Calculator Canon MP 1210-D

[zoidbergslo]

Hey all

I found this old calculator at home. I am guessing these are rubber domes. Can someone confirm this. Keycaps are very thick doubleshot.

canon1

canon1.JPG (199.92 KiB) Viewed 7200 times

canon2

canon2.JPG (160.44 KiB) Viewed 7200 times

canon3

canon3.JPG (198.35 KiB) Viewed 7200 times

canon4

canon4.JPG (119.87 KiB) Viewed 7200 times

[Peter]

Why don't you take it apart and have a look ?
These old calculators always have awesome keycaps,
made to last the lifetime of any accountant .
I've tried to look into what switches they may use, but all the collectors
seem to not care about that ..
Considering how expensive they where, I
wouldn't be surprised if you can find interesting quality-switches in some of them .

[Parak]

I'm guessing some sort of prototopre.

[Muirium]

Great caps. Reminds me of many an early 80s board.

The stems say rubber dome to me. What does it feel like? Spongy, and it's very likely a regular dome. But perhaps it's something more interesting. The caps are high end.

[mr_a500]

That looks similar to the switches in the TRS-80 Colour Computer 3:

Coco3.jpg

I haven't actually opened the switch, but it doesn't feel like rubber dome. It's actually quite decent (unlike uber-crap CoCo 2 keyboards) - not as good as linear ALPS, not as bad as Mitsumi.

[HaaTa]

Reminds me of this keyboard
Dome unfortunately (STM PPC002)




Sorry, old pics, keyboard wasn't clean

[mr_a500]

Just for the hell of it, I opened my CoCo 3 keyboard. There's no rubber dome - just a spring and a plastic thing that pushes two membranes together:

Coco3_1.jpg

Coco3_2.jpg

You'd think that this kind of thing wouldn't last long before the membrane wore out or something - but I typed on this keyboard a hell of a lot back in the 80's and I see no wear at all. It's also strange that so simple and cheap a switch can feel so much better than rubber dome. (pity this didn't become the standard instead of rubber dome)

[Muirium]

Indeed. Ultimately, rubber dome's all-consuming advantage was simple cheapness. Guess your alternative must have cost a little more. It's not like the companies making domes (besides of course total misfit Topre) cared for durability or feel after the first week or two.

[zoidbergslo]

I asked here first if someone knows that switch type. I'll open it up and take few more photos.

[Daniel Beardsmore]

Interesting — different coloured spring instead of different coloured slider? That's a new one.

Any obvious difference between them?

I realised afterwards that the yellow dome in my BTC 5149 under the space bar might be a stiffer dome, but I've reassembled the keyboard without thinking to compare them.

[Findecanor]

I think I have seen those switches and caps on a Silver Reed typewriter (probably still under a mountain of stuff in my apartment block's recycling bin).

[mr_a500]

Interesting — different coloured spring instead of different coloured slider? That's a new one.

Any obvious difference between them?

The green spring for the space bar looks the same gauge metal and is the same size, but has one less loop. It's slightly more firm.

That keyboard was easy to clean - just remove the membrane and springs and you can throw the whole thing into the sink. (you sure can't do that with a beam spring keyboard... well, you could - but it wouldn't be a pretty sight)

[Daniel Beardsmore]

Stiffer springs are typically longer — how can a shorter spring of the same gauge be firmer?

[mr_a500]

I didn't say it was shorter. It's the same length, but with one less loop.

But actually, now that I can see it magnified, it does appear that the green one is a thicker gauge. (my eyes are going... need eyeball repacement)

springs.jpg

[TacticalCoder]

Funny you post that: sunday at a flea market I found a fully working calculator for 1 Euro. Couldn't resist

It has double-shot keys :

condor1200pd.jpg (259.66 KiB) Viewed 6948 times

[Daniel Beardsmore]

Close-up of the switches? :)

[Daniel Beardsmore]

Necro for great justice — most of the switches on this page match the Mitsumi latching switch in a C64, and the C64's slider design also happens to match that Condor 1200PD:

http://deskthority.net/photos-f62/commo ... t8406.html

The difference is that the keyboards on this page all have the spring under the slider, instead of on the outside above the slider.

It would be nice to see if any of the keyboards in this topic can be confirmed as Mitsumi.

[jacobolus]

Stiffer springs are typically longer — how can a shorter spring of the same gauge be firmer?

The stiffness is determined by the spring diameter, the wire gauge, the length of the “active” part of the spring, and the number of loops. A spring with fewer loops is stiffer than a spring with more loops.

[TacticalCoder]

Necro for great justice

Great necro!

Now I realize I never posted the close-up of the switch on my calculator: will do ASAP

[TacticalCoder]

Here's a close-up of the switch of my calculator which Daniel asked for many months ago

[Daniel Beardsmore]

Thank you. Turns out it's not Mitsumi at all, or even close: it's [wiki]Alps integrated dome[/wiki].