Post Reply 
HP-41C: The "1" key fails sometimes (weak contact).
09-13-2021, 11:31 AM
Post: #4
RE: HP-41C: The "1" key fails sometimes (weak contact).
Hi There,

Its a pretty straight forward job on the surface. 4 screws are under the feet, remove the rear cover and you will see the processor board and the main keyboard/display pcb. You will see tiny holes in the main pcb which are located behind the keys. The method (IIRC by a guru from here Randy) was to put a drop of DeOxit over/in the hole and use a single strand of wire (stiff like from a wire brush) to go in the hole and gently rub the interior contact surface. I like to repeat it a few times while working the button.

Only issue you may run into is how the processor board is attached. The older Cs will have nuts holding them to the lower posts, newer ones should just lift off. You might have to remove that board to see the hole for the "one" key.

When done, reassemble and test.

You might find stuff you need to fix as you go but hopefully not. They are not that fragile IMO as long as you don't force things.

Take Care!
Find all posts by this user
Quote this message in a reply
Post Reply 

Messages In This Thread
RE: HP-41C: The "1" key fails sometimes (weak contact). - BillBee - 09-13-2021 11:31 AM

User(s) browsing this thread: 1 Guest(s)