time readers of this blog, but the shift mechanism had quite a few adjustments totally wrong and even one unnecessary part installed. As I worked on the brake shoe adjustment to moderate the speed as the clutch moves the typeball from upper to lower case, I began spotting issues. 

When shifting to upper case, the roller does not enter the detent position. The brake shoe was not correct. The shift magnet settings were very finicky. The feedback contacts didn't break and make at the correct positions. This is just a sampling of the maladjustments. 

I can't imagine any way a machine can get this far out of condition normally. It also could not be damage because there is no sign of dents or bending anywhere inside. Either this had been serviced by an IBM customer engineer who was terrible at his/her job, or someone partially disassembled the entire typewriter after the machine was decommissioned. 

The shift clutch has a snap ring on the end of the running operational shaft but this particular machine had two snap rings, one in front of the other, which is definitely not correct. I triple checked every part against the parts catalog diagrams just to be sure there was nothing missing or put in wrong. 

Parts diagram for inner part of shift mechanism

REBUILDING AND ADJUSTING THE SHIFT MECHANISM

I basically disassembled the entire shift mechanism, cleaned it and assembled it while making every adjustment as I went along. The IBM adjustment manual didn't even cover some of the adjustments I had to change. 

During disassembly

Two snap rings instead of one

This ring determines the stop point for upper case shift

Coil spring end fits in hole inside the housing

Cam activates contact switch for feedback on shift status

Spring riding on cam

With all the tweaks, the shift mechanism now stops with the roller in the detent position for both upper and lower case orientations. The contact switch breaks and remakes at the correct points during the rotation of the shift cycle. The shift magnets trip the mechanism and it flips to the requested state every time it is requested. 

Since the shift arm does affect rotation during print character selection, I printed a character at all eleven rotation positions with some hand entered code in the computer. I was pleased that I did not have to go back and readjust the rotation mechanism or the print cycle. 

TYPEWRITER RESTORATION IS DONE!!!

The time I invested was definitely worth it - the shift is performing right to spec now. This was the last problem area on the typewriter. It is now sitting on the machine where it belongs. Now that there are no known issues on the machine, I can move on to do final checkout of the system, running the various IBM diagnostics.