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Repairing Kaypro 2000+ Keyboard; Cherry Key Switch Questions

Fezzler

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I am restoring a Kaypro 2000+. (Anyone have OS software disk?)

Anyway, about 12 of the keys do not work. The are Cherry key switches. They are black. They have a spring, copper contacts and a diode. Only other markings are an "A" on the lower left of the switch housing top; a "80" on the bottom of the housing; and a "3" on the plunger that the cap attaches to.

I thik they are Cherry MX series. MX3500 or MX1A-11DW. Not sure. They have three plastic post on bottom to sit in pcb card. I think they only have three soldering post, but maybe 4, I can't tell if there is a soldering post on the upper left.

First, the switched look fine. Unless the diode is bad, hard to tell what an go wrong with these as they are pretty simple device. Having said that, I know I have had key switches on my Tandy Model 102/100 that looked fine but worked after replacement. I looked at the pcb board and can't see anything that indicates broader issues. Again, not sure how to test.

So, I'm going to try and relace the switches to see if that is the issue. What is the difference between Cherry MX brown, blue, black etc. Does color matter?

Any advice?
 

Fezzler

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Have you verified the (non) operation of the switches in question with a simple ohmmeter check?

No. I don't know how. But I have a good digital ohnmeter. Where do I measure, across the solder points on the bottom?

I'd like to verify the switches are bad/good. Tell me how and I'll do it and report back.

Thanks.
 

Chuck(G)

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Yup, if you have an audible continuity setting on your meter, use it--it'll keep you from having to look up at the meter. Just the pads across the switch bottom. Press the key, you should get a beep. Start with a known-good key as a check.
 

Fezzler

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Yup, if you have an audible continuity setting on your meter, use it--it'll keep you from having to look up at the meter. Just the pads across the switch bottom. Press the key, you should get a beep. Start with a known-good key as a check.

Okay. Looking at the pins from the bottom, using the two at the top of the keys, they all "beeped" with the continuity test.

The "1" key needs to be press somewhat hard and the 'U" key seems intermittent at first then "beeps." The were all keys I thought no good.

Now what? Look bad traces?
 

Fezzler

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No. I don't know how. But I have a good digital ohnmeter. Where do I measure, across the solder points on the bottom?

I'd like to verify the switches are bad/good. Tell me how and I'll do it and report back.

Thanks.



UPDATE: Some of the soldering points looked old and maybe not having the best connections to the eyelets to the pcb board. So I cleaned and repaired them.
That seemed to do it. I don't know which one was the troublesome connection. LOL. But, sometimes it is better to be lucky than good.

Thanks. So now I need boot disk for Kaypro 2000+ (I think it may be same as the Kaypro 2000). And the hing on the lid is a bit tight, need to fix that. Looking for Kaypro 2000+ MS-DOS 3.2 and boot disk. I assume that would have GWBASIC (were there versions of GWBASIC?) and Kaypro WordStar Professional Release 4.

After that, I'll clean and package and sell.
 

Chuck(G)

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You did good. Touching up the soldering would have been my next suggestion--those keyboards get quite a bit of mechanical stress during use, so it's not unusual that some of the connections go wonky.
 

Fezzler

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You did good. Touching up the soldering would have been my next suggestion--those keyboards get quite a bit of mechanical stress during use, so it's not unusual that some of the connections go wonky.

Thanks for your help. You saved me cost of obtaining new Cherry MX key switch, replacing a half dozen or more to think I fix bad switches when indeed the solder around a few eyelets was not the best. The Kaypro 2000+ is hummimg and I'm remembering what it was like to operate with a floppy drive or two.

You know, WordStar is still a great program. I fear the pioneers of this industry will be forgotten. I hope not.

Fez
 

Chuck(G)

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Thanks for your help. You saved me cost of obtaining new Cherry MX key switch, replacing a half dozen or more to think I fix bad switches when indeed the solder around a few eyelets was not the best. The Kaypro 2000+ is hummimg and I'm remembering what it was like to operate with a floppy drive or two.

WordStar lives on after a fashion in the Joe editor, which is patterned after WordStar's non-document mode. Pretty much the same keys. There's a version for DOS, Windows and *nix OS-es. The later ones use color and can parse various programming languages. But yeah, I started with Wordstar 0.91 under CP/M in the bad old days. I pretty much stopped with WS 4 for CP/M and DOS. I picked up Wordstar for Windows, but didn't care much for it. For business work, I used WS2000 for several years (very different from standard WordStar.)

There's still a Wordstar resource site: http://www.wordstar.org/
 

Fezzler

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WordStar lives on after a fashion in the Joe editor, which is patterned after WordStar's non-document mode. Pretty much the same keys. There's a version for DOS, Windows and *nix OS-es. The later ones use color and can parse various programming languages. But yeah, I started with Wordstar 0.91 under CP/M in the bad old days. I pretty much stopped with WS 4 for CP/M and DOS. I picked up Wordstar for Windows, but didn't care much for it. For business work, I used WS2000 for several years (very different from standard WordStar.)

There's still a Wordstar resource site: http://www.wordstar.org/

Back in the day, the touch typist loved WS because they didn't have to take fingers off the keyboard. In 20 years kids will say, "what's a keyboard?" LOL. It may be like movable type to us.
 
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