The Museum of HP Calculators

HP Forum Archive 19

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Opening HP41C
Message #1 Posted by Alberto Fenini on 7 Jan 2010, 4:17 p.m.

Hi all, I'd like to clean and repair my newly arrived HP41C, particulary the Enter key, that is firm on the left side, but is weak on the right side of the button. I tried to open the unit, but it looked to me the keyboard unit is much like the woodstock one, soldered and tied together. Is there any way of disassembly the keyboard and get access to the underneath surface ? Thank you very much for help, Alberto

      
Re: Opening HP41C
Message #2 Posted by Vieira, Luiz C. (Brazil) on 7 Jan 2010, 5:29 p.m.,
in response to message #1 by Alberto Fenini

Ciao, Alberto;

as you mentioned, the keyboard is locked in place by melting plastic posts. The only way I know is to cut the borders of each one. I am trying small screws, like the ones used in glasses, to fix the keyboard in place after removing. Will talk about this later and add some pics, now I have to leave...

Cheers.

Luiz (Brazil)

            
Re: Opening HP41C
Message #3 Posted by John Robinson on 8 Jan 2010, 3:12 a.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

I have successfully disassembled the 41 keyboard by "popping" off the top of the heatstakes with a small screw driver. The plastic that comes off is kinda donut shaped. By doing this instead of shearing off the whole top of the heatstake with a knife, the centre of the heatstake remains. To reassemble, I use "hot" glue, while maintaining pressure on the keyboard from behind.

I actually squish down the glue with my finger (after licking it first) to set the glue quicker and force a little more around the heatstake.

I have done this on five or six 41 calcs now and it works a treat !!

Cheers, John


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