An early model
"QWERTY" keyboard layout showing the lack of a '1' key on the left end of the upper number row of keys.
Between the times of the introduction of the 'shift' action and the electric ball type printer head, the actual printing keys were forced on to the long lever arm. This was a flattened metal cap pressed onto the arm. Very often lever arms got crossed up and in doing so, caused one of the effected key heads to be punched off the lever arm. Depending on your machine, access to the internal parts might be user allowed and in many cases were only technician accessible. So recovery of the type key was no a sure thing.
Yes some models required the
l for a
1 all the time but since the I was (and still is) a popular key to use, it was often involved in substitute schemes also. Even when the ball printers came out, the letters were soldered onto the balls and the frequently used letters often fell off. Almost every office I went to kept a replacement ball around for such failures. This afforded quick remedies but still needed the typist to know the shortcuts so a document could be finished before the repair was made.
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