Dear typewriter enthusiasts,

found an IBM 6787 at the bulky waste including a disc drive, a couple of ribbon cartridges and type wheels, all very fascinating and in good shape.

However, after writing a couple of lines an error 215 occurs which makes the machine freeze until powering it up again. The manual says is was a type wheel problem. Rather than repairing it to death right in the beginning I tried a little further and found out:

If the left margin is set a couple of spaces to the right, I can write a while without getting the error. But upon each carriage returns, the left margin would move a little more to the left until it gets to the physical limit. Then, after another 1-2 lines of text error 215 gets back.

Obviously it can not keep its left margin which is the cause of the somewhat misleading error message.

My problem is that I don't understand where the slack comes from. The carriage is controlled by a step motor which should produce precise movements. The connection between the motor and the cartridge is by a tooth belt. Skipping teeth is hardly possible.

Does anyone have a solution? The mechanics was not only used by the 6787 but also by 6746/6747 and probably others.

Also: Is there any source for spare parts other than the ribbon cartridge?

Cheers,

   Thomas