Macintosh SE or SE/30 Fan Bracket

[Trash80toG4]

And Steve Jobs hated fans, including air conditioning. He believed that the airflow should be natural, not forced.

However, he didn't put much stock in vents for his precious Mac's bucket design. He was badly mistaken in his assumption that deodorant was unnecessary as well.

IMO your quest for thermal disbursement for the 68030 is a solution is a search of a problem. Can't think of a single case where engineers found need for it.

 

[Trash80toG4]

Back on topic: @alxlab have you looked at the round to rectangular transition at all? Thoughts?

 

[retr01]

However, he didn't put much stock in vents for his precious Mac's bucket design. He was badly mistaken in his assumption that deodorant was unnecessary as well.

Yeah, that's Steve Jobs. He may have dismissed the notion that the computer is an artificial extension of ourselves and wanted to make it a natural extension of ourselves. It's a parody!

Rod Holt and other engineers tried to drill through Jobs' head that fans are needed to keep the Macs within normal operational parameters. Steve boycotted deodorants because they clog up the body's natural cooling functions, yet he advocated fanless Macs. Weird, huh? His trip to India may have messed up his perceptions.

Did you know that Apple Park (the ring building) lacked fans and air conditioning? I wonder if that quietly changed after Jobs' passing?

IMO your quest for thermal correction for the 68030 is a solution is a search of a problem. Can't think of a single case where engineers found a need for it.

The Motorola 68030 does not need thermal correction at lower frequencies or typical operational factors. However, the higher frequencies raise concerns because of untypical user inputs. For example, an intensive computational and processing program, overclocking the frequencies, or warmer surrounding ambient temperature. Motorola (NXP) recommends thermal correction such as heat sinks in those situations. That can help maintain the CPU to control premature wearing out by entropy.

Notwithstanding, in almost all cases, the 68030 does not need thermal correction. Yet, some people prefer that. I am not sure if this concern is common in the Macintosh community, but it seems to be in the Amiga community.


Cheers!

 

[alxlab]

Back on topic: @alxlab have you looked at the round to rectangular transition at all? Thoughts?

Actually yes! A couple of days ago I fooled around with the 3d design software I use (123D Design) and found the loft feature. It was a little tricky since the fan bracket is asymmetrical. The result is this:

So it would have the same transition that a duct boot would have. Think it would still be printable on a FDM printer with no supports but I haven't tried it yet.

 

[retr01]

Before printing one, I will wait for @alxlab to fine-tune this updated fan bracket design.

Hey @alxlab, my Noctua fan would be between those two pieces, right?

 

[Trash80toG4]

So it would have the same transition that a duct boot would have. Think it would still be printable on a FDM printer with no supports but I haven't tried it yet.

Very, very cool! That should help a lot in moving more air more easily.

It might not feel like that to the touch if compared to the first version with machines side by side do to pressure reduction in the boot's more efficient transition? But that will likely also help by reducing turbulence created by the grill? Smoke testing in a pair of clear cases side by side ought to tell the story? Videos made using a single case could work as well?

Clear plexi boxes hooked up to the same incense smoke production chamber would be an interesting setup for demonstrating any differenct in a more controlled environment. I wouldn't expect to see a huge difference, but I'd think the incremental benefit in the transition's efficiency should be detectable by eye?

Fabulous work.

 

[-SE40-]

Hi all, this talking/creating ducts and new fans got me wondering…..
I like the idea of better cooling and making these machines more silent.
Personally I suspect that cooling the tube is more usefull than the CPU….but guessing does not compute.

So just to get an idea what actual temps we are talking about, I will try measuring the ClassicII CPU under different loads, begin temp 17C. (Edit: After 4 hours idle and light use the 68030 reached 47C)

What and where can I find a simple program to put some load on the processor?

Maybe if you all do the same, we can come to a better understanding of temps behaviour this way of all the small(?) Mac models?

 

[retr01]

What and where can I find a simple program to put some load on the processor?

MacBench 3.0, Apple Personal Diagnostics (APD), and Norton System Info 3.5.3 are a few system bench tests with CPU tests. Those programs can be found on the Macintosh Garden site.

Cheers!

