[SPARCbook] Q: Heat build-up in SPARCbook3 GX "left on 24x7"

[Gary Goddard]

In my local electronic store (Maplin in the UK www.maplin.co.uk ) I saw a
PCMCIA cooling fan (Catalogue code TK51F ).
The packaging stated compatible with windows, but it looked like it just
took its power from the port.
Has anyone tryed one with a sparcbook?

Gary.

----- Original Message -----
From: "Ian Spray" <iws at tadpole.co.uk>
To: <sparcbook at sunhelp.org>
Sent: Tuesday, October 24, 2000 10:10 AM
Subject: RE: [SPARCbook] Q: Heat build-up in SPARCbook3 GX "left on 24x7"


>
> On 23-Oct-00 Ken Hansen wrote:
> >
> > The laptop sits on a hardwood table, with the rear portion "propped up"
> > on those clever little "legs." I am starting to assemble my "lab," and
as
> > such will be moving the machine to some wire shelving in my basement (a
> > relatively cool environment - I am thinking of placing a small 12 V. fan
> > or two (from an AT&T UnixPC) under the SPARCbook to improve air-flow,
has
> > anyone else done such a thing?
> >
> You might also like to try a small fan blowing into the PCMCIA sockets -
> that will try to get air moving around the CPU itself.  Blowing under the
> machine is a good alternative, as the CPU heatsink is thermally bonded to
> the middle of the bottom of the case.  Placing the unit on a wire mesh
rack
> might also help (dunno the make, but similar to the stuff on ER), as the
> large gaps let air move, and keeping the base in contact with the metal
> allows the shelf to become a larger heatsink.
>
> > Also, the laptop has remained open for he last two or three months, and
> > while the display turns off after a period of time (great!), I know I
> > can't close the case, as the keyboard seems to "vent" heat from the
> > system - what are folks doing about this? Do they just leave them open?
> > Didn't someone set some of these up as kiosks? How are you handling heat
> > dissipation?
> >
> There is indeed heat vented from the top of the case.  I would imagine
that
> the kiosk problem is solved by not running SETI at home/dnetc or any other
> process which keeps the CPU 100% active.  I have used a plain S3 (50MHz
> CPU) as a firewall/NAT/router at home, and this summer it was running 24x7
> in an ambient of up to 33C, with the temperature inside the PCMCIA socket
> reaching 44.1C at the worst point.  This was allowing the kernel to clock
> stop to keep the core temperature down, and it was also on a much slower
> machine so the heat generated was much lower too.
>
> I did have two unexplained crashes, but the rest of the time it just
worked
> - there were no external fans but I did leave the screen up to help move
> the heat.  I would not recommend running a machine like this, especially
> not with a PCMCIA modem card in it - pulling that out really was like
> holding a hot potato.  I did make sure that the hard drive was spun down
> after a fairly short time, but that was only because a firewall doesn't
> need much disc access.
>
> > One final question - by leaving my SPARCbook on 24x7, am I damaging the
> > battery? The battery is installed, and the LCD shows battery life
varying
> > between 99% and 100% remaining... Is this drawing power through the
> > battery or working independently? For long-term storage (I have a
> > spare!), should I leave the laptop plugged in and turned off, or should
> > I remove the battery and put it away? I am concerned an internal clock
> > battery will give up the ghost and bring the SPARCbook down, with a
> > broken clock battery...
> >
> The cycling is due to the charging being cut once the microcontroller
> senses the end of charge signal from the battery pack.  After this, the
> cells will start to loose energy as all rechargeable systems do, and once
> it gets below the top threshold, the micro will turn the charging circuit
> back on again.  You're just watching the hysteresis at the end of charge.
>
> I'm not convinced that the main battery has anything to do with the clock
> backup - they're supposed to be independant and self powered.  I do have
to
> add that I haven't read the schematics for the SPARCbook machines, so I
> can't be sure.  I would be very surprised if a dying clock battery were to
> crash the machine though :)
>
>
> --
> Ian Spray          :  Software Engineer     :  Tadpole-RDI
> iws at tadpole.co.uk  :  +44 (0) 1223 428 224  :  http://www.tadpole.com/
>
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