Is using an external fan needed with a Mac Plus?

[dbraverman88]

I recently obtained a Mac Plus (Yay!). It's beautiful. It came with a Kensignton Macsaver surgesupressor with a built in fan. it fits in nicely at the top of the Mac Plus and the fan works to cool it. But is it necessary to run a fan like this? Won't the convection cooling of the Mac Plus work as designed by Apple? What attracted me to the Mac Plus is that it is quiet. (BTW: I am working on getting the Mac Plus to boot and run entirely from 100MB Zip drives.) This fan sounds like a vacuum cleaner. What are people's thoughts on using an external fans with a Mac Plus. I don't want to shorten its life, but I want it quiet too.

--David

 

[TheNeil]

It should run fine as, like you say, that's how it's designed to work. However it's a vintage piece of computing that's no doubt busted a gut time and time again so giving it a little helping hand to keep cool certainly won't do it any harm

I'd have a look at the surge suppressor and see if there's anything you can do to quieten that down (maybe a quick clean and/or re-lube of the fan bearings/sleeve might work wonders). If you're running the Plus in a well ventilated room anyway (and you can live with the risk of 'surges') then you should be fine to ditch it and go back to the sanity of silence. If it's really noisy though and you still want to try to cool things down, you should be able to hook up a more modern (i.e. quieter) fan, possibly inside the case to keep things neat and tidy

 

[equill]

Alternatively, there is the consideration that the fanless design of the 128K to Plus machines was an aberration from the outset, well illustrated by the existence of aftermarket offerings such as the Kensington System Saver, the name of which alone is testimony to the real-life performance of the Macs concerned.

I use my 512Ke much less than I should wish to do simply because it is fanless. The bucket above the analogue board is not louvred, and that part of the case gets damned hot. Not warm, as CRT iMacs do, but hot. The convection path from the bottom slots in the sidewalls of the bucket to the 'chimney' in the handle does not ensure that air is swept across the power/sweep board components, but centrally up and around the CRT. There is a definable stagnant 'well' of hot air in the top of the internal space that is not easily replaced. I have long contemplated addition of active ventilation to my Mac. The flat-box Kensingtons are rarely offered on eBay, and those that are are for 120V North American mains supplies.

I have my Mac apart at the moment to add a Dove SCSI card. Since I have chosen not to use Dove's placement of the SCSI port in the cover above the battery, I have accepted that I may as well also make another hole in the bucket for a 12-V fan exhaust, and make slots in the bucket above the FBT. I suggest that you accept your good fortune in getting a Kensington unit, and explore replacement of the present fan with a modern quiet unit. Trawl these Forums, or PM jdw directly for advice about his source of quiet high-efficiency fans. You can easily substitute the Kensington's surge-suppression with a power-board containing a surge suppressor, but the fan is a potential lifesaver for your Plus.

de

 

[Scott Baret]

Do some research on the Mac Chimney...supposedly the best way to cool them. Mac Bible should explain it for you if you get an earlier edition. It's basically exactly what the name says--a big chimney for the top of the Mac to cool it down!

 

[MacMan]

Mac Bible 3 describes the Mac Chimney well; basically it's a cardboard, pitched "roof" that fits on the Mac with a foot long card chimney in the middle. This helps draw air up through the Mac and improves ventilation - silently!

 

[tomlee59]

Won't the convection cooling of the Mac Plus work as designed by Apple?

That's the problem. It does, which isn't the same as "well." The decision for convection cooling was done mainly by fiat, not as the result of any careful engineering analysis. Jobs didn't want the noise, so no fan, heat be damned.

The only silver lining was that it created an opportunity for third-party suppliers to sell products like the Chimney, System Saver, and other accessories.

