READJUSTING THE REMOVED PARTS
Selection Stop Plate
This is a simple adjustment, just a bit awkward due to the narrow zone where the wrench has to fit to tighten the screws while holding the plate from moving.
Cycle Clutch
As you can see from the multiple diagrams above, the print cycle clutch has quite a few settings that must be checked or adjusted in order to work properly. I methodically moved through them. Most are easy to measure and straightforward to change.
C2 Switch
I hook up a VOM in continuity mode to the switch. The hand cycle tool I used to turn the shaft of the typewriter has degree markings, which gives me a way to measure where the switch contacts are opening and closing.
The adjustment is done by rotating the cam and then moving the bracket around until the make and break points are achieved. First I had to disconnect the switch bracket in order to get to the two setscrews that hold the cam on the shaft.
I then loosened the two tiny setscrews (at 90 degrees from each other) and turned the cam to achieve the proper orientation while the cycle shaft was at rest.
The bracket was replaced onto the frame and moved until the contacts just broke while the print cycle shaft was left at the 20 degrees of operation point. I then verified that the contacts reconnect right around 120 degrees of print cycle movement.
Filter Shaft
On normal office typewriters, those with keys that are pressed by a human, the key latches down and has to be reset at the end of the print cycle to allow the next keystroke to be accepted. The filter shaft has a cross section that is a very thin oval, the two ends are what push the keys back to the restored position.
This rotates as part of the print cycle, which is a 180 degree turn of each shaft, thus the two lobes on the filter shaft. In addition to its (unnecessary) role of restoring keys, this has a cam which pulls a rod to trigger a space of the carrier. A pawl is briefly pulled out of the rack of teeth that hold the carrier in place, so that the coil spring energy pulls the carrier to the right where the pawl falls into the next tooth (column). IBM calls this spacing action escapement.
We want to move the carrier after the typeball has already begun moving back away from the paper and ribbon, not while it is still in contact, otherwise we will get a smear instead of a clean letter. The cam is adjusted so that it pulls the rod after the critical position of the ball is past, yet still releases the pull rod when the print cycle comes to rest.
This was straightforward to check and was set correctly. The filter shaft on this keyboardless typewriter used a circular shaft rather than the oval version from office typewriters.
Carrier Print Shaft
This is a very important adjustment. It rotates the rod that the carrier slides across, thus it turns the mechanisms inside the carrier. A notch runs along the length of the rod into which the various cams in the carrier are keyed.
A print cycle begins when one or more solenoids are engaged by the 1130 to request a particular letter to be printed. These solenoids pull on levers that dangle under a wide plate, so that the lever is either under the plate or out of the way. The plate will be forced downward during a print cycle, thus pulling all levers that are still under the plate.
The print cycle clutch is triggered by the activation of any solenoid. It releases the print mechanism to turn 180 degrees before the clutch latches back to idle. As the shaft turns through the 180 degrees, it is rotating cams that push the selection plate downward.
The downward pull of the levers that were selected cause the mechanisms in the typewriter to change the tension on two thin metal ribbons that are routed to the carrier. One of the ribbons turns the typeball left or right, achieving one of 11 rotation positions. The other ribbon tilts the typeball to one of four rows of characters. Thus the selection picks one of the 44 unique type characters on the ball.
As the print cycle proceeds, the shaft running through the carrier is turning. It begins moving a set of latches which will first lock the ball to the tilt setting and a bit later push a lever up into a tooth on the typeball to lock in the rotation setting.
During our print cycle, we have two sets of motions occurring. The metal ribbons are moving based on the selected levers and downward plate movement. The locks are engaging and releasing for tilt and rotate.
These must be synchronized. If the selection mechanism is still moving a ribbon, not yet at its final rotation or tilt tension, but we lock the ball then we have two bad things happening. We may have selected the wrong character, locking the ball before it gets to the intended target. We are also locking the ball but putting tension on the ribbons, which might cause them to break.
This is why we want the shaft going through the carrier to be in a very precise relationship to the print cycle overall. We want to see the typeball move to its intended position just before the latches lock down the typeball. We also want to see the typeball unlatched before we begin restoring the ribbons to their rest position as the selection plate and levers move back up.
I hand cycle and carefully observe the motion of the ball and of the latches, both at engagement of the latch and at release. The shaft position at idle is adjusted until I am satisfied with the synchronization. This is all checked with extremes of rotation and tilt, the worst case for problems in timing. Thus I selected characters with a +5 and a -5 column and a tilt of +3. All worked properly.
Gear Lash
This is an easy adjustment, which must be done to allow smooth movement of the print clutch shaft, filter shaft and carrier shaft gears as they mesh and turn together. We don't want too much friction nor too sloppy an engagements.
Final Checks
I first checked that the print shaft going through the carrier is in the right orientation, with the groove in the shaft just a bit rearward of straight up, about the 11PM position on a clock dial. I also checked the position of the cams for the spacing and shift mechanism lockout, as they need to be at the proper place when the cycle is idle.
I then check for malselection of various characters, using the hand crank to see when the locking bar enters the teeth on the selectric type ball. I had to do this for both upper and lower case positions, testing -5 and +5 rotate operations. All appeared to be correct.
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| Hand cycle tool to manually operate typewriter |
TEST UNDER POWER
With the console entry switches (CES) removed from the front panel, the typewriter could be moved four to five feet from the 1130 due to the long cable. I plugged the SMS power and signal cards back in with the typewriter on a table next to the 1130, so that I could run it under power to see how everything works.
The front panel buttons Tab, Space and Return were pushed to observe how the carrier moved. Everything else will be tested by commands issued from the IBM 1130. I let the residual code from the disk diagnostic run to print a few messages.
It was obvious that the mechanism to hold the tab microswitch open was not working properly. The tab torque bar snapped right back to idle position while the carrier was still in motion. This was reflected in the typed output which was distorted when new commands were issued during a tab move.
I also noticed something different between this typewriter and the one on my personal 1130 system. The tab torque bar lever that activates the microswitch is able to jam against a metal part that is part of the paper movement system.
Specifically, the platen (roller that the paper curves around) sits on four small roller shafts and has a metal plate that forms a sandwich of platen, paper and this plate. This extends for about a third of a circumference of the platen centered near the bottom. The metal plate sits on two metal parts, one at each end of the typewriter.
You can see in the picture above that the metal part extends out to brush against the end of the torque bar plate as it rotates up. Compare that to the position of the metal part on my typewriter, shown below.
REPLACED TWO OUTPUT BUFFER CHIPS FOR V2315CF MAIN BOX
Due to an error on the 2310 Interface Board PCB, one of the control signals from the Virtual 2315 Cartridge Facility (V2315CF) was exposed to 12V when it was intended as an output to drive a MOSFET transistor. The signal would turn on the Unlock lamp on the 1130 console when the V2315CF did not have a virtual cartridge file loaded and it was operating in virtual mode. In its real mode, the 2310 disk drive inside the IBM 1130 would directly control that lamp.
I received a supply of replacement buffers for both input and output signals from the V2315CF and installed one on each of the two V2315CF boxes I had built. Having hacked the existing 2310 Interface Board PCB to cut traces to the 12V supply and add a bodge wire, it is now safe for use. The new version of the PCB should arrive tonight so that I can create an unhacked version for production use.
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