Mac Plus cooling

[Osgeld]

i would still be leery of driving any motor off of a port, they are not generally made for decent amperage, and putting your finger on a decent fan can draw double digit amps, yea that is a extreme worst case, but when connecting it to a port made to deal with at best a few hundred miliamps...

edit: plus the electrical noise, and reverse emf, and becoming an ac generator when spinning down and ... just use drive power (imo)

 

[Mac128]

i would still be leery of driving any motor off of a port, ...becoming an ac generator when spinning down

The 400/800/1440K drive which is powered off of the floppy port, and it is essentially a motor that can be very active during file transfers. I've never seen a sticky drive overload the bus, so there must be safeguards in place, since common disk accidents would damage the Mac in the way you suggest and I just never saw that happen. And the port can only power a DC fan.

The serial port was never designed to run a drive, so I would be more concerned about running a motor off of that.

Plus, I'm not sure how using a port as a power source is any different than the common practice of taping into various power access points inside the Mac to power internal AC & DC fans.

 

[Osgeld]

port = connection to some other logic device, serial printer whatever, connect a inductive load to logic and see how much it can handle }

drives usually connect to the power supply in a direct fashion, and yea tap away if it looks like something you can drive a lamp from, that is why power supplies have lots of beefy caps and large diodes

macs of course dont have different floppy power connectors, they just pipe the power up the ribbon cable but its connected to the power supply, I always kinda thought it was shady that 30guage wire has a lot of resistance and can only handle ~800ma before it vaporizes somewhere

 

[Quadraman]

Convection cooling was such a monumentally bad idea that Jobs brought it back in the G3 iMacs.

It only goes to show that a bad idea isn't bad when the boss thinks of it. 8-o

 

[Bunsen]

port = connection to some other logic device, serial printer whatever, connect a inductive load to logic and see how much it can handle

The 400/800/1440K drive which is powered off of the floppy port

So it would be no different tapping the 12V supply off that, than tapping the one off the internal floppy, surely.

 

[Osgeld]

depends like I said the power is on the ribbon cable, has a max of ~800ma for the wire, who knows what the port can really handle, whats the floppy drive suck down, whats the fan suck down?

mac's especially early ones, have pathetic current sources available to the user, your gamble

 

[Mac128]

Convection cooling was such a monumentally bad idea that Jobs brought it back in the G3 iMacs.

I don't recall any serious problems with the iMac. I have a friend with one of the original iMacs that is crammed into a cluttered corner in an un-airconditioned house and it's still going strong today, never having had a repair.

I have a Plus built with the proper SE grade components in 1990 which has never had a repair and is still going strong, despite having been used during its most productive years in a tiny un-airconditioned office surrounded by clutter.

None of the original PowerBooks ever had a fan. In fact I have a PowerBook Duo 2300 that has never had a repair and is still going strong.

Televisions, particularly the early ones which were crammed with vacuum tubes and heated up like ovens, never had fans. My grandmother had a particularly well made Magnavox from the 60s, that ran hotter than any compact I ever felt, which ran flawlessly for over 40 years.

If a product was designed to facilitate convection or conductive cooling, there is no reason to consider it a bad idea. The compact seemed to have been adequately designed to handle this type of cooling. The problem was cheaper underpowered components than specified (thanks to bottom-line Sculley) and to a lesser degree, improper use.

 

[AdonVonPanzern]

Honestly the beat you could do on the cheep is take a few slim 40mm fans and build a air router type thing with a breadboard and a spare switch it’s basically what i did when i was in Florida fixing a friends mac plus.

 

[JDW]

...take a few slim 40mm fans...

In my experience, the slim fans, especially those smaller than 60mm don't move that much air.  To move even a reasonable amount with them would mean choosing one with a high RPM that would be quite noisy.  But I as mentioned in my Compact Mac Fan Video last month, the Macintosh 128k through the Plus really don't need a fan unless you have upgrades.  So long as you have a stock machine with adequate room cooling (you want to stay cool in the summer too), and so long as the machine is recapped (I'm actually making a video on that now), the machine will in most cases be just fine.  And even when you do have upgrades, the Larry Pina approach of facing an external floor fan on the machine is one effective way to keep it cool, without any internal hacks.