PDP-8/A transformer hum

Paul Koning paulkoning at comcast.net
Tue Jun 9 09:35:12 CDT 2020

> On Jun 9, 2020, at 10:27 AM, Anders Nelson via cctalk <cctalk at classiccmp.org> wrote:
> Related question: Is there any reason, other than historical accuracy and
> cost, to not replace the power supplies in vintage computers with modern
> switching power supplies?
> --
> Anders Nelson

RFI?  Old computers are not well shielded, and putting a switcher into them might well create significant radio interference.  It may be ok if the power supply is a well shielded subsystem.

Also watch out for minimum load.  Classic power supplies don't mind being unloaded; switching supplies often need a minimum load current to keep them healthy.  It's probably ok but it is a new consideration.


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