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Old 6th Jul 2019, 11:10 am   #3
TrevorG3VLF
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Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
Posts: 1,378
Default Re: Vintage IBM school clock.

Problems
1. You could make oak doughnut to fix it to the wall.
2. You could fit a 230V to 115V transformer to get the right voltage. This could fit in the doughnut.
3. You could try a resistor to drop the voltage but would need to provide thermal and electrical insulation.
4.If the clock has a synchronus motor intended to be run on 60Hz, then the clock will run slow. You will need to make a circuit to provide an accurate 60Hz at 115V. This can be done by phase locking a 300Hz oscillator to the 50Hz and dividing this by 5 to get 60Hz.
5. Alternatively rip out the original works and replace with a quartz controlled system.
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