hp11c programable calculator

[Frank]

Is it possible to repair an hp11c. I had two very fine and small springs that came out as I was trying to clean a dust speck from the display window ( on the inside ). This thing worked fine before and passed all tests and is without scratches. Since the springs came out,
the display is not compete when it shows numbers. Does any one have some usefull tips. Or is anyone specialized in repairing the hp11c.
Thanks,
Frank

Edited: 12 Feb 2006, 9:22 a.m.

[Joe Edwards]

Quote:

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Is it possible to repair an hp11c. I had two very fine and small springs that came out as I was trying to clean a dust speck from the display window ( on the inside ). This thing worked fine before and passed all tests and is without scratches. Since the springs came out,
the display is not compete when it shows numbers. Does any one have some usefull tips. Or is anyone specialized in repairing the hp11c.
Thanks,
Frank

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You can contact the person that runs www.fixthatcalc.com. I believe his name is Randy.

Joe

[Randy]

The springs have *nothing* to do with your display problem as they are there to connect the front aluminum bezel and rear ledgend plate together to protect the device from electrostatic discharge.

You most likely disturbed the LCD connections to the logic board by bending or otherwise moving the the elastomeric strips or the LCD itself.

Which version of 11C to you have - the early unit with the removable logic module and LCD or is everything mounted to a single PC board which is heat staked in place?

[Karl Schneider]

Hi, Randy --

You posted,

Quote:

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The springs have *nothing* to do with your display problem as they are there to connect the front aluminum bezel and rear ledgend plate together to protect the device from electrostatic discharge.

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I have a 1985 HP-11C that has a rectangular piece of the legend-bearing back plate missing, on the right side, between both rubber feet. This part of the plate covers one of those "spring holes", so one of those spring connectors is missing.

Does that spring provide anything more than redundancy -- i.e., a second, parallel connection between the "front metal" and the "back metal"?

Thanks,

-- KS

[Randy]

They are not redundant, the spring nearest the battery connects the brushed finish bezel to the back, the spring nearest the ON button connects the keyboard surround plate to the back.

FWIW, Over the years I've seen at least a dozen beat to death Voyagers with no rear plate and no springs... not a one a with problem other than lots of internal keyboard dirt or broken LCD's. All the chips I've ever replaced were in units with intact plates and springs. Your mileage may of course vary :)