Restoring Master/Electron keyswitches

discuss both original and modern hardware for the bbc micro/electron
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retroclinic
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Restoring Master/Electron keyswitches

Post by retroclinic » Tue Apr 29, 2014 5:30 pm

Ok, I had reservations if this would work, but I kept all the old dead keyswitches I've been removing from Masters, and today tried them in an ultrasonic cleaner, with the proper cleaning fluid.

I soaked them for about 10 mins first, then ran the ultrasonics for 3 minutes at a time, giving them a 10 min break inbetween. Repeated that half a dozen times.
IMG_1881.JPG
After rinsing and drying the first batch out, 4 out of 5 have come back to life and work perfectly! :shock:

I'll repeat the process on the failures, puls I've got several other batches to do, so we'll see how the rest of them work, but this should save throwing them out and ravaging so many Elks!

Mark.
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paulv
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Re: Restoring Master/Electron keyswitches

Post by paulv » Tue Apr 29, 2014 5:33 pm

How cool is that! =D> =D>

Paul

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flaxcottage
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Re: Restoring Master/Electron keyswitches

Post by flaxcottage » Tue Apr 29, 2014 5:52 pm

Nice piece of kit, Mark. 8) =D> :D
- John

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retroclinic
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Re: Restoring Master/Electron keyswitches

Post by retroclinic » Tue Apr 29, 2014 5:59 pm

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DutchAcorn
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Re: Restoring Master/Electron keyswitches

Post by DutchAcorn » Tue Apr 29, 2014 6:15 pm

I have repaired a few BBC Master keyswitches last week (100% success ratio so far). Since I do not have spares I was forced to go for repairs.

Starting with the Classic Acorn guide I found that I could not "part the two halves" because they were glued together.

The two pins that I removed were very obviously black though and after scratching them clean with a hobby knife the switch worked perfectly. Repeated that successfully four times so far.
Paul

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Re: Restoring Master/Electron keyswitches

Post by daveejhitchins » Tue Apr 29, 2014 7:02 pm

retroclinic wrote:but this should save throwing them out and ravaging so many Elks!

Mark.
=D> =D> =D>

Well done Mark . . . The Elks are a little safer now :lol:

I'll have to give this a go. I already have an ultrasonic bath. I think it's an actual Staedtler unit. I used it to clean plotter pens when preparing PCB artwork. RobC now has the plotter, I hope it still works for him OK?

Dave H :D

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DutchAcorn
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Re: Restoring Master/Electron keyswitches

Post by DutchAcorn » Tue Apr 29, 2014 7:16 pm

retroclinic wrote:Ok, I had reservations if this would work, but I kept all the old dead keyswitches I've been removing from Masters, and today tried them in an ultrasonic cleaner, with the proper cleaning fluid.
At the risk of being called a party pooper; 8BS also has a page on restoring keyboards and post the following warning:

"Wash the switch in isopropyl alcohol, or replace it with a known working switch (I would recommend replacement unless you really enjoy desoldering keyswitches that you think were fixed and clap out in 2 days time)."

In other words: are you certain this is not a temporary fix?


Paul
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retroclinic
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Re: Restoring Master/Electron keyswitches

Post by retroclinic » Tue Apr 29, 2014 7:27 pm

DutchAcorn wrote:
retroclinic wrote:Ok, I had reservations if this would work, but I kept all the old dead keyswitches I've been removing from Masters, and today tried them in an ultrasonic cleaner, with the proper cleaning fluid.
At the risk of being called a party pooper; 8BS also has a page on restoring keyboards and post the following warning:

"Wash the switch in isopropyl alcohol, or replace it with a known working switch (I would recommend replacement unless you really enjoy desoldering keyswitches that you think were fixed and clap out in 2 days time)."

In other words: are you certain this is not a temporary fix?


Paul
Well, time will tell. I'm using a few of them in refurbished keyboards I'm doing now. It should be a permanent fix, because of what is happening. The ultrasonic method cleans dirt off the metal parts of the switch, by creating very tiny bubbles on the surface of the metal that pushes the dirt off.

http://en.wikipedia.org/wiki/Ultrasonic_cleaning

Washing it in IPA isn't going to do anything, as IPA will not remove the tarnish from the internal parts that actually make the contact.

Mark.
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stevendt
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Re: Restoring Master/Electron keyswitches

Post by stevendt » Wed Apr 29, 2015 12:46 am

OK, this is an old thread, but, people might find this useful......

http://deskthority.net/wiki/Futaba_low-profile_linear

Good description of the key-switches, disassembly, reassembly and some good photos of the parts

regards
Dave

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Re: Restoring Master/Electron keyswitches

Post by richardtoohey » Wed Apr 29, 2015 6:14 am

stevendt wrote:OK, this is an old thread
I think you'll find that just about everything around here is old! :lol:

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