HP-97 Printer Malfunction

[Paul Berger (Canada)]

The gear the usually breaks is the middle idler gear, the normal failure mode is teeth get stripped off. If you need a replacement I have extras from a batch of aluminum gears another member had made recently.

You mention a faint whine, do you think this is the motor? It will display error if it detects that the print head has not moved.I would suggest that you take off the back and observe the printer when it attempts to print. You can either hold the battery pack in place, or do as I did, fashion a bar to hold it in place, I used coat hanger wire for this purpose, hooking one end under the board (be careful you don't short anything) and put the other end under one of the printers mounting screws. This will hold the battery in place so you may freely observe the printer.

The black wire on the forms feed switch being disconnected should not lead to erratic operation of the printer, it should only cause the forms feed button and end of forms switch to not work, so I would suspect there is something else wrong.