 

[retr01]

Another one is Apple’s MacTest suite:

Apple MacTest Pro (680x0) CD-ROM 691-0590-E 1996 : Apple : Free Download, Borrow, and Streaming : Internet Archive

Apple MacTest Pro (680x0) CD-ROM 691-0590-E 1996

archive.org

 

[-SE40-]

Niceone….i want that later for my 630.
But it should also be able to run from a floppy on a
Lite 512 mac for later temps comparison?
Only a bit of constant CPU load is needed.
Is there not a standard system 6-7 builtIn program what can do that?

 

[Trash80toG4]

Personally I suspect that cooling the tube is more usefull than the CPU….but guessing does not compute.

Cooling the flyback is probably the most important thing in Compacts. Note that they're always near the cooling vents/fan. PSU components would likely be next. CPU is waaaay down the list compared to the bumple thingies on the A/B I'd think. Some hot ones on the Plus and +Minus A/B boards are placed lower and to the front of the A/B so they draw air from the vents and across the LB to induce convection cooling.

 

[retr01]

@Trash80toG4 is correct. The flyback is the most significant heat source in compact Macs with CRTs. Yet, if CRT is replaced with the LCD, the most prominent heat source would probably be the PSU more than the CPU. However, it depends on what is inside after modifications. It's a good idea to test CPU temperature in a modified environment.

 

[-SE40-]

Cooling the flyback is probably the most important thing……

Why did they not put fans in crt televisions then? Was that any different?

 

[retr01]

I imagine the compact Macs are more cramped and have more things that heat up internally. Televisions generally have more space inside for airflow that works sufficiently for convection cooling.

Cheers,

 

[-SE40-]

Well, I have had this small portable -maybe 10” TV - for many years, helping heating up my room….not that much different from a compact Mac.
No fan or whatsoever.

 

[YMK]

Why did they not put fans in crt televisions then? Was that any different?

TV flybacks are typically near the bottom of the case where air is coolest. Most TVs have plenty of vents for passive cooling.

Flybacks on the SE and later are up high in the case, above the exhaust, where hot air is trapped.

Apple should have kept the Plus's vents. The Classic's cooling setup is decent, but the SE(/30)'s is poor.

 

[-SE40-]

Thanks!
This seems like a good explanation to me.

Indeed strange they left the Plus vents.
Guess for the cleaner design….

 

[Trash80toG4]

Not all that uncommon for the Plus' vents to melt above the flyback.

I think SE cooling was probably fine until the went to the muffin fan to reduce noise. The original Cross Flow Fan was more efficient. That's what you'll find in all kinds of things, Laser Printers, copiers and the like. It is not a squirrel cage fan! Squirrel cages are centrifugal blowers, very different.

It looks to me like they did a crap design to fit either type of setup and it didn't work all that well with either. Again, Apple!

 

[-SE40-]

Now looking at a measured 47C on the 68030, fully enclosed CLII idle, light use….the 70C when on load (google) seems viable.
Flybacks+ other heatsources-Plastic ABS melting….say from 150C,
cooling is no option, its a must!

 

[Trash80toG4]

cooling is no option, its a must!

None of the brilliant, outside the boxers at Apple could get that through one particularly thick skull with blinders attached. Hyperfocus on design to the detriment of function is a major failing in a project director. Reality distortion is a multidimensional field, deleterious thought well field affects objects on both sides of the nexus. While he may have been uninvolved (or gone from?) Apple at the time of SE development, design over function culture was firmly in place much to the detriment of product development. Once again, Apple.

Crossflow is the perfect choice for the top corner cooling requirements of the SE/SE/30 bucket.
Design charicteristics: https://catalog.orientalmotor.com/viewitems/mf-series-ac-cross-flow-fans/150mm-ac-cross-flow-fans#

Note the intake overlaps and isolates that one slot in the flyback heat shield, pulling air across the entire bottom slats of the cooling section. Note the four slots in the top fan housing that impart centrifugal (squirrel cage) blower effects not commonly seen in cross flow design enclosures. They pull airflow straight down from the hot corner above across the vertical rear and top of the heat shield/spreader/radiator surfaces.

Metal side panel helps to direct air from the high pressure fan's exit to the wider, pressure reducing grill boot molded into the back of the SE bucket. Such reduces noise, but apparently not enough for the transition from silent convection (preferably with System Saver) in the Plus to proper cooling in the SE.

Switching from tangential cross flow fan to axial muffin fan retrofit was all kinds of counterproductive I'll posit.

