[Info-vax] DS10L releases magic noise

[John Wallace]

On Apr 20, 2:38 pm, koeh... at eisner.nospam.encompasserve.org (Bob
Koehler) wrote:
> In article <4f90b4a0$0$397$c3e8da3$4db35... at news.astraweb.com>, JF Mezei <jfmezei.spam... at vaxination.ca> writes:
>
> > Bob Koehler wrote:
>
> >>    The VT on the same power strip came up with no problem.  No
> >>    serial data is exchanged.
>
> > When you plug the computer in (with power button pressed) does it do any
> > noise ? Can you see/hear any sparks at the plug as you insert it
> > (showing some current flowing in) ?
>
>    Quite and dark.
>
>
>
> > If the sequence to access the RMC isn't working, I suspect the power
> > supply is really fried.
>
>    Out of the chassis, it is producing 5V on the disk power connectors,
>    and 0.082V on lots of other connectors.
>
>    Disassembled, there are no obvious blown parts.
>
>    I'm going to check the physical switch at the front of the chassis,
>    and if it's OK, I plan to trace it's wires and the 120V wires to see
>    if I can figure out which component is actually a relay.
>
> > RMC is powered by a mini power supply that is always on (within the
> > larger power supply).
>
> > Have you contacted david at islandco ? he would have spare power
> > supplies and/or spare DS10Ls.
>
>    Not yet, but I am aware he may be a second source.

Does "out of the chassis" also mean disconnected from its low voltage
wiring? Apologies if the following is already known to you...

As a general rule, it is not helpful to measure the outputs from a
modern switched mode power supply unless representative loads are
connected, to make the thing actually switch properly. It is not like
disconnecting an old linear regulated power supply.

The other factor to consider is how any control inputs to the PSU
behave - even if you had realistic loads, are any control inputs
needed to make the PSU "turn on".

Best of luck anyway, and apologies if this has already been considered
and/or is irrelevant.