 

[dbraverman88]

Everyone,

Thank you for your comments. The overwhelming consensus clearly agrees the Mac Plus benefits from some additional cooling. I thought about placing the Plus on a cooling base designed for laptops. Without performing a proper analysis, I would expect it to be not as effective as a side or rear mounted fan (requiring a case modification) or a fan at the top. The heat generating elements of a laptop are approximately coplaner while the elements in a Plus are distributed within a space.

I think I will use the Kensignton unit. I can always disconnect it for a short time when I need silence.

--David

 

[Quadraman]

Unfortunately, the "convection" cooling does not work nearly as well as it does in the slot load G3 iMacs. It draws air in from the sides and that air rises up the sides as it gets heated and exits through the handle when it reaches the top, but it is as equill said, there is a huge area in the middle that gets missed by the flow of air entirely. Many a compact has succumbed to the ravages of heat build up because of Jobs decision not to have a cooling fan. I only run mine for occasional testing as I don't have any fans to keep them cool or I would use them a bit more.

 

[dbraverman88]

Trawl these Forums, or PM jdw directly for advice about his source of quiet high-efficiency fans.de

Thanks for the suggestion. This will be added to my project list.

--David

 

[dbraverman88]

The bucket above the analogue board is not louvred, and that part of the case gets damned hot. Not warm, as CRT iMacs do, but hot.

Sounds like if you use your Mac to read a document in the morning, you can

cook your eggs on it.

There is a definable stagnant 'well' of hot air in the top of the internal space that is not easily replaced.

The hot air definitely needs to be drawn out.

I have long contemplated addition of active ventilation to my Mac.

I agree.

Based upon the discussion here I am now of the opinion that active ventilation (or a chimney) must be used as a general practice. it should only be operated on its own for short periods.

Thanks for your valuable input.

--David

 

[dbraverman88]

I'd have a look at the surge suppressor and see if there's anything you can do to quieten that down (maybe a quick clean and/or re-lube of the fan bearings/sleeve might work wonders).

Great idea. This will also go on my project list.

--David

 

[dbraverman88]

The decision for convection cooling was done mainly by fiat, not as the result of any careful engineering analysis.

Making excutive decisions is critical for the success of any organization. Hopefully they are only done after careful consideration of all of the available facts. But the reality is, production schedules often do not allow the luxury of careful research. Often a research cycle ends this way: the deadline has been reached before the completion of the research. The decision must be made on what information is available, complete or not.

Just my 2 cents.

--David

 

[dbraverman88]

Do some research on the Mac Chimney

Fantastic idea. Chimneys work well. On the project list it goes.

Thanks!

David

 

[MacJunky]

/me pats his Kensington system saver.

 

[tomlee59]

The decision for convection cooling was done mainly by fiat, not as the result of any careful engineering analysis.

Making excutive decisions is critical for the success of any organization. Hopefully they are only done after careful consideration of all of the available facts. But the reality is, production schedules often do not allow the luxury of careful research. Often a research cycle ends this way: the deadline has been reached before the completion of the research. The decision must be made on what information is available, complete or not.

You are talking in generalities, and then ascribing them to this specific instance; you are making the implicit assumption that this rational process was followed here. Let's look at the history, and judge for yourself: The engineers (mainly George Crow, chief designer of the analog board) knew that it ran too hot without a fan, so one was designed in. Jobs didn't like the noise, so the fan was taken out. He placed a premium on silence, and was willing to sacrifice longevity to achieve it; heat wasn't HIS problem. No deadline pressure forced a decision based on incomplete information. All involved knew that reliability would suffer. It is relevant in this context to note that, even as field reports of heat-related failures accumulated, the fan option was never exercised. From the 128's debut in 1984, to the retirement of the Plus in 1990, no fan was allowed in.

Fans crept into Mac designs after Jobs left. They were forced out again (of the imac) when Jobs returned, again to the detriment of longevity, and again over the objections of engineers.

So you see why I said that the design was by fiat. It was not due to any naiveté on the part of the designers. They knew precisely what would, and did, happen.

