Saturday, October 11, 2014

1053 console printer restoration work, plus more coding on keypunch interface


The cause of the perpetual print cycles was a small spring for the restoring lever, underneath the machine, which had come loose when I connected the cycle latch lever spring a few days ago. After putting it back in place, the machine does not attempt print cycles when not requested.

Hand cycle wheel in place - apologies for the blurry focus

Spring hook tool used to affix small springs
I used the Hooverometer, an IBM tool for making certain settings on these typewriters, to get the cycle clutch latch lever set properly, since I had removed it to move my new motor belt into place. Setting up the tool to marker 3, it is placed on the latch pivot pin and the hook should just touch a shaft above. Moving the cycle clutch latch until these lined up properly and tightening down the screws was all that had to be done.

Hooverometer in approximate position for cycle latch adjustment

Hooverometer tool for adjusting Selectric typewriters
Index (line feed) operations keep occurring because the interposer (part of the actuating linkage) isn't returning to its full forward position after an index cycle is taken. A restore bail should be accomplishing this. So far, I have looked to verify that no springs are missing and moved the various parts of the linkage to ensure they are not gummed up.

In spite of this, it is still not restoring and thus taking perpetual index cycles. I will need to investigate this further, after I spend quite a while poring over the theory of operations, adjustments and illustrated parts manuals.

I adjusted the red ribbon shift tape tension to get the new replacement tape I installed working correctly. Nothing in any of the manuals advises on tape tension or setup. You loop the tape around and then have to guess how much to move the right hand tape pulley in order to have black or red print depending on the selection.

Right pulley with plastic ribbon color shift tape, adjustment screw at right

Armature to pull or release the ribbon color shift tape 
I tightened the tape while watching the ribbon lift cam follower latch plate shift to the front, however the tape snapped off the metal clip on the right end. Sigh. I was able to improvise a way to hook the clip back on, loosened the pulley greatly, and reinstalled the tape. I will err on the side of looseness, which might mean that it never shifts to the red color, but that can be gradually adjusted when the machine is working until I get the proper color reliably.

Tape snapped off the metal clip

Clip pushed through doubled section of tape, makeshift repair
It appears I have the ribbon color shift adjusted correctly with appropriate tension on the plastic tape, subject only to a full power confirmation once I am ready to be printing output with the 1053.

Cam follower latch in its leftward (black color) position
Cam follower latch in its rightward (red ribbon color) position
I will read more tonight on the index actuating and restore mechanisms until I can spot what is not working properly, causing repeated index cycles. The likely suspect is solidified lubrication but it must be at some attachment or pivot point I haven't yet found. The area where these linkages sit is very crowded with other linkages and parts, limiting visibility.

The two solenoids that activate the carrier return and index functions have microswitches that detect the state of the operation, with long leafs on the switches that extend out and can be touched by metal bars on the actuator arms (they are called contact bails).

Carrier Return microswitch with leaf below bail
Index microswitch with leaf above its contact bail
However, the left and right switches are in very different configurations - one sits above the contact bail, the other is below the bail. Once must be in the wrong position. Nothing in the three manuals clarifies which way these should be configured, nor are the diagrams of pictures of the assembly. I need to do more research on this before fixing whichever is wrong.


I retrieved all my design notes from the workspace and began to properly assign all the signals to the Arduino pins. From there, I resumed writing the startup code to initialize the interface. The punch and the reader cables each have a pair of wires connected together, allowing the Arduino to do a quick verification that the respective cable is attached. If the reader cable is not installed, the unit will still work as a punch but cannot read cards or verify during punching.

The USB serial port is used for diagnostic messages - both normal status and errors - in addition to the text responses on Serial port 1 - the user interface - to every command issued on that port.

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