hp41c key 1 not very clicky

[GeorgeOfTheJungle]

Hi,

I have taken apart my 41c (1943A) because the key "1" doesn't click properly and I have discovered that without the cpu board it clicks properly again so it has to do with a deformation of the structure/keyboard pcb that happens when the cpu board is put in place.

Is this a common problem?
How can I fix that?
Any ideas please?

This is my first time here @hpmuseum, so I'll take this opportunity to say hello to everyone!

Hello!

[Ángel Martin]

Hello George - let's hope your screw posts withstand the experience... they\re known to be the weakest link in the chain for the 41 assy.

Good luck!

[GeorgeOfTheJungle]

(05-24-2014 11:30 AM)Ángel Martin Wrote:  Hello George - let's hope your screw posts withstand the experience... they\re known to be the weakest link in the chain for the 41 assy.

Why did they put two different nuts? the golden one seems to be smaller than the silvered!

[GeorgeOfTheJungle]

The keys 1 and 2 working but not clicking: it seems to be a common problem... but how to fix that?

Anyone?

Please?

[Gerson W. Barbosa]

(05-26-2014 04:51 PM)GeorgeOfTheJungle Wrote:  The keys 1 and 2 working but not clicking: it seems to be a common problem... but how to fix that?

Anyone?

Please?

Key '3' here (HP-41C, 2121B58157)

[Ángel Martin]

Afraid it's related to the internal key design - of which I don't know enough but have heard repeated times the domes can collapse and when that happens it's the end of the key - at least of the clicking part.

I 'sppose a really handy person could exchange a single key but the keyboard assy. may share a common domes layer, in which case we're back to square one? Probably the best approach would be to cannibalize one from a defunct unit on eBay...

Just saying, not sure if that's accurate. Better ask some of the hardware gurus, like Tony Duell or Geoff Q.

[Johnboy]

I have disassembled and reassembled at least four 41c keyboards, and replaced keys that are not clicky anymore. It's not an easy job, but it is possible.

You will need a donor calculator to supply a replacement metal clicky disc. I use a hot glue gun to reassemble the keyboard.

Let me know if you want guidance.

Cheers,
John

[GeorgeOfTheJungle]

(05-27-2014 06:57 AM)Johnboy Wrote:  I have disassembled and reassembled at least four 41c keyboards, and replaced keys that are not clicky anymore. It's not an easy job, but it is possible.

You will need a donor calculator to supply a replacement metal clicky disc. I use a hot glue gun to reassemble the keyboard.

Let me know if you want guidance.

Yes indeed, I need guidance.

The part where one cuts the plastic rivets, plus the hot glue to hold it back together part of it really really makes me feel nervous.

Is that a good fix? Or will I botch my 41c forever...?

Cheers

[GeorgeOfTheJungle]

(05-27-2014 06:57 AM)Johnboy Wrote:  Let me know if you want guidance.

Johnboy? Hi?