Acorn Atom replica build (23rd June 2024)
As an interim to building an actual Atom clone I decided to try one of the 'replica' options, this one from Chris Oddy, designed to fit into an Acorn Electron case, which by pure coincidence I had a spare one.
First step was to strip an existing (broken) Acorn Electron for the key switches, when individually tested I would say that about half did not work, or at least not test well, so, I went down the path of partially dismantling each keyswitch and cleaning the contact posts.
First step was to strip an existing (broken) Acorn Electron for the key switches, when individually tested I would say that about half did not work, or at least not test well, so, I went down the path of partially dismantling each keyswitch and cleaning the contact posts.
I use 2 pin vices for this and unscrew the posts, spray contact cleaner into the switch itself and clean the posts with a cotton bud and De-Oxit D5 (red) contact cleaner, then reassemble. I generally aim for a contact resistance of 0.01 ohms, any higher than this and I remove the posts again and completely strip the switch. Inside I clean the pair of gold flashed contact springs with DeOxit Gold and a really small cotton bud, then reassemble and retest.
I use 2 pin vices for this and unscrew the posts, spray contact cleaner into the switch itself and clean the posts with a cotton bud and De-Oxit D5 (red) contact cleaner, then reassemble. I generally aim for a contact resistance of 0.01 ohms, any higher than this and I remove the posts again and completely strip the switch. Inside I clean the pair of gold flashed contact springs with DeOxit Gold and a really small cotton bud, then reassemble and retest.
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Time to construct the keyboard, I drilled and filed the new holes for the extra 4/5 keyswitches, then sprayed it matt black to avoid the aluminium plate showing through. [b1] |
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I then dry fit all the keyswitches and soldered them up in 2 phases, the first phase was all those in the original layout as I knew those positions were accurate, the second phase was to add each of the 5 new positions making sure of the alignment before soldering each one. |
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I also preferred the look of BBC model B keytops so used those instead of the Electron ones. |
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