Best case solution would be finding an A/C cross flow fan in a modern, refined, quieter design bodged to the switched A/C feed. Such would reduce stress on the A/B, eliminating power requirements on the 5V rail while cooling far more efficiently, right where it counts.


< /rudimentary understanding of fluid dynamics and package design for computers, ME middle little bro's forte >

edit: placement of that big wide cap in that space appears to smooth the right angle transition of airflow from top of cooling radiator/heat shield?

moar pics: ImageConverter playtime in new worktop Lombard/OS9 and hardware/LCD screen alignment fun = beans

Far wider angle pull from PSU than muffin fan. Where are hottest PSU Components located, toward rear or front?

Additional cubic available for larger pass thru fan?
--- 63mm housing exit
--- 43mm impeller blades
--- 67mm grill height
__________________________________________________________

Optimal solution for crazy SE/SE/30 expansion configurations would likely be a reloaded, upgraded component A/B per @apm's retina display hack. Such would open up myriad possibilities such as moving the flyback cage forward/down thru optimized printed ductwork on both sides pulling airflow into and out the grill smoothly thru an upgraded Noctua axial fan.

Bonus points available for new sheet metal ductwork replacing stock heat shield/spreader/radiator to eliminate pressure reduction/turbulence induced by backside of OEM unit dating back to the minimally expandable SE's A/B.


@alxlab I hope this isn't too tangential for topic, I did (finally) swing it back onto your printed component track.

Thanks to link to this JDW thread from 2.5 years ago . . .

Macintosh SE Squirrel Cage Fan to 60mm Boxer Fan Upgrades

I've been working on a new video focused on SE and SE/30 fan upgrades over the last month and a half. I don't have any machines with the old squirrel cage fan, but I am aware many SE owners are. I want to add info in my video for those folks. I've searched this forum for "squirrel cage" and...

68kmla.org

. . . I've finally run down Wikipedia articles that explain the differences between the three types of fans used in computers:

Industrial fan - Wikipedia

en.wikipedia.org

Fan (machine) - Wikipedia

en.wikipedia.org

Computer fan - Wikipedia

en.wikipedia.org

Found some great pics. One is a patent drawing for cross-flow fan that lends itself perfectly to an overlay of scale drawing in AI showing Apple's implementation of cooling in the SE. The other shows the wide angle intake a bit more clearly.

@-SE40- has been experimenting with temperature sampling and I think we've come up with a solution for a definitive test of the efficiency of the four configurations available at present:

1 - original cross-flow fan design of the SE
2 - retrofit of tube axial fan to existing case config by simple rectangular sheet metal duct to later SE and SE/30
3 - upgrade of sheet metal duct to improved, printed cylindrical duct developed by @alxlab
4 - his circular to rectangular boot duct refinement of first design

Temperature sensor would be affixed to outside of the SE's slot free, solid surface flyback enclosure. That way it would be a constant in the four test cases. I'm thinking that in that position sampling will be done in a static airflow state, unaffected by airflow geometry?

All four configurations would be tested in the same SE so that would be a constant. Has anyone got an SE fitted with Apple's conversion kit. That would make for a fifth test configuration.

@JDW @Scott Baret mentioned the Apple fan conversion kit for the SE in your MLA thread. Have you got an example? If so, you have an original, horizontal neck board "squirrel cage" or access to one, no? If you don't have everything required, I'm sure we can manage to get everything needed for a definitive test routine into your lab? If we can work out details, I think you may have the makings for an interesting video here?

Dunno anything at all about sampling for sound effects of the test configurations. Decibel output count would be just as interesting I think?

Electrical interference from the original design/horizontal neck board was mentioned by Scott as being the reason for the changeover in fan types, not complaints about noise as would be received wisdom (disinformation?) on this subject.

morning musing of the day: thinking a test enclosure isolating intake and exhaust airflow would be very cool here. Using a light weight/low mass fan of some type at the exit might yield interesting results on a meter measuring DC voltage output? Can't think of any other way offhand to test airflow/velocity of the setups?


@Kai Robinson would it be possible to move this tangent to a dedicated hardware topic now? I'd love to get feedback on this insanity. I'll be fleshing out this WIP IP with details and pics of what I've found today. Questions and suggestions from the gang would help me set up illustrations when I can play with this stuff in AI.