H786 power supply help wanted

[Paul Anderson]

Hi Charles,

The H786 was standard for the 11/23, BA11-N. The H7861 was for the 11/23+,
BA11-S and had afrw more amps of +5 volts.

I would start by looking at the electronic caps.

I have a few extras here but am pretty busy for the next week or so.

Paul

On Sat, Mar 30, 2019 at 2:25 PM Charles via cctalk <cctalk at classiccmp.org>
wrote:

> I have a PDP-11/23+ and the power supply (H786) "last ran when parked" a
> year or so ago. But there's no DC output at all today, and the fans are
> running so there is AC power...
> I also have the original H7861 that came with it, which had a blown
> chopper
> transistor. I couldn't find anything else bad, so I replaced the
> transistor
> and within a few seconds of running, it blew again. :(
>
> So I need some help - I've never been good at fixing switching supplies,
> not
> to mention the high-side hazards.
> The simplest solution would be just to replace it with a working unit.
> Anyone got one to sell, hopefully cheap? :)
> If not, can anyone fix one or both of mine?
>
> thanks!
> Charles
>
>
>