IBM 1130 typewriter (console printer) repair and adjustment - part 2

BELT REPLACEMENT

The belt between the motor and the operational shaft is blocked in by the print cycle clutch on one side and a metal bracket through which the operational shaft passes in a bearing. Thus I have to remove some part of the shafts to make room for the belt to be fitted around the shafts. 

The print side (left side when looking from the front) is easiest to take apart with minimum adjustments needed upon reassembly. I remove an assembly with intermediate gears that connect the main shaft with others such as the print shaft that the carrier slides along. With that removed, I can unhook the end of the main shaft to pull it partway out.

The motor belt turns a pulley that is one end of the operational shaft, the part that rotates continuously as long as the motor is turning. The pulley has the print cycle clutch attached to it. That couples the turning motion to the left shaft when a character is being printed other wise the shaft to the left of the pulley does not turn. 

When I pull the left shaft out of the pulley and print cycle clutch, it opens a gap that I can maneuver the new belt through. There is a little bit of wiggling and twisting involved, but it is easy enough to fit the belt around the pulley with the other end extended back to the rear of the typewriter where the motor sits. 

This plate holds the end of the shaft that extends to the print cycle clutch. I have several parts to remove in order to be able to pull the shaft leftward and open a gap. 

You can see two screws across the bottom that hold the cam operated microswitch (C2 switch) assembly to the typewriter. The black plate holding the end of the shaft has two screws plus a nut to remove. There are plates, nuts and other mechanisms behind most of those fasteners that must be removed as well.

The shaft slide out of the clutch body and gave me the gap.

The belt has to move around the cycle clutch release arm you can see just to the right of the gap. A bit of a twist to the belt and some pushing moves it so the belt can fit over the cogged pulley on the right. Below you can see it over the pulley.

The belt is pulled from the rear of the typewriter and fitted over the small cogged gear on the motor shaft. 

Replacing the shaft involves maneuvering it back to slide into the cycle clutch then replacing the screws and nuts on the plate. The nut has a post on its rear over which a spring loaded pawl sits. That pawl stops the print cycle shaft from bouncing a bit in reverse when a cycle ends, by falling into a notch on a cam to hold the shaft at its rest position. The pawl has a teeny circlip holding it onto the nuts post. 

Both screws thread into the frame, but one of them is longer and its threads extend on the rear to hold the selection stop plate. That is a plate that keeps the pivoting selection bar that twists and tilts the golf ball from going too far down. It is held by nuts on two screws - this one on the rear of the print cycle shaft plate, and one of the two screws holding the C2 switch plate onto the frame. 

The plate takes up a lot of the space available, thus there is very little room for a tool to put the nut on the threads.

At first I tried to use tape to hold the nut in place, backed out the screw on print cycle shaft plate and then engage the threads in the nut. That didn't work well so I switched to forceps to hold the nut while I turned the screw clockwise to catch the threads. 

With that started, I could fit a thin wrench in there to tighten it up. However, I had to get the other screw through the plate and install a second nut. The other screw is the right one of the two that hold the C2 switch plate in place.

Using the same technique - partially installing the screw, holding the nut with forceps and then turning the screw clockwise, I got the nut engaged on this second screw holding the stop plate.

You can see in the picture above that the stop plate keeps the more goldish looking pivoting mechanism from moving past a certain point. I will need to adjust the position of the plate, along with a ton of other adjustments, once I finish the reinstallation of all the parts. 

Once I replace the intermediate gear train, all the shafts are connected again. It is important that the three shafts are synchronized = the left shaft connected to the pulley, the print shaft that the carrier runs over, and the filter shaft that trips the space function at the end of a print cycle. These are several of the items1 to be adjusted, although I worked very hard to get the gears back together as close to in sync as I could initially. 

The print cycle clutch has a number of adjustments that must be made since it was also disassembled. The C2 switch has to be adjusted to open and close the switch contacts at the exact rotary positions during a print cycle - this blocks the 1130 from activating selection solenoids during the time when the type element is turning to position. I anticipate a good hour of fiddling to get all the adjustments required for the parts I had removed completed to my satisfaction. 

I did have one part that fell out during disassembly that I am struggling to identify so that I can reinstall it. 

I looked through every part on the parts manual for the typewriter but didn't see any candidates. The parts manual groups parts in diagrams based on their function, not their locations. Thus when looking at the selection mechanism diagram that has the stop plate I installed, you don't see the C2 switch assembly because that is on a different diagram. 

Finding parts that fit together in one location is not easy, since they can be spread across dozens of diagrams. However, I know it had to have dropped off when I was removing some screw or nut involved in the belt replacement. 

Looking at the thin material this is constructed of, we can see it isn't directly moving or handling force. We can see an elongated hole meaning that its final position is adjusted. There is a notch and a step on the end that must engage a rod or spring. These are all clues.

I have opened up the typewriter on my personal 1130 system and will be peering closely into every part of it hoping to