BUMPER STOPS UPWARD CARD MOVEMENT AS IT IS EJECTED INTO STACKER
As cards are fed through the read station, they continue to the left and curve upwards to be ejected out into the stacker. The card strikes an elastic bumper that arrests its movement and allows it to fall downward gently.
The card pusher oscillates left and right at the bottom to gently move the card leftward until it is against the stack of cards previously ejected. The stairstep shape of the card pusher initially places the ejected card higher than the top edge of the stack, but then nudges it down the steps while the card slides down to end up well aligned against the other cards in the stack.
WARNED TO CHECK THE CONDITION OF THE BUMPER
The bumper is another of the materials IBM used in the 1960s that degrades with the passage of time. Foam insulation, rubber and plastic parts outgas the chemicals that provide the elasticity and other characterists, so that by now they are brittle, crumble or in some cases have turned to a sludge.
It sits in the area marked A in the diagram below at the top of the stacker assembly. The card flying up from below will bounce to a stop off the bumper, then drop to where the card pusher can move it against the other cards.
The bumper itself consists of a holder (61), a soft elastic material (60) and a tougher outer face (62).
EXPERTS WHO RESTORED A 2501 IN EUROPE ALERTED ME TO CHECK THIS
Friends who have restored 1130 systems for a museum had previously restored the 2501 Card Reader as part of that effort. They encountered the broken plastic gears during that work and were the source of the design files I used to fabricate my replacement parts.
The found that the bumper on their reader was cutting or damaging cards because of its degraded state, so they replaced it. Because of this, they warned me to check the bumper on my 2501. The bumper was sitting there seemingly good but when I touched it to check the elasticity, it broke apart.
Fortunately, the team had produced a design file for the bumper holder onto which they glued some firm foam. I was given the file and will build the holder. I already have suitable firm foam to add to it.
There was a way to rig a card in the stacker so cards coming out of the reader would be miss the bumper and go flying out of the machine. We would rig it, then give an "important" deck to a new operator and watch them run around figuring out how to stop the reader when the cards started flying everywhere.
ReplyDeleteYes, just tape a card over the bumper and the two dangling stop levers, so that the card coming up into the stacker will slide out over the lip and fly into the room.
DeleteThat’s so evil and now I must try that 😄. This happens too when the stacker mechanism is not turning and you process a large deck. At some time the cards come shooting out and you have to search them all around the machine …
ReplyDelete