While I seem to be on a posting binge today…

After indibil’s comment that his PSU was like the one that Jacques shows, I noticed that Jacques’ sub board (“Fan control board”?) looked amazingly like mine. And while the bottom of Jacques’ main board seemed a bit different, his noted locations of the capacitors on his main board were very similar.

D’oh! Same API number and same Apple P/N number.



So, compared some other AcBel’s noted in this thread and came up with the following.

AcBel,  API1PC12. APPLE P/N:  614-0157     aBc         QS xxx

AcBel,  AP10PC24. APPLE P/N:  614-0146    gert79     QS 933

AcBel,  API1PC12.  APPLE P/N:  614-0157    ovalking  QS 800

AcBel,  API0PC24.  APPLE P/N:  xxx-xxxx     ovalking   QS 933

AcBel,  API1xxxxx. APPLE P/N:  614-0157    Jacques    QS xxx

AcBel,  API1xxxxx. APPLE P/N:  614-0157     indibil      QS 800

Would like internal images of gert79 and ovalking’s QS 933’s.
[AP10PC24 or API0PC24.]

Here’s that House of Moth link:
https://thehouseofmoth.com/further-tweaking-the-cooling-part-1/

And an image “borrowed”’ from there as well.


House of Moth refers to the heatsink on the far right as the “metal heatsink” or “metal foil” and (perhaps like GaryN) I have always refered to them as “stainless”. Now whether or not the thin fins are chrome-plated aluminum or stainless steel, it seems that this heatsink ranks 2nd place effective for heat dispersion of the three shown above… with the copper heatsink being the best. (And there are also other variants of the aluminum (middle one) made specifically to accomodate different MDD processors.) Perhaps why indibil’s aluminum heatsink did not “seat” adequately?

A deep scratch test and a clip test of the “metal - finned” heatsink fins here revealed no visible underlying core of aluminum AND no magnet would stick (typical of both aluminum and some stainless steel). If I had to bet, I’d wager that these fins are stainless steel affixed to the thicker aluminum base. And especially after I have noticed rust on some of these fins in the past. Maybe chrome-plated aluminum also rusts?

                           

Also, see reddragon’s MacRumors posted pics of various different MDD aluminum heatsinks.
https://forums.macrumors.com/threads/mdd-heatsink-differences.2223970/?post=29952709#post-29952709

So, performance wise by the numbers, the copper heat sink still takes it home, the metal heat sink comes in second and the aluminum heat sink comes in last. Common knowledge is that the metal heat sink sucks, is useless, should be avoided etc. but these temperature readings show otherwise. What does make the metal heat sink a poor choice is the system instability it somehow causes. - House of Moth

Also from HoM:
Now keep in mind I am using graphite thermal pads which outperform Arctic Silver and even Thermal Grizzly Kryonaut by a wide margin, so that helps keep my temperatures down as well but the copper heat sink seems to be the way to go on any CPU.

Yes, heatsinks on my mind here today.

Wow! Have you tried it out and seen any difference in temperature compared to the stock heatsink?

No, not yet. Next on my list after recovery from current sinus ailment.
(From inhaling copper dust?)

This dummy didn’t wear a mask or respirator. Of course will do so with the next one.

Maybe call it an "iSink"… after indibil’s original approach?

It isn’t pretty (yet) but the first “replicant” here is finally complete.


                     Could use a bit of cleaning (copper dust particles, etc.) and some emery cloth smoothing of the rough fin edges.



Used a metal hack saw blade to cut the 50 x 50mm standard size down to 40 x 50mm and then a palm sander to smooth the rough cut edges. indibil used a 4” grinder with abrasive blade to remove 10mm - but I didn’t trust myself to go that route. Even tested a very small mini table saw and a mini chop saw… but they were too under powered for the task (so much so that the hack saw blade seemed better for a more controlled cut between the fins.. For the next one - may try a metal jig saw (or sawzall) blade clamped and held with vice grips to cut that 10mm excess off (again, by hand). Smaller and more teeth than shown here.



You may note the black dots on the face of the middle one in the second image above. Those are the projected locations for holes. I even created a paper template by scanning an actual G4 mini heatsink @1:1 for this approach but finally settled on a variant of indibil’s mating of the old heatsink, plus the new one (clamped in a vise) and then drilled.



Also in the second picture above… red dots denote one fin that was later removed, which brought this total fin count to 19. Unknown whether fewer fins will effect overall cooling but that’s a test to be done soon. (indibil’s copper heatsink has 20 fins.)

Also, the green outlined area (also 2nd image, left side) denotes the thicker base of the copper heatsink compared to the lesser thickness of the original stock heatsink. Thought might need to countersink the holes on the copper to facilitate use of the original “spring-pins” length but indibil said unnecessary and that the original “spring pins” worked well even with the slightly greater thickness of the new heatsink’s copper base.

