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[fergycool]

Original content of this post moved to:
https://macos9lives.com/smforum/index.php?topic=6875.msg58084#msg58084

Until this post can eventually be deleted, and then properly beginning this topic with the post below from Wozniattack (which should be the first post under this topic).

Apologies for any resultant confusion.

[Wozniattack]

Hi folks,

I recently repasted my mini following this, but wanted to ask about the thermal pad on the bottom chassis for the graphics chipset. Why does no one ever seem to replace it? Mine seems a little gunky looking from two decades, and the service manual states it needs to be replaced if the logic board was removed. Does anyone happen to know the thickness. Can’t find that anywhere even looking up the part number.

I’d like to give the mini even more life, and I use it to play some classic games also.

It looks about 0.5mm, but in the service manual the photo appears 1mm nearly.

[aBc]

Sorry.

I’m 600 miles from my calipers @ present but I do just happen to have one of those pads stuck to the top of a bottle with me. (Don’t ask.)

So if I had to guess, I’d say much closer to .5mm / than to 1mm. AND I’ve never replaced one either… on the six minis that I still currently have (600 miles away). Of course, I’d be more concerned about this IF I didn’t have all of the screws that actually hold the mobo in place.

*And ahh... I think Ninester replaced his back in 2019 with this:

https://www.amazon.com/gp/product/B00UYTTLI4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

See his post: https://macos9lives.com/smforum/index.php?topic=4937.msg35828#msg35828

[Wozniattack]

Sorry.

I’m 600 miles from my calipers @ present but I do just happen to have one of those pads stuck to the top of a bottle with me. (Don’t ask.)

So if I had to guess, I’d say much closer to .5mm / than to 1mm. AND I’ve never replaced one either… on the six minis that I still currently have (600 miles away). Of course, I’d be more concerned about this IF I didn’t have all of the screws that actually hold the mobo in place.

*And ahh... I think Ninester replaced his back in 2019 with this:

https://www.amazon.com/gp/product/B00UYTTLI4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

See his post: https://macos9lives.com/smforum/index.php?topic=4937.msg35828#msg35828

I truly appreciate it. It’s been so hard to fine information on it. The few places that sell the original Appel pads want over $50, not including shipping and customs to Ireland.

I’ll likely replace mine with the GELID extreme 0.5mm pad then, it’s good enough for overclocking VRMs and RAM on the RTX 4090, should do the mini well, and rather cheap here on Amazon.

One suggestion I got off ifixit was to stack business cards next to the pad to try and gauge the height, as you’re the first one to have one to hand!

[aBc]

THANK YOU for the mention of the GELID extreme 0.5mm pad as a possible replacement.

[Wozniattack]

THANK YOU for the mention of the GELID extreme 0.5mm pad as a possible replacement.

The Gelid Extreme pads are 80x40mm, and come in 0.5, 1, 1.5, 2, and 3mm sizes to just seem the best option. The reviews I saw of them dropped VRM, and memory hotstops by up to 20 degrees. Should be well worth it, and a single pad could be used on a few Minis then.

I’ll get the pads ordered end of the month and report back.

[n8blz]

Hi folks,

I recently repasted my mini following this, but wanted to ask about the thermal pad on the bottom chassis for the graphics chipset. Why does no one ever seem to replace it? Mine seems a little gunky looking from two decades, and the service manual states it needs to be replaced if the logic board was removed. Does anyone happen to know the thickness. Can’t find that anywhere even looking up the part number.

I’d like to give the mini even more life, and I use it to play some classic games also.

It looks about 0.5mm, but in the service manual the photo appears 1mm nearly.

I replace these every time, any thermal pad of the thickness already mentioned works. No reason not to since you’re in there, even if pads last a lot longer than paste.

[aBc]

Thanks n8blz. Now I suppose that I’ll need to replace such a pad in order to determine if there’s any temperature difference measured on the bottom? (Still, I place the minis up on little feet to improve air flow underneath, instead of allowing them to rest on their h-o-t rubber bottoms.) Anything to possibly increase their lifespan. (20 more years?)

[Wozniattack]

Hi folks,

I recently repasted my mini following this, but wanted to ask about the thermal pad on the bottom chassis for the graphics chipset. Why does no one ever seem to replace it? Mine seems a little gunky looking from two decades, and the service manual states it needs to be replaced if the logic board was removed. Does anyone happen to know the thickness. Can’t find that anywhere even looking up the part number.

I’d like to give the mini even more life, and I use it to play some classic games also.

It looks about 0.5mm, but in the service manual the photo appears 1mm nearly.

