31 Mar
2009
31 Mar
'09
1:41 p.m.
This is supposed to feed an expanded PCjr that has two
power inputs. It
looks like somebody broke open two PCjr power bricks and wired them in
parallel to one line cord, then glued the bottom of the exposed bricks
to keep them from bouncing around in the metal enclosure.
To me, this looks really ugly, and I'm suprised that somebody went to
this depth. The frames of the transformers were grounded, but the box
itself was not grounded.
Well I certainly wouldn't leave it that way.
I like the concept, I just don't like the way it was executed. It will
never look pretty, but is there a way to make it safe? Is it enough to
secure the transformers to the box in a more robust way, and then
connect the box to the ground, or should I just be thinking about
recycling the components?
As far as I know, the transformers are good. In which case you might as
well use them.
Waht I would do is take the transformers off the bases of the original
power bricks. There seems to a be a fuse on each base too, if that fuse
holder can be removed (that is, it's not part of the mulded base), then use
it, otherwise buy a new fuse holder (they're easy to get).
Mount the trasnformers in the metal box. I'd use 4 tapped spacers and
suitable screws to hold each one down. Connect a fuse in series with each
primary winding, then to the mains (in the obvious way). Earth the box to
mains earth. IIRC, the secondary windings should be totally isolated from
earth (they go to the outside pins on the power conenctor), the central
pin on the power connector goes to mains earth.
-tony