IBM 1130 typewriter (console printer) repair and adjustment - part 1

REMOVAL OF TYPEWRITER FROM 1130

The belt snapped so that the motor spun without turning any of the typewriter mechanisms. I had to remove the machine to replace the belt and perform some other fixes that were needed.

To remove the typewriter, signal and power cables must be disconnected from the SMS connector block down inside the 1130 and snaked out of the machine. 

The front panel of the typewriter holds the Console Entry Switches (CES), sixteen toggle switches that are read by programs to select options and used by the hardware to load certain registers. They limit how far the typewriter can be moved from the 1130 since the ribbon cable to the CES is not very long. 

I realized that I could unscrew the mounting block for the CES and have that flopping around near the 1130 while the front panel can be put back on the typewriter to support adjustment of the pushbuttons for tab, return and space. 

RESOLVING THE FAILURE OF SOLENOID DRIVEN SPACE FUNCTION

Using the hand crank, I tripped the space solenoid. The clutch on the operational shaft that handles space, backspace and tab should spin 180 degrees then stop - I verified that it did. The rotation of that clutch should pull down a bar at the rear of the typewriter and pull a linkage that is placed under the lip of the bar by the space function trip mechanism. 

That linkage is coupled through some parts to pull down on a lever that pulls the space torque bar before the claw pops off the torque bar end. The space after typing characters works, so the torque bar itself and related adjustments are good, however this is activated by a separate mechanism using a pull-rod from a cam which rotates in a print cycle. Thus space is done by two separate means, but the adjustments interact a bit. 

It didn't take long to get both working properly. The final test will be driven by the 1130 under power, but for now all looks good with spaces. 

ADJUSTING FRONT PANEL BUTTONS TO OPERATE SPACE, TAB AND RETURN

The buttons did not push far enough to trip the levers that push down on the function levers. These spring loaded levers are held forward but when pushed down they pull backwards to trip the operational clutch and to move the related function linkage under a bar that will swing down with clutch rotation. 

The first issue was loose screws holding the cable sheaths in place so the cable inside will pull down on the mechanism. In the picture above you can see the screws across the top. 

Next I had to adjust the levers that are behind the pushbuttons on the front panel, so that they pulled enough on the cable to trip the operational clutch latch. 

LUBRICATION WORKOVER TO IMPROVE PARTS MOVEMENT

I went over many points in the machine to flush out any stale oil and ensure the machine parts move freely. The operational shaft which moves continually under motor power was the first area of concern. I then lubricated all the parts that move with the operational clutch when a function is selected. 

Next up was the print cycle mechanism in the frame of the typewriter. I made sure all gears and bearings moved freely, as did the print cycle clutch and the shaft to its left. The space cam and shift lockout cam parts were also given attention as they move during the print cycle. The main print shaft that runs through the carrier and its bearings were checked for easy movement.

Up on the carrier, I lubricated all the parts that swing, rotate or slide to select a position on the typeball and to throw the typeball at the ribbon and paper. This took a while but I had to assure easy movement to lessen the load on the motor and belt. 

I then paid attention to all the linkages in the rear that implement space, backspace, tab, line feed and carrier return activation. These seemed a bit sticky since the tab and return operations weren't consistent when the diagnostic was printing status.

Next up were some torque bars and other linkages for the space and tab operations. The last step was to move around the machine looking for any other moving parts that weren't operating freely. By the end of all this work, I was satisfied with the lightness of the resistance for everything except carrier return. There is still quite a bit of force needed to drive the carrier back to the left. I will investigate more later. 

MISCELLANEOUS OOPS

I was working on the fit of the 2501 card reader hopper gear, a plastic ring I had printed to fit over an aluminum disk, replacing the IBM original plastic ring which disintegrated with age. The gear was designed with a recess for the disk to fit into, but the edge of the gear teeth on the side with the recess had bowed inward a bit. This made the fit of the disk quite challenging. 

As I was trying to get it to fit, I applied a bit of bending pressure against the bowing, but I ended up breaking the ring in half. I think I need to select a different material for this part when I have it made again.