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 On Tue, Jun 9, 2020 at 10:19 AM Paul Koning via cctalk < [email protected]> wrote: > > > > On Jun 9, 2020, at 2:59 AM, Josh Dersch via cctalk < > [email protected]> wrote: > > > > Hi all -- > > > > I'm working on a PDP-8/A I picked up at VCF West last summer. After a > lot > > of cleaning and some power supply repair it's showing signs of life (CPU > > seems to be at least minimally functional, core memory is going to need > > some debugging.) > > > > The transformer in the power supply is humming quite loudly, however, and > > I'm curious if this is normal for the 8/A (or is typical for an 8/A of > this > > vintage). I'm used to the supplies in various other DEC machines not > being > > exactly silent but this is a rather severe 60Hz buzz that you can clearly > > hear over the fans when the machine is in operation. > > Assuming these are traditional transformers with laminated sheet iron > cores, check if the rivets or screws holding the laminations together are > loose. If yes, tighten or replace the fastener. > > paul > >
