The PDP11/04 has landed..

Mattis Lind mattislind at
Mon Feb 8 10:20:22 CST 2016

2016-02-08 16:25 GMT+01:00 tony duell <ard at>:

> >
> > I have one of these on my restoration list. I know the PSU does not
> work, and that others
> > have tried to fix it before me, who probably know PSUs much better than
> I do. It has core
> >  memory so I really would like to get his one fixed. I have never seen a
> PSU for it come
> >  available in the UK or Europe, so it looks like it won't be an easy
> job. :-(
> Which mounting box is it? (The 11/04 could certainly come in 5.25" and
> 10.5" versions, there
> may have been several versions of each). The common 10.5" one, BA11-K
> IIRC, is a fairly
> easy supply to work on, it's a big mains transformer and the DEC switching
> regulator bricks.
> The common 5.25" one, with the H777 PSU, is a bit more nasty, the H777 is
> a normal-ish
> SMPSU. I have worked on both.

The H765 PSU in the BA11-K and the H777 supply in the BA11-L are fairly
similar. Both have a big mains transformer. Both have the switchers on the
low voltage side, so they are fairly easy to work with both of them. The
big advantage with the H765 is the modular design.

> -tony

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