[rescue] Sun 3's... was Re: Need Sun 3/110 RAM and Battery

Jochen Kunz jkunz at unixag-kl.fh-kl.de
Fri Aug 24 16:19:52 CDT 2007

On Fri, 24 Aug 2007 15:46:08 -0400 (EDT)
der Mouse <mouse at Rodents.Montreal.QC.CA> wrote:

> What about -5?  The power supply feeds them -5V as well; what's that
> there for?
I don't know. Is there a -5 V line at all? I dim remember that there is
a -5 V line from the PSU, but it looks like the board doesn't use it.

> Also, if you drop 112V, then it seems to me as though all your
> communication with the world outside the machine is dead, and how
> could you cluster them then?  SCSI networking?
If you use a AUI-MAU with its own PSU like a DEC DELNI you don't need
the 12 V for ethernet. Once the machine is up and running you can access
it via network. So no need for +-12 V for the RS232 either.

Some years ago I mounted an ELC board in an external SCSI box together
with a CDROM, a CDR and a SCSI disk. Makes a nice "CD-Toaster". I feed
+5 V and +12 V from the SCSI box to the ELC board directely. I used a
simple voltge inverter to generate -10 V from the +12 V. No -5 V.

I used the same voltage inverter to supply -12 V to the 4/600MP board in
the 3/60 enclosure. (The 3/60 board doesn't need -12 V, so the PSU
doesn't supply it. The 4/600MP board in contrast needs an external -12 V


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