[SunRescue] Sparc 10 fan upgrades (was cheap thrills...)

[James Lockwood]

On Tue, 13 Jul 1999 firststep at clara.net wrote:

> New user here trying to get IPX and gear together. This sort of stuff
> will certainly help me in the coming weeks to get up and running.
> 
> More like this please.

Ok, here's another helpful tweak:

Those of you with Sparc 10's and 20's probably already know your biggest
enemy: heat.  With multiple high-powered CPU's and 4 sbus slots, these
machines can cook themselves in short order if they're not taken care of.

Sparc 20's have 2 fans built into the powersupply to cool the CPU's and
cards.  Properly maintained ones should have an additional small fan in
front of the drive bays.  This makes them evenly cooled, but marginal
with hot CPU's.

Sparc 10's have 3 fans built into the powersupply, and a baffle attached
to the case lid helps direct air from all 3 over the motherboard.  This
sounds great until you realize that your hard drives are getting no
cooling.  Older 5400RPM models can handle this with only normal convective
action, but most newer drives require some sort of forced-air cooling.

Fortunately, it's easy to fix this problem, if you are willing to accept
the loss of the floppy drive.  Procure a high-flow 50x50mm box fan (the
front auxiliary fan from a Sparc 2 is the perfect size).  Using normal
PC-style powersupply splitter cables, split the power from one of the
drive bays and connect the +12V and ground pins to the power pins of the
fan.  If you get a fan with the right style of mating connector,
everything will just plug right in.  Using a 1" long piece of double-stick
tape, mount the fan near where the back of the floppy drive once sat (at
one corner of the floppy bay "well", about 2" away from the middle of the
drive). A small piece of double-stick tape is also useful for holding down
the power cables in that area so they don't obstruct airflow. 

Power up and make sure that you are moving air, then put your hotter drive
in and check the temperature every couple of minutes.  Keep in mind that
you'll need to leave the case lid installed for best cooling.  I've been
able to run hot 7200RPM 4GB drives in my SS10 in 80F ambient air, and they
are only warm to the touch.  The case lid just touches my fan when it
closes, holding everything in place.

-James