On Thu, 26 Feb 2004, Guo-Rong Koh wrote:

> On Wed, Feb 25, 2004 at 04:04:35PM +0100, Maciej W. Rozycki wrote:
> > On Wed, 25 Feb 2004, Chris Tribo wrote:
> >
> > > 	I believe that the psu fan has some kind of temperature or
> > > rotation sensor system. If the fan is not spinning fast enough it will
> > > kick off. I think there's also a thermal sensor in the CPU itself, but
> > > NetBSD doesn't monitor it I don't believe. I'm probably spouting
> > > conjecture more than actual fact, but hopefully that gets you on your way.
> >
> >  There's a software-readable thermal sensor in the PSU of all DECstation
> > 5000 machines.  It's available as a bit in the CSR in the /200 and in the
> > SIR of the I/O ASIC in the others (therefore the latters can use it as an
> > IRQ source).  The bit is active if an overheating condition happens -- I
> > don't know what temperature it corresponds to (and I'm not that interested
> > in checking it empirically).
> >
> >  I haven't heard of any temperature sensor in any of the processors used
> > for the DECstation.  There may be one outsidew the CPU on the KN04 and
> > KN05 daughtercards as there's a bunch of new registers of littly known
> > purpose in the combined MB/MT ASIC there.
>
> Thanks for information guys.
> I've since pulled the box to shreds and de-dusted it (actually very little
> inside!)
>
> On the overheating track, the PSU fan spins fine, but I noticed that the RZ25
> SCSI drive gets rather hot (too hot to touch in fact).
>
> Additionally, the Motorola branded chips on the CPU daughter board (I'm assuming
> they're the cache?) get way too hot to even lay a finger on.
> I'm wondering if this is normal and whether it might be a good idea to whack a
> heatsink on them?

	My 5000/25 has chips made by Performance Semiconductor that look
like next to the motorola cache.
http://vaxbase.openecs.org/PersonalDECstation5000-25/preview_PDEC500025-4.jpg

	I don't remember my system getting much more than warm, maybe the
ps is overvolt/undervolt?


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