ATTACHED SPRING ONTO BACKSPACE OPERATIONAL LATCH
The linkage to the backspace operational latch had to be put into place and the spring reattached that will keep it deactivated until the backspace function is triggered. This involved tedious manipulation with spring hooks through narrow openings.
As is my luck, the spring got away from me and hid inside the machinery. After 45 minutes of hunting from every angle I finally discovered where it had wedged and retrieved it. I then went back to the spring hooks and fought it until it surrendered. The spring is attached and working properly.
Finally, there are adjustments that must be made again, such as the trigger condition for a backspace which is a screw with locknut that sits so high on the bracket that during removal, I had to lower it to clear obstacles. This has to be set up right in order for the machine to move just one column backwards reliably. I will address these adjustments a bit later.
REINSTALLING THE TAB AND RETURN CORDS
This is the same process I have done many times already, the only tricky part now is at the end after I have the mainspring pre-wound and the cords attached properly, I have to loosen the return drum, rotate it to tighten up the cords and tighten down the screws to achieve the proper cord tension.
The core tension arm is a pulley that is forced outwards with strong spring force. When the cords are properly tightened, they pull the pulley inwards partway so that the cord tension offsets the spring tension. There are scribed lines on the bracket where the pulley moves and the cords must be adjusted so that the far end of the arm is right at the scribed lines.
This involves holding the rest of the mechanisms steady while turning the return drum to pull on or loosen its cord. Turning it against the spring tension of the cord tension arm is infeasible, so I use a clamp to hold the tension arm all the way in, relieving its pressure. I then adjust the return drum so that the cord holds the pulley at the scribed lines, minus a bit that I estimate, then lock down the drum by tightening the two screws on its hub. The clamp is removed and we assess the tension arm against the scribe lines.
This is a bit iterative but the desired result is achieved when I can space, tab and return with the cord tension arm remaining at the scribe lines.
When I thought I had it all set and removed the clamp, I saw the escapement/tab drum hop forwards, skipping teeth on the operational shaft gears. I then realized that when I move the return drum and tighten it down, I also have to move it back against the bearing in front of the mainspring, otherwise there will be slop that allows the gears of the tab drum to disengage.
At this point the cords are all properly attached but the tension is again inadequate and the return drum is not snug against the bearings. When I get back to the shop I will resolve all that and should have a properly tensioned set of cords. The mainspring must be wound to the right tension once I have the cord properly installed, then we should be done with this extended task.
At this time of year, I have other obligations that reduce my time in the shop to only 3 or 4 hours per day at best, which contributes to the plodding pace of the 1053 repairs.
RIBBON COLOR SHIFT MECHANISM AND MISSING TAPE
The IBM 1130 console printer makes use of bicolor cloth ribbons, which are inked with red and black ink on the upper and lower halves of the fabric. By controlling the height that the ribbon lifts during a character print, the 1053 can print in either red or black. The color is controlled by program commands, firing one of two solenoids to shift to red or shift to black.
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| mechanism inside carrier |
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| lever which changes tension of the tape |
The implementation of the ribbon color makes use of a flat nylon tape that runs across a series of pulleys, much like the metal tape for tilt and rotate runs around pulleys. One end of the tape is hooked to the right of the carrier, the tape runs to the right edge, around a pulley, back in front of the carrier to the left edge, then down to the solenoid lever at the bottom left. The tape then goes back up to another pulley on the left side and runs to the left side of the carrier. On the carrier is a small pulley to route the tape back to hook to a pull mechanism that controls the ribbon lift.
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| pulley on carrier |
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| ribbon lift lever circled |
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| tension adjustment |
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| right pulley |
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| solenoid lever |
The original nylon tape was missing and there is no source of replacement ribbon. The IBM original had appropriate metal hooks on the ends to attach to the carrier. An adjustment screw moves one of the pulleys in and out to fine tune the tension so that it reliably moves between black and red halves of the ribbon.
TESTED LACING CORD AS A SUBSTITUTE
I temporarily tied some lacing cord onto the carrier and ran it through all the pulleys to test its fit. It does appear to stay on the pulleys and work appropriately. The carrier moves left and right without impacting the tension on the cord, while the solenoids tip the lever up and down to add tension which is transmitted into the carrier's ribbon lift lever.
MUST FASHION GOOD HOOKS ON EACH END AND DO A FINAL ADJUSTMENT
I believe a small ring, a miniature version of the rings for key chains, will fit through the hole in the ribbon lift lever. I need to find or make one. The other end just has to sit over a post on the carrier, it is less critical. When I have workable hooks I will get them fastened securely to the lacing cord and put them onto the 1053. The final step will be to adjust the position of the right pulley to assure that we select red or black as intended.
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