Thread
Is using an external fan needed with a Mac Plus?
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
--David
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
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
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
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
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!
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!
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.
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
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
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.
Thanks for the suggestion. This will be added to my project list.
--David
Sounds like if you use your Mac to read a document in the morning, you can
cook your eggs on it.
The hot air definitely needs to be drawn out.
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
Great idea. This will also go on my project list.
--David
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
Fantastic idea. Chimneys work well. On the project list it goes.
Thanks!
David
/me pats his Kensington system saver.
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.
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.
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.
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.
Very interesting. It certainly appears that Mr. Jobs is a businessman who values aesthetics over sound advice.
--David
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...
equill, are you saying your 512Ke does not have the same rear bucket the 128K, 512K & Plus have? i.e. vents on the top left & right side of the handle and vents in the top rear chamfered corners? Traditionally the fans added to a 128K-Plus go in the corner opposite the analogue board. The bucket you are describing sounds more like a Classic with vents only under the handle.
Tom, you neglected to mention the original anti-fan heat debacle: the Apple III, which overheated to the degree that the chips expanded and popped out of the logicboard and Apple actually suggested consumers drop the computer on the floor to re-seat them. I guess Jobs figured if there were no sockets in the 128K, they couldn't expand and pop out from the heat, so no worries.
Verily that is what I wrote, but it is not the case (pun accidental). The chamfered corners have horizontal slots. The top side edges are indeed provided with (seemingly) pressed-in louvred panels, rather than the same kind of open slots. This press-in could have been Apple engineers' desperate late response to the fiat against an internal fan, as raised by tomlee59.
When I first held the bucket to the light some days ago the louvres appeared simply to be translucent plastic grooves. However, your question prompted me to go back to where I have been handling the bucket intermittently for several days, and to look with an angled light source. Sure 'nuff, there are slotted openings at the rear edges of what I had wrongly taken to be mere incuse grooves. The bucket defiantly displays the Apple press-in logo. and the legend 'Macintosh 512K', as well as the moulded-in P/N 810-0374- and stamped-on 630-5139-A.
With the acute vision that hindsight engenders, the intended internal fan's position could be thought to be reflected in the moulding of the bucket, but in a position closely analogous to that of the SE/30's fan. The signatures in that part of the bucket would have been casualties of the fan's positioning, as the signature of Steven Jobs near the centre is already (and perhaps, ironically).
de
Whew! For a minute there I thought you had some kind of late model variant to the 512Ke!
As Tom Lee correctly points out, Jobs always intended the Mac to be fan-free ... it is the engineers who attempted to defy him with expandable logic-boards boards and fans ...
As for the top vents, I don't believe it was ever a last minute decision as Jobs always intended the Macintosh to be convection cooled and fan-less. I would need to double check, but I'm pretty sure that's what I recall from various sources. Actually a lot of thought went into the deign by Apple engineers to make Job's vision possible. The top vents are one such example. Jerry Manock, responsible for the overall industrial design language at Apple up to that point, as well as specifically the rear bucket, took great pains to come up with a design which would both adequately vent the heat (notice I did not say optimally), but also keep small children (present in the households of the target consumer) from sticking things into the top of the Mac which could easily come in contact with lethal electronics. If a child stuck a paperclip into the bottom grille, at worst it would short your logicboard. But nobody would die. All this is explained in Kunkle's Apple Design and other sources. My guess for the vent inserts, versus moulded directly into case is that it was too complicated a mould for the technology of the day to do in one piece ... it is also the only aspect of the Macintosh that doesn't conform to Jobs' other mandate that the Macintosh be as close to a single moulded unit as possible with no seams. Obviously he compromised his vision for safety. You'll note the vents in the chamfered corners are equally resistant to inserting something, but were obviously accommodated by the mould.
I had forgotten that picture. Excellent example. The Dana has that auto-on thermostat too, a nice touch back in the day. Larry Pina shows the exact procedure and a similar picture as well for just the fan. If you don't have one already, Macintosh Repair and Upgrade Secrets is a MUST have for the Vintage Mac user and fairly easy to come by these days.
FYI, adding a fan requires adjusting the voltages to accommodate the added power requirements.
ALSO: The SE sold an optional floppy drive plastic shield back-in-the day as an "option" to reduce the amount of dust sucked through the floppy drive opening and eventually clogging the works. You would be well advised to create a similar enclosure around your Plus floppy drive to avoid future problems there, especially considering the venerability of these early drives to mechanical failure. Hard to believe it was an option based on the grotesque conditions I have found many of these drives from SEs which were never cleaned.
