Quote:
Originally Posted by M0FYA Andy
In my view the transformer in the doghouse PSU was probably designed to operate at 60Hz, with no 'meat on the bone'. As a result they at best run hot and often frizzle.
I recall reading somewhere that at Bletchley Park the operators would put the PSU on the floor and warm their feet on it!
Andy
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Interesting point- I've encountered a few items of US-made professional kit having transformers with dual 115V primaries that despite apparently generously ratings would run fiercely hot and be really brown and crisped after a few years service. I think if I ever had an HRO power supply, I'd be tempted to fit a 12V 5W bulb or the like in series with the primary and use it as a softly-glowing "power on" indicator, just to take the edge off things. Naturally, generous heater wiring and a good sample of rectifier would minimise secondary-side compromise.
4.7nF 1kV ceramic capacitors don't cost too much, also whilst "Y" rated 4.7nF ceramic components aren't necessary here, they would have the voltage margin and are pretty plentiful,
Colin