I replace these every time, any thermal pad of the thickness already mentioned works. No reason not to since you’re in there, even if pads last a lot longer than paste.

Truly appreciate it folks. I constantly see folks on YouTube ignore the pads, or say they can just be reused. But after 20 years is well past due.

Thank you especially for the measurements

[aBc]

Hey Ranier!

If possible and you haven’t already begun the process, would you be so kind as to measure and report the exhaust air temperature of you G4 Mac mini AFTER it has been running for 10 minutes and @ 15 minutes (from a cold boot)?

Also: which specific mini? 1.25, 1.33, 1.42 or 1.5 GHz?

AND concerning n8blz’s posts above… could / would you also record the temperature of the bottom rubber pad (closest to area where the GPU would be located underneath) while the mini is still fully assembled (again at the 10 & 15 minutes of runtime)? Even if you don’t opt to change the GPU’s thermal pad.

I’m always in the (what now seems like eternal) prep mode for even more temperature studies of these Mac minis. New pads, heatsink paste and even a copper heatsink replacement.

Thank you!

[Wozniattack]

Hey Ranier!

If possible and you haven’t already begun the process, would you be so kind as to measure and report the exhaust air temperature of you G4 Mac mini AFTER it has been running for 10 minutes and @ 15 minutes (from a cold boot)?

Also: which specific mini? 1.25, 1.33, 1.42 or 1.5 GHz?

AND concerning n8blz’s posts above… could / would you also record the temperature of the bottom rubber pad (closest to area where the GPU would be located underneath) while the mini is still fully assembled (again at the 10 & 15 minutes of runtime)? Even if you don’t opt to change the GPU’s thermal pad.

I’m always in the (what now seems like eternal) prep mode for even more temperature studies of these Mac minis. New pads, heatsink paste and even a copper heatsink replacement.

Thank you!

Once I order some stuff end of the month, I’ll also get a temp probe. At the moment I only have the cooking ones, and one for human temp.

It’s a good idea, and I’ll see what I can do. I’ll run some dungeon siege for about 15 mins and get temps, replace pad, and do the same.

[Wozniattack]

Just wanted to pop back. I replaced the old thermal pad today, and it was well grumpy from age. New 0.5mm pad working well. I ran Dungeon Siege for over 30 minutes before and after. Old hot spot was 41.2c. Then after replacing the pad is dissipating a little more heat after another over 30 minutes hot spot on base of chassis was 43.3c.

Pretty decent little increase, and some peace of mind. The photo is the old pad on top of the new one before I took its film off. Can see it was old one’s top was rather dry.

The new pad was 80x40mm, so just used a craft knife to cut it.

*The second image below (the .png file) added for those with smaller monitors. -aBc

[aBc]

Finally got back to this after Wozniattack’s post above concerning the old thermal pad replacement in the G4 Mini. And I finally got a dual probe temperature meter to use for the eventual copper vs. normal heatsink comparisons - so I used that here for my baseline temperature results from a 1.5 GHz Mini. AND since I do not have Dungeon Siege to run and monitor temps with, a comparison with W’atak’s temps is sadly not completely valid for comparison. However when (and if) I ever get around to changing out that thermal pad, the numbers noted below should / could be (with temps taken again after a thermal pad change).

It is interesting (to me anyway) that W’atak’s recorded temperatures of 41˚ & 43.3˚C [106.16˚ & 109.94˚F] are so close to the HIGH maximum exhaust air temps that I recorded back in 2023. http://macos9lives.com/smforum/index.php?topic=5955.msg52638#msg52638

“Initially, all tested Mac mini fan exhaust temps (mini case covers off) here reached 84˚ (maximum) soon after boot and remained there steady. With the exception of two Minis here that quickly went to just above 100˚F almost immediately. [There’s a BIG clue.] Renewed the CPU thermal paste and those temps then matched the 84˚. (And all with no White Case adapter covers in place ~ “naked”.)”

Now here today with a lower ambient room temperature AND the mini’s cover-in-place, the max exhaust temp was only 82˚F (after 30 minutes). So undoubtedly, ambient room temperatures have some bearing on all of this too. It’s still quite “Winter cool” here. When my previous exhaust temp tests were done, the room was 76˚F. (Nearly 10˚ hotter.) And really all under no load other than displaying the desktop on a monitor in millions of colors. Baseline testing.

Anyway, ATAB = Ambient Temperature @ Boot. And I used the T1 Sensor taped directly underneath the center of the thermal pad on the rubber bottom of the mini. The T2 sensor was placed inside the exhaust air vents on the back of the mini. Minutes noted are elapsed runtimes after a cold boot...