Thursday, January 1, 2015

Keypunch mechanical issues addressed

New Year's Eve and kept pretty busy prepping the house for a party my daughter and son-in-law will hold for local gamers tonight. However, I was able to put in a couple of hours tuning up the keypunch. New Year's day, once all the overnight guests woke and left.  I was able to get back into the workarea and the 1130 for a while.


I worked on the keypunch mechanism today, hoping to resolve several problems it has been evidencing. The first problem it had was inability to feed cards cleanly from the input hopper to the punch station. The second problem was failure to register at the read station when a card came out of the punch station. The third problem was failure to eject the card fully from the read station and move it up into the stacker. Finally, the read station card was not moving in sync with the columns of the card in the punch station.

I cleaned and adjusted the hopper feed mechanism. Several rubber rollers needed a bit of deglazing, to achieve approximately the same traction on both the left and right of the card. The original fault was skewing of the card as it was pushed down into the punch station.

Both registering at the read station and ejection to the stacker station are supported by metal rollers on arms that push down on the card to hold it against a rubber feed roller. The arms were not pushing down far/hard enough to cause the card to be moved across. I did some rough adjusting of the arm position and it fixed the eject issue easily.

However, the correct position appears to be very touchy, as each time I tried to adjust it, I either had the card registering well but unable to move through the read station on a release/clear, or it moved through the station but wouldn't reliably register. I will keep adjusting it until I get both registration and movement through the read station to work.

There is an official way to adjust this, which requires that the mechanism be partly rotated through a cycle until a cam reaches its high point, then a feeler gauge is used to measure the clearance to the roller. I don't (yet) know how to manually release and rotate the mechanism, thus I can't get the cam to the proper point to use the official adjustment method.

I believe the lack of synchronization between read and punch station columns is also caused by the same maladjustment of the arms, since the card has to stop in the proper place when registering, which depends on the pressure on that roller that is controlled by the cam. However, once the read station registration is working, I can check the card sync again to see if I have an independent problem.

I asked a fellow member of the 1401 restoration team at CHM about how to make the setting, as well as ways to follow the official adjustment process. Stan told me that he had to make the very same adjustment within the last few weeks on one of the keypunches at the museum. They did not use the official method, but did describe what worked for them.

It appears that I might have a wheel that is too small to work properly - the rubber wheel that the roller contacts, but if I can find a setting in between blocked release and failed registration, I can make do with this. If not, then there are a few spare wheels at the museum but a fair amount of disassembly is required to make the change, so I will avoid the change if it isn't necessary.

Based on the failure symptoms of the keypunch at CHM, fixing my adjustment problem will fix all the outstanding problems of my keypunch. I didn't quite get it sorted out today but I know this will be resolved soon.

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