I wonder - some kind of homebrew heatpipe soldered to an external heatsink out the back of the case for silent cooling?
Positive fan ventilation, so as to reverse the direction through the FDD? Maybe even improve the airflow past the power/sweep board?
de
de
Mac128, since you mentioned the required analog board voltage adjustment after adding a fan, I thought it best to mention one more thing. The fan in my HyperDrive 512 also passes it's power wires through a filter, as shown in this photo. EMI filters and chokes are technically not required, but if you see "snow" on your CRT after adding a fan, you will need to add such filters to clean it up. As a result of having these filters (which are external and separate from the secondary PSU that accompanies the HyperDrive), there is no on screen noise when the Hyperdrive and cooling fan are running. The screen is just as clean as my other Mac512 which is stock (no fan, no hard drive).
It's worth a try ... however, it does not sound as efficient. The entire configuration was designed to maximize convection, i.e. the hottest components located near the top to draw cool air up. Forcing air down through the Mac would actually send hot air down into the case.
As for the reverse airflow through the FDD, that would not eliminate dust build-up. In fact more dust might be drawn in from the top than gets sucked in from the bottom. Either way, without a dust shield, the FDD is going to get filled up with dust bunnies no matter which way the air flows. Apple finally added a slot cover to the Superdrive around the Colour Classic era to prevent dust from getting sucked-in through the drive. These drives were almost fully enclosed as well.
'Positive' in this connection may have meant something different to you from what I intended, which was maintenance of a positive static pressure within the case, as opposed to the negative static pressure during air extraction by an exhaust fan. I envisaged that air be blown into the case by the fan, and therefore that it follow (more-or-less) the path intended for convected air over the power/sweep board and out through the top vents. How much dust ingress there might be would depend on the point of air input, and the presence or absence of a filter at the input. Having air flow through the FDD from heads to insertion slot could well be an improvement over the reverse direction of airflow, although that is at much slower flowrates during convective cooling.
de
de
equill, no i got what you meant. picturing the intake fan in the same location as for exhaust, you will be forcing hot air from the top of the case down through the case, regardless of how cool the outside air is, you are working against physics to push the hot air generated at the top of the case down through the bottom. Since dust generally is stirred up in the air and settles downward, pulling air through the top will also pull in more dust. Therefore, I doubt the flow direction of dust-infused air will matter much.
Now if I follow what you are saying now, I take it you mean to install the intake fan near the bottom vents. That is certainly preferable, but somewhat challenging. I suppose the fan could be mounted parallel to the metal chassis over the large opening behind the FDD above the logibcboard. This is similar to the Classic/II fan with the air scoop drawing air in from beneath the case. I would still seal up the back of the FDD to prevent airflow through the bulk of the drive as well as the other openings in the chassis deck to maximize the draw of cool air through the bottom vents and minimize hot air recirculation. But trust me, you'll still be drawing air in through the bottom vents and my 512Ke that had used a Kensington System Saver had a thick carpet of dust coating the logicboard. That more or less confirms an equal amount of dust is likely to cover the FDD, regardless of which direction the air flows.
None of this is particularly destructive either. As long as we're making changes, I had always thought mounting the speaker on the analogue board face down on the chassis would improve the speaker sound by sending it unobstructed through the bottom vents. With the addition of a fan, it could be mounted face up through the front top grille opposite the analogue board.
Now if I follow what you are saying now, I take it you mean to install the intake fan near the bottom vents. That is certainly preferable, but somewhat challenging. I suppose the fan could be mounted parallel to the metal chassis over the large opening behind the FDD above the logibcboard. This is similar to the Classic/II fan with the air scoop drawing air in from beneath the case. I would still seal up the back of the FDD to prevent airflow through the bulk of the drive as well as the other openings in the chassis deck to maximize the draw of cool air through the bottom vents and minimize hot air recirculation. But trust me, you'll still be drawing air in through the bottom vents and my 512Ke that had used a Kensington System Saver had a thick carpet of dust coating the logicboard. That more or less confirms an equal amount of dust is likely to cover the FDD, regardless of which direction the air flows.
None of this is particularly destructive either. As long as we're making changes, I had always thought mounting the speaker on the analogue board face down on the chassis would improve the speaker sound by sending it unobstructed through the bottom vents. With the addition of a fan, it could be mounted face up through the front top grille opposite the analogue board.