gunrunnerjohn posted:One interesting twist on this power supply mod would be to just add a delay relay to the output pins, say a one second delay after power is turned on. This would make it automatic and no extra button pushing required.
I haven't noticed any power blip on these when turning off, but it certainly has one when turning on.
The delay relay sounds like a good suggestion John, I hadn't thought of that. But I kind of like the idea of manually connecting and disconnection the load, so I am happy with way it is now. I guess you could also use a conventional latching style relay in place of this setup. I think I have a couple of P&B latching relays kicking around somewhere, but I think they are 120vac types. Using one of them would eliminate the need for the wallwart though, but then you are switching 120 vac with the pushbuttons. I think the way I have done it is likely safer.
The kind of blip I was referring to would be a power interruption external to the PS, the kind of momentary flicker that you get during a thunderstorm for instance. Hopefully the relay would drop out and prevent the PS from powering up again with the load connected.
BTW, does anyone know what component typically toasts when these switching type PS's go on the blink? I kind of vaguely recall that being discussed in a similar thread back a year or two ago. It might be simple enough to source and replace the component if you knew what to look for, but I have no idea where you would scare up a schematic for these things.
Also I should mention another alternative that rtr12 suggested was moving the NC Disconnect pushbutton to just ahead of the Connect pushbutton, in the wire to the actuation coil. This was apparently another way that they did these things back during his working career.
Rod
