HP-97 with different problems


I'm trying to repair a friends HP-97 and need some help.
It sympthoms are:

1. Flashing display, specially the left most digits. The right most are still and not flashing.
2. Printer does not return carrige after being in the right most position. I suspect the reed switch or the magnet to switch the reed to be defective.
3. Only a few of the 'function'-keys work, eg. [sin] and [cos].

I have cleaned the pins cnnecting the PCBs and this helped preventing the calculator craching all the time. But I would like to be able to solve the above problems.

Thank you in advance!
Johnny Bjoern Rasmussen


The easy stuff: 1) Stripped printer gear. 2) A key stuck down. 3) Printer daughter board not seated.

#1 will usually result in a blank display.

Do you have the service manual? It's on the MoHPC collection.


Do you have a good nicad battery in it? If you don't it can run off the AC supply, but the printer won't work nor will the card reader and the left digits may indeed flash.


Katie has nailed it. You need a good battery pack installed.

Plus the printer gear may be stripped causing the printer to not work. Any attempt to use a printer with a stripped gear will result in a locked up machine and you can hear the printer motor quietly running continuously. If the print head is not in the home position, the machine may not even appear to power on.

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