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Old 22nd Mar 2021, 7:09 pm   #220
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,154
Default Re: I found it! A very sorry looking MK14.

On my original MK14 prototype I only added the decoupling capacitors on the SoC schematic, and it worked well enough, although when I looked at the waveforms on the power rails or any signal they were noisy as anything, so much that I wondered at it working at all, which is why when I produced the second version (1.2) I added as may decoupling caps as possible, as others had requested. I reasoned I could always leave them out, but they are so cheap I just populated all of them.
The big electrolytic seems mostly decorative these days, but I guess that depends on the power supply you plug in. Most of the "wall wart" power supplies I owned in the 70s/80s had hardly any smoothing as you could always hear hum when I powered my radio or cassette player from them, so I imagine SoC put them in to stabilise a less-than-stellar "battery eliminator" as we used to call them.
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