[Coco] Adding a CoCo 2 Case Fan

[Gene Heskett]

On Friday 18 April 2008, Chad H wrote:
>I was wondering how those of you who have installed cooling fans in your
>original CoCo cases have done this.  Where did you draw the power?  Using a
>multimeter I measured the A/C transformer output at approximately 18VAC, not
>a common type for fans.  I'm considering doing one more mod to my CoCo by
>taking a 40mm fan and placing it just inside the left side of the case,
>receded out of site, and blowing right over the heat sink that seems to be
>the hottest thing in the case.  Since I couldn't determine a power source
>safe to use off of the CoCo motherboard, I'm considering taking a small A/C
>to 12VDC board and mounting it inside the case and running the A/C inputs to
>a switch by the fan and the same A/C input leads used by the CoCo
>transformer.
>
>
>
>I would like very much to hear the ideas other have come up with on this.

I put a 90mm fan smack in the top center blowing out, and powered it from the 
DC end of that power diode that feeds the transistor on that heat sink, its 
about 9 volts there & the fan will run quietly and forever.  That was a coco2 
and it sat there, 24/7/365 for 13 years at the tv station, acting like it was 
a $20,000 Grass Valley Group EDISK accessory for a GVG 300-3A/B video 
switcher.  It blew two disk controllers and wore out several drives in that 
time but no trouble with the coco2. I'd put in the 'The forgotten Chip' mod, 
and it did that job 4x faster than GVG's gismo, giving the tech operators 
regular os9 filenames instead of 2 digit hexidecimal filenames.  When the GVG 
switcher finally gave up the ghost cuz we couldn't get the custom IC's to 
service it anymore, they gave it back to me and I still have it.

My main coco3 doesn't have a fan and doesn't need one.  With a disto 2 meg kit 
and a 6309, and powered from a std AT power supply, it generates so little 
heat I can toss a furniture blanket over it. 2 degrees rise above the memory 
isn't much heat...  There would not be room in the coco3 for a fan in that 
location anyway, memory is in the way unless it is a 128k model.  The one 
coco3 I did put a fan in got one of those teeny 1.5" thingies in the left 
end, blowing out, which helped quite a bit.  Tapped power from the same place 
for it.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
"Marriage is like a cage; one sees the birds outside desperate to get in, and 
those inside desperate to get out."
-- Montaigne