🚀 go-pugleaf

I posted here a short while back with a problem in a microprocessor-
controlled audio project.  I received some help from several people, and
have the problem fixed.

For reference, I was using two power supplies in the project to keep digital
switching noise out of the audio, but had noise anyway.  The digital side
was being driven by a TI 99/4A supply, and this was the problem.  Not that
it was sub-par per se, it just wasn't designed for the use I needed.  All
+12 volts is not created equal!

The five volt output was clean, but the +12 didn't like to give me the LED
multiplex current pulses I needed, and made a noisy ground plane.  Switching
to optoisolators driven by the TI +5 with a constant-current o-c circuit,
and a small separate six volt supply with an isolated ground cleared this
mess up.

Thought I'd post this to tell folks to watch these small switching power
chassis with multiple outputs; sometimes they bite!

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INTERNET:tindle@ms.uky.edu | "Could you please continue the petty bickering?
BITNET: tindle@ukma.bitnet |  I find it most intriguing."   ---    Data, 
Ken Tindle - Lexington, KY |  Star Trek, The Next Generation, "Haven"
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