 

[SiliconValleyPirate]

I pulled a current off the pins on the external floppy drive port on my Plus and wired it up using a D-connector to 2 486-era heat sink fans that I wired on over the sloping vents either side of the handle. It works well enough - the one on the analogue board side really throws out a lot of heat that'd otherwise be wandering around inside. The vents on those babies are really poor, but i think they had to be like they because of the plastic they used to mould the case and the moulding technology being a bit more limiting in 1988. A little fan assistance helps no end.

 

[JDW]

I have a stock 512k (fanless) and a 512k with a fan that accompanied the internal 20MB GCC HyperDrive that was installed in it. The HyperDrive itself is pretty loud, so you can hardly hear the fan over the drive noise. But if the drive isn't spinning, you can definitely hear the fan. For that very reason (fan noise disturbs my mental health terribly), I swapped out the rather loud Elina stock fan in my SE/30 for a hardly audible Silenx 60mm fan. But if you choose other Silenx models, beware. I bought an 80x25mm Silenx and an 80x15mm Silenx to use in my G4 Cube. Both 80mm fans are either defective or Silenx simply ripped me off in that they are louder than the "loud" Elina fan used in my SE/30! But again, I can say that I absolutely love the 60mm Silenx I have in my SE/30, and if I were to put a fan inside my fanless 512, it would certainly be another one of those! The 60mm Silenx also draws a mere 50mA of power, so it won't tax your analog board.

The question at this stage is how to mount a fan in a 128/512 since, unlike the SE series, they don't have a ready-to-go fan slot waiting for a fan and screws. My HyperDrive machine uses velcro, of all things, to mount the small fan in the upper left back corner of the machine, shooting hot air out the slits in that part of the case. Even after all these years (since 1985) that tape has kept that spinning fan in place. So I guess if you can find the same quality of velcro tape, that would probably work just fine. But I would also think that mounting a fan in other ways could work just as well, even mounting the fan to blow air directly onto the analog board. Indeed, any air movement inside the Mac's housing would make it cooler than no air flow out all. But then, you should open such Macs up every year or two to vacuum out the dust bunnies sucked in by the fan. Your floppy drive may need cleaning more often too.

 

[dbraverman88]

The decision for convection cooling was done mainly by fiat, not as the result of any careful engineering analysis.

Making excutive decisions is critical for the success of any organization. Hopefully they are only done after careful consideration of all of the available facts. But the reality is, production schedules often do not allow the luxury of careful research. Often a research cycle ends this way: the deadline has been reached before the completion of the research. The decision must be made on what information is available, complete or not.

You are talking in generalities, and then ascribing them to this specific instance; you are making the implicit assumption that this rational process was followed here. Let's look at the history, and judge for yourself: The engineers (mainly George Crow, chief designer of the analog board) knew that it ran too hot without a fan, so one was designed in. Jobs didn't like the noise, so the fan was taken out. He placed a premium on silence, and was willing to sacrifice longevity to achieve it; heat wasn't HIS problem. No deadline pressure forced a decision based on incomplete information. All involved knew that reliability would suffer. It is relevant in this context to note that, even as field reports of heat-related failures accumulated, the fan option was never exercised. From the 128's debut in 1984, to the retirement of the Plus in 1990, no fan was allowed in.

Fans crept into Mac designs after Jobs left. They were forced out again (of the imac) when Jobs returned, again to the detriment of longevity, and again over the objections of engineers.

So you see why I said that the design was by fiat. It was not due to any naiveté on the part of the designers. They knew precisely what would, and did, happen.

Very interesting. It certainly appears that Mr. Jobs is a businessman who values aesthetics over sound advice.

--David

 

[tomlee59]

Jobs definitely values aesthetics above almost all else. And given his brilliant successes, it's hard to argue with what he's done. That said, a few of his decisions have caused engineers and consumers more than a bit of grief. Perfectly round mice, anyone? Or dual-arm floppy drives? Or...