Microvax II 'primer'?
jules.richardson99 at gmail.com
Mon Jan 22 07:43:33 CST 2018
On 01/21/2018 04:04 PM, Rob Jarratt wrote:
> You might find that the filter capacitor goes up in smoke soon after you
> connect the PSU to the mains, even without powering it on.
Yes, Adrian Graham mentioned that (via FB), too. I seem to have extremely
good luck with the RF filter caps, unlike other people, but I'm always
prepared for the cloud of smoke :-)
> Otherwise it is certainly wise to check the PSU visually for any obviously
> failed electrolytics. If you have one of the DEC load boards you could
> connect the PSU to that as a dummy load. I don't think there is much in the
> way of dependency on the CPU to run the PSU.
At this stage I've got no idea if it's a SMPSU or a linear (I've not popped
the panel off)... I suppose if it's linear then it perhaps doesn't even
need a load to do its thing. If it's a switcher then I expect it'll at
least need something on +5V, and maybe +12V too (unless it has built-in
load resistors to keep the regulation happy, as designs occasionally do).
I see on the output rating label that it lists connection points for
different outputs, so maybe I just need to slap a couple of suitable
resistors onto the +5V and +12V outputs so that they draw an amp or so, and
see how it goes.
> Once you have the machine up and running...
Lets not get ahead of ourselves ;-)
> I am not sure if 4MB is enough to do that though.
Hmm, one of the things that I'm clueless about right now is how the bus
evolved over the years - I've still got a pile of Q-bus boards which I
saved from a recycler last year, and I know there's a 4MB board (made by
Clearpoint, if I remember right) among them. But if that's designed for
earlier PDP hardware then it's possibly no use whatsoever in a Vax world...
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