Stuck key on a II plus

I've had some luck by using (alternating) DeOxit D5 and DeOxit F5 (Fader Lube) on the old DC51 switches. It could be that switches are making false contact and the matrix is corrupt. THis also happened to me when I didn't allow a switch sufficient time to dry outafter cleaning it. You need to place the switches in a warm, dry place for no less than a week after cleaning them, as the design allows moisture to cing to the contact sandwich for a very long time. I would not use a hot air gun or anything else on them, nor expost them to temperatures over 40C/105F for more than an hour or two at a time, as this could warp them. 

I also do not advise using any other products. I have used a number of contactor cleaners, alcohol, and other solvents, and the only process that I have been able to use to produce reliable results is by using the DeoXit D5 cleaner, cycing the switch for 100 presses, and immeiately using the DeOxit F5 fader lube and repeating immediately thereafter. 

It's a very time-involved process. I spray a switch full of D5, then press it 100 times, then repeat with the F5, 100 times. If it is still slightly sticky, then I I do it over again. Then  let it sit overnight, and repeat the process. If the switch then returns properly, I let it  dry for at least one week  and test again; and only then will I rule it working. This process can also clean the contacts on non-responsive switches. It is not possible to rebuild the DC51/DC50 series switches, as far as I can tell, and I have a drawer of switches that I was not able to get to spring fully back up.

If a switch seems mostly free after drying, but occasionally sticks, I start the process over. The improvement is a sign that the switch may come bac to life after a second entire treatment, but some switches just never come bac to life, and if it sticks slightly when used on its own, once you put a keycap on it, the extra weight will guarantee a stuck key. 

You can also put little coil springs around the post, but you will need to order them from a spring company by measuring the post and determining the desired tension. They need to be small enough that you can coil wrap them around the keystem, and put pressure around the diamond shaped head of the stem, and the base of the keyswitch.

Cone shaped springs, IMO, tend to work best, but I did not like the added pressure requirements doing this. 

I have had to buy partial Datanetics KBs and loose switches to use as parts, and even then, I had some of the switches split open. I managed to save one of those that did, but the reset switch stopped functioning after it split, so I once again must take the original ][ apart and replace that one; also the 8 key as it is not 100% responsive, which is a rather large issue as it is needed to produce parens and of course dec / hex values. 

I advise placing a very small droplet of super glue on the black box of the switch, along its seams, to prevent them splitting open on you. Dab it on with a stick applicator, right on the seam, but not near the post, as you do not want to glue it into any one position. Once the eys split open, you have a very low chance of salvaging them. I was lucky with one, but I have five others that split on removing them from a parts board, so now I now to glue them first, ere desoldering them. This was not a heat issue, just age. I ordered some from eBay and some arrived split open just from giggling about in the post, so I now consider the seam seal a wise. prophylactic measure. 

If another Datanetics parts board shows up, and I end up with extra switches, I might offer a few. Only buy switches where the legs are intact! Fixing a broken leg on the DC51 means opening the switch, which I have never found to be an option. Likewise, if you eend up buying another Datanetics unit, I would appreciate getting some switches, and also two specific keycaps. I somehow misplaced one cap during the cleaning process, and the S cap had been glued to its original keyswitch stem, and I have not been able to dremmel out the cross hole. I did replace them with the Mk2 caps, which looks generally fine, but they are shorter and this makes typing non-uniform. 

There is also now a kit available to replace the Apple 1 and original Apple ][ keyboard, and in the coming months I will be building a few and offering some as pre-built units. It is not visually identical (the keys are grey, not brown), but it is marked properly and it uses modern keyswitches, so it's a very good option in a world where supply of Datanetics parts is running out. 

First of all, for Datanetics keyboards usually if there isn't something mecahnically wrong with the switch you can revive them, but here is the trick.  Remove the bad switch and then FLOOD it with ISP using a pipette on each quarter of the switch moving the plunger to the extremes so that you have a spot to get the ISP inside the switch.  Then work the key up and down using a needle nose plyers not just pressing it.  This aggitates it more to get rid of the junk.  Repeat the ISP flooding to flush out all the junk.  Repeat if necessary and wait for the key to dry to test.   The other trick is that if you don't remove it from the keyboard, you must remove the screw underneath otherwise the junk inside the switch has no place to go.  Be careful though, if the switch has weak solder connection wires, they could break.  Then again if they were that weak the swtich should be replaced anyway.

Cheers,

Corey

I think ISP will be isopropyl alcohol, also called isopropanol.

Edited to add: you want the 99.9% pure isopropyl alcohol.

fstark wrote:

Thanks to both of you Timelord and Corey986 for all this info.

 

I am not in a hurry to fix the keyboard.

 

I read about DeOxit, but this looks hard to find in Europe (and pretty expensive, like US$30 to $40 for 5oz). I was hoping that there was an equivalent here. No free lunch, I'll bite the bullet!

I am not 100% clear on your procedure: do I need t

You need not remove the keyswitch unless you need to replace it, but be aware that you need to wait a olly long tie for it to dry. I have been through this several times. 

I do not agree with the 99.9 IPA solution. I have tried this and had little success: it does not free or luvricate stuck switches. 

I pay a fortune for DeOxit. It is a key compound for this type of restoration. If you do no care about factory KB, I may be willing to trade out a newly made B for the Datanetics as a whole. Otherwise, you are in the same boat as I am, and all users with very early ][ or 1 machines, and you need to suffer with the costs and consequences

I advide buying a twin pair of DeOxit D55 and F5, as this will save you freight and other costs. It is prudent to have a supply of both on hand.  

Building up a stock of DC5x switches is the only other option, and it is equally costly. I was fortunate to find a board ith 20 switches for a decent price, only to discover that half of them did not meet my qualifications   for 'good'. More than half were faulty, but the pricew that I paid evened out so that even with half of them faulty, I could use the rest. I literally only have enough switches to fix my immediate issues, and if any occur past that, then I am fek'd. If I did not hae a model 1/2 Datanetics board, I would not bother with it. 

FWIW, you can swap out your Datanetic KB with a ][+ KB. If you find one with early switches (tan/brown, not dark brown), then there will be no visible difference, and there are some of those on eBay.  I also have at least one of them, if you want to do a swap. 

Where are you located?

If you end up needing only one switch, I may be able to find one, but with freight you are looing at over twenty euros for just one, and there is never a guarantee that it will be better (unless it comes from my restored spares, which is too small a stockpile to sell off any). 

Please keep me updated on your progress. You should not need to suffer with REPT not working. You are lucer than I was, as I had to replace about twenty keyswitches and restore almost every other one. Only about six of mine worked properly after sitting for 40 years!