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Fan replacement for a Mac SE/30

superjer2000

Well-known member
I am always surprised more people don’t mention these Nanoxia fans:  http://nanoxia-world.com/en/products/fans/deep-silence/240/deep-silence-60-mm-2000-u/min?c=50

2000 RPM, 15.8 CFM, 12.1 dBA

So, more airflow and less noise than the Noctua at the 2400 RPM setting (allegedly).  I’ve been running one in my maxed-out SE/30 for about 18 months now and it seems to keep things nice and cool.  Though I always wonder if it’s really doing the job ...

@superjer2000 did you ever build that temperature controller?
I didn't. I put the SE/30 back up on the shelf and haven't gotten back to it.  It is still on the project list though. 

 

Nathanplus

Well-known member
They used the same sized box fans in the powersupply of the powermac g4 quick silvers. You can probably pick one of those up for cheap or see if a family member has one.

 

Crutch

Well-known member
I didn't. I put the SE/30 back up on the shelf and haven't gotten back to it.  It is still on the project list though. 
I’m experimenting with PWM fan control for my SE/30.  Does anyone have any ideas as to what the temperature operating tolerances are for the flyback etc.?  In other words — at what point should I have my fan controller max out the fan speed?  (Ideally I’d install a fan that’s powerful but maybe noisy at top speed, but could run it at slower speeds most of the time.)

Right now I’m playing around with this little fan controller, $5 on Amazon:  https://www.amazon.com/gp/product/B077SLWWXL/  Takes a minute to figure out the settings (the “UI” is one button and three LEDs) but seems to work great.

 
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jessenator

Well-known member
Maybe I'm sleep-deprived, so check me if I'm off my nut.

Since the intake on these is on the bottom, there's this up and back airflow (blue) which would create kind of a low pressure situation (yellow) right up at the top (where the flyback is). Since the SE there were no more vent louvers at the top of the case, so the air wouldn't flow that direction, right through the flyback cage as might be the best goal. So I'm curious if a cowling, albeit a bit choked, might serve the flyback more by forcing the air to flow through the cage itself? I mean, obviously, it seems like placing the fan higher up, directly in the path of the flyback could have served airflow better (red), but spilled milk and all that.

gtBYJ6I.png.d0a0860d328a315a93c0428fbef12332.png


It would be a wonky fit at best, having to make space for board connectors. Way out of the realm of feasibility would be a modified cage for the flyback. anyway enough rambling…

 

joshc

Well-known member
So, what's the verdict then, what is the best fan, given consideration of appropriate airflow but 'not too loud' ? I would personally prefer something that's a little loud but gives adequate airflow rather than something really quiet that isn't up to the job.

Is there an argument for leaving the original Elina fan in there at all, or is just not up to the job to begin with?

 

Bolle

Well-known member
I had one of my SE/30s out that actually has a bucket on and was surprised about the airflow that's coming out of the back with the stock fan.

I thought about replacing the fans in my machines mostly because they are all stuffed with cards and upgrades to the top but I am not sure if that's really necessary.

My machines all run real hard drives anyways so noise is not really a concern and I'd rather have a louder fan that moves some more air.

 

GeekDot

Well-known member
Hi - Just to throw in my 2 Euro cents here:

All I've read in this thread is RPM, decibel and CFM... but you're totally missing one important number: Static pressure (Measured in 'mm/H2O' or sometimes in 'Pa')

Especially systems been cooled by sucking air through the whole box having obstacles (i.e. power-supply, big objects like humongous caps etc.) in the way of the draft it's all about how much 'ooomp' poor little fan can deliver.

It's a bit like horsepower vs. torque. 

Nocturas and the likes are the Ferraris in the world of fans - lots of HP (CFM) but comparably low on newton meters (mm/H2O). 

And then there are the tractors. Not the fastest and nicest ones... but boy do they pull. 

My '30 has a  Panaflo FBK06-12L - can't find a datasheet for it, but its 40mm brother has a static pressure of 2.5 mm/H20 - I dare betting the 60mm Panaflo is at least pulling 3 mm/H2O.

The recommended Noctura is at 2.18 mm/H2O

The recommended Delta Electronics AFB0612EH-ABF00 is at a absurdly poor 0.544 (@38.4 CFM) 8-o

So if there's not enough draft, after some hours your PSU might get cooled ok'ish, the flyback's already sweating and the the harddrive is about to be grilled by that Turbo040 down there... :sadmac:

So in a one sentence: "Don't look at CFM. It's mm/H2O that matters!" (At least in the case of compact Macs... pun intended ;-)  )

I've written a bit more detail in this post over here.

 

Trash80toHP_Mini

NIGHT STALKER
Thank you, hadn't thought of it that way. Dust collection systems are designed with static pressure losses in the ducting being of paramount importance. Substitute hot air molecules for dust and I think it very roughly illustrates your point.

Using pressure monitoring to maintain dust collection system performance.

SP-resistance-cfm-graph.JPG

A dust collection system's often designed with fan size (blower capacity) as the product of the multiple variable equation. For cooling a computer case, inlets, resistance and "fan size" would be constants, leaving power application as the product of the equation. Interestingly, that article lists "Smoke Test" as the determinant for proper hood design efficiency measurement, AKA bucket and vents. This seems to go  pretty far in explaining clear cases produced for the casedesign process. For dust collection you'd be looking at smoke heading into the system as in the case of the cooling vents and inside the clear case the smoke test would also indicate airflow distribution across critical components so:

Pretty sure the design of the sheet metal surrounding the flyback was very carefully calculated and tested.

Not awake enough to make an automotive torque analogy, but WAGing the same principles might apply? Mechanics, fluid dynamics and thermodynamics be power application horses of another colors? :blink:

 

jessenator

Well-known member
I racked my brain over this since March and didn't come up with anything that would be even marginally feasible or worthwhile—i.e. a cowling of sorts to divert egress airflow out around the FBT). I did however come up with what I think is a decent alternative:

I found myself with an extra Noctua 40x40x10mm fan. And while I had my SE/30 open for swapping out CRTs, I worried about the condition of the FBT (flyback transformer) and how it would respond to driving other CRTs. but that point might be moot. At any rate, I decided to do a rather unsophisticated surface temperature test on the FBT (with the case open). After a decent warm up time I was reading between 94–96º F (34–36º C)—my IR thermometer is reasonably accurate, but there's certainly a margin for error. I decided to just plug in the 40mm fan with the unused molex power connector (thanks, SCSI2SD) in my case (the permanent case fan is hard-wired) and do the same test again—setting the fan just on the top of the FBT cage where there were grille holes.

I measured the temperature again after warm up and there was a 10º F (~5.5º C) difference on the surface reading at 84–86º F (28.88–30º C). A thermocouple would be a sure-fire, but I think that sort of a temperature differential more than justifies the price of a small fan. I opted to place mine, post-case-closure, with the rubber shock-mount pieces included to the inside of the cage, toward the back (the only place it would fit) blowing toward the FBT. There's just enough gap in the cage grille to fit the fan on all 4 mount holes, should you desire.

I think it's a fair compromise to my pipe dream, and thought I'd share it.

 
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