Acorn Electron 36951 restoration
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I bought this Electron 30 years ago when they were selling them off at a really low price, fairly certain that I paid £30 for it. It was sold as 'Brand New In Box', and it came with a new cassette recorder. I never actually opened it back then, a small error on my part! On opening, it looked clean until I took the case apart, the keyboard keys were clean but under them was a good few months of fluff and dust accumulated, initial test showed a large number of keys were unresponsive. So, first job was to completely strip the keyboard, switches desoldered, etc, and clean all switches, phase 1 in ultrasonic bath then phase 2 treatment with DeOxit, etc. My other Electron restoration project (39870) goes into more detail on this. After reassembly the keyboard PCB was coated in Ambersil Conformal coating. |
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Next I turned to the PSU, this looked like it had seen some rework, badly recoated solder mask including someone's fingerprint. I carried out a full recap of electrolytics, a good clean then a full recoat of soldermask. I know I have also coated the solder joints but the coating is easy to remove should access be needed to the joints.
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Main board was fully recapped, electrolytics and tantalums, board cleaned, all connectors treated with DeOxit then retested. At this point it seemed that tapping the board caused it to reset, traced to a misbehaving CPU socket, I changed the socket and all was well, for completeness I cleaned all socketed IC's and treated all the sockets with DeOxit. On retest now fully stable. Main board now coated with Ambersil Conformal Coating. Before putting it in the case I added heatsinks to the ULA and the 6502 as they were the only 2 IC's rising much above room temperature. |
Reassembled, all PSU voltages check OK
Testing:
All keys very responsive, no contact bounce or intermittent contacts
RGB socket: good signal with my RGB-SCART cable
Power socket and Original PSU brick tested OK
Cassette port: tested with my Acorn Data Recorder, save and load OK.
RF output: worked but my modern TV does not like the dirty signal from these modulators! but at least I got a workable picture
Video output: worked fine but mono so added LK4 to add the colour back in. Note: the mono output is far crisper than with the colour signal mixed back in.
Edge connector: Thoroughly cleaned and treated with DeOxit. Then tested with my elkSD128 cartridge.
All keys very responsive, no contact bounce or intermittent contacts
RGB socket: good signal with my RGB-SCART cable
Power socket and Original PSU brick tested OK
Cassette port: tested with my Acorn Data Recorder, save and load OK.
RF output: worked but my modern TV does not like the dirty signal from these modulators! but at least I got a workable picture
Video output: worked fine but mono so added LK4 to add the colour back in. Note: the mono output is far crisper than with the colour signal mixed back in.
Edge connector: Thoroughly cleaned and treated with DeOxit. Then tested with my elkSD128 cartridge.
Cassette recorder
This actually was brand new in box, didn't help it work though!
Both drive belts were no longer rubber so once I changed these all was well. This is the cassette recorder used in the tests above.
This actually was brand new in box, didn't help it work though!
Both drive belts were no longer rubber so once I changed these all was well. This is the cassette recorder used in the tests above.
