knudsen@ihwpt.ATT.COM (mike knudsen) (09/03/87)
In article <300007@hpfcdq.HP.COM>, vodall@hpfcdq.HP.COM (Bill Vodall) writes: > (I won't comment on a design that leaves 115v on the circuit board with > the switch off.) All "consumer" electronics (like VCRs) does that these days. That doesn't mean I approve of it, either! > to mount the fan on the side of the Coco so it's 2/3's blowing on the regulator > and 1/3 on the transformer. This gives a nice flow of air across all the > ic's and everything runs real cool. Lastly, I build a variable dc supply I had considered for a long time opening up the vents over the transformer -- does seem silly to cover the hottest area. However, the xformer doesn't really get all that hot. The regulator is the big villain, and the RAM chips are what suffer. I got a DC fan for $5 at Rainbowfest, wired it to the under-used negative Coco supply, and just set it on top of the case. Already very cool inside. I intend to mount it on the side like you did, except with the cover on I'll make it SUCK instead of BLOW, so the ICs get the cool air first, instead of blowing the hot regulator's air all over the ICs. If this works, I'll tape over the top vents completely (from the underside) so all air will be drawn in from the bottom vent under the keyboard-- less dust, and NO paper clips falling in anywhere. I already changed from PBJ to Hemphill 512K RAM also, which runs maybe a little cooler. I re-soldered the two little caps when I installed the Hemphill. My problems aren't over, but I think I know where the bug is, and it ain't hardware, but that's another post when I get more evidence. PS: a Razor Saw, a model railroader's best friend that costs only a couple bucks, is much better for case hacking than an Exacto knife. Cuts plastic like cheese. -- Mike J Knudsen ...ihnp4!ihwpt!knudsen Bell Labs(AT&T) Delphi: RAGTIMER CIS: <memory failure, too many digits> "Just say NO to MS-DOS!"