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Trimming the fins. Where the real fun is!

Not really. Struggled and fretted over this more than anything and still have not arrived at a comfortable, set approach. I’ve enough finned copper stock here to make three more iSinks - so maybe by the last one I’ll have a better approach? For this first one, you might see where I drilled down through the copper to help locate the area where the spring-pins would enter the base in relation to the fins. This helped to guide how far back the fins would need to be trimmed. Then using very small metal snips, the fins were cut back as far as possible AND then used a Dremel tool with an abrasive bit to grind the fins back further. Also tried the Dremel with a circular abrasive disk to cut the fins, but definitely need more practice with that. Perhaps a combination of all the above would make it all easier / better?

CNC machine.
Yeah, I know.

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From here, the next step for me will be to test what effect the copper heatsink might have on air exhaust temperatures compared to an original heatsink in a stock 1.5 GHz G4 Mac mini (if any at all). I think the temps may be hotter but those I have asked seem to think that: (1). The temps will be the same, or (2). Fan speeds will decrease.

AND all of this in prep for possibly overclocking a G4 mini to 2 GHz. My thanks to indibil and to sailorMH for their efforts in relation to the entire subject of overclocking the G4 minis. Might have to eventually send one of these finished heatsinks over to the Czechia (sailorMH).

For more in-depth, G4 mini overclocking info (warm up your Google website translator):

indibil…
https://rosysumenteinquieta.blogspot.com/
https://rosysumenteinquieta.blogspot.com/2023/12/mac-mini-g4-192ghz-con-disipador-de.html

sailorMH…
https://www.amigaportal.cz/node/156189

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"fastest" flash, and using a pencil to overclock - MacRumors

Other info on overclocking the G4 Mac mini? There’s a thread over on MacRumors where ervus (in 2020) first mentions overclocking a mini to 2 GHz w/o a 7448 - but it still overheated. Read all (currently) 8 pages of that thread. (Perhaps this is what Jubadub previously referenced?) And although indibil’s resistor tweaks and current adjustments might be the final word in stable overclocking the G4 Mac minis to date.

Begin with ervus:
https://forums.macrumors.com/threads/fastest-flash-and-using-a-pencil-to-overclock.1973903/page-2?post=29415588#post-29415588

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Random errata:

Drill bit size = 3.0mm

Harbor Freight (in the U.S.) sells a small set of metric bits for less than $5.00!
HSS Micro Drill Bit Set 3 / SKU 61526 / $2.99. (30 assorted small bits)


                                                                                                                                                               Hole template with fin trim-back info

You can either trim back 1/4” (6.35mm) of the fins in the front and back locations
(like indibil has done) OR… take a full 5/8” (15.875mm) from the back location.
See first image here at the very top.

Sourced the heatsink blanks, 50 x 50 x 20mm and the 100 x 50 x 20mm from:
YOLOWIN / AliExpress. 100 x 50 x 20mm can yield two for a few dollars more.

https://www.aliexpress.us/item/3256804076300199.html  50x50x20

https://www.aliexpress.us/item/3256804078907505.html  100x50x20

AND - used slow speed on the drill press as copper is very soft metal.

AND - AND… thanks to Philgood for first mentioning indibil!

[...] perhaps some installed 7447s have more stability at 2GHz than others, perhaps mine do not, others perhaps do.

Correct. The probable reason yours and @GaryN's didn't work, and the probable reason @Knezzen's worked, is a matter of what we call Silicon Lottery. There is something else called Processor Binning. I found one of the MacRumors PPC threads I go on and on about those, and the custom 7448 dual 2.0GHz upgrades. To understand processor binning, and why it matters, refer to this comment, and about silicon lottery (plus a lot else), check this comment instead.

In short, @Knezzen won the lottery! But all of you may acquire and try more 7447 processors with the highest binning, until you win that same lottery. From experience, I will say your chances are very good with very few tries. Also keep in mind there are 3 main different MDD coolers (go for copper if you can, else the pure aluminium one. The other one reportedly freezes MDDs during stress, according to House of Moth, whose links describing this I no longer have), and they matter and differ a lot, but if you can LCS it with a silver base, that would be best, but not at all needed. I would also recommend, again, going for 7448 processors (if you find them) with the highest binning, and getting those instead, because the Sonnet MDX daughtercard can be used without requiring an interposer board, unlike with the stock MDD daughtercards. The 7448s also run cooler.

Anyway, be happy that you guys even have access to an MDD, let alone MDX daughtercards! I couldn't find the latter even when in Germany for 2 whole years of stalking eBay and the like. If you can find an MDX card, you can find A TON of 7448s! I know I did. Keep looking!