Author Topic: Guide to replacing the noisy fans in your G4  (Read 5156 times)

Offline Syntho

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Guide to replacing the noisy fans in your G4
« on: February 17, 2014, 03:57:05 PM »
The G4 MDD is nicknamed the windtunnel because it's loud. Let's take care of that.

Visit here for pictures, instructions and the official Apple document which will help you remove the internal hardware of your G4 to gain access to the fans.

http://www.xlr8yourmac.com/systems/g4_mirrored_drive_doors/noise_reduction/g4_ddr_noise_reduction.html

http://www.info.apple.com/usen/cip/pdf/g4mirror/fan_power_supply.pdf


There's a total of 3 fans that need to be replaced. One is the large case fan, and the other two are fans are in the power supply.
The easiest fan to replace is the case fan. We'll be replacing it with one called the SilenX 120x120x38mm - 18dBA - 90CFM iXtrema Pro Fan (IXP-76-18).



It's available on Ebay. All you have to do is follow the guide from Apple above, unplug some cables, remove the front CDROM bay and switch the old one out with the new one.





The old fan comes with a 2-prong connector. The Silenx comes with a 3-prong connector. I thought that by plugging in just two prongs from the Silenx fan into the fan power plug that it would work, but it didn't for me no matter which two were plugged in.

Thankfully the Silenx also comes with a molex adapter. I plugged the Silenx into the adapter, then the adapter into the back of one of the loose molex connectors laying underneath the CDROM bay in the front



When installing the Silenx, you'll notice that it's not quite as thick as the original.

It may jiggle a little, but a little jiggle is no big deal. I got it as solid as I needed it to be but just to be sure, use some kind of tape and get it sat in there as firmly as you'd like.





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The power supply fans are another story. By following the Apple guide above, you can get to the point where the power supply is out of the computer totally. I didn't quite go that far and just left the bundle of cables still-routed inside the G4.



As you can see there's enough slack to get the power supply as exposed as you need it to be to start replacing the fans. I replaced the originals with some Everflow F126025DH fans.



Unfortunately these fans are hard to come by on their own, so I bought one Thermaltake volcano 5 heatsink+fan combo and one Thermaltake Volcano 6 Cu heatsink+fan combo.



Both of these have the Everflow F126025DH fans and all you need to do is unscrew them from their heatsinks.

Note 1: do NOT buy the Thermaltake Volcano 6 Cu+. The Cu+ has a different fan than the regular Cu. We want either a Volcano 5 or a Volcano 6 Cu

Note 2: Make sure you have a skinny screwdriver to fit into the top holes so you can reach the screws below.

When you have your fans ready and the power supply ready to be opened, there will be 2 screws on the side and 3 screws on top of the power supply to take out.
There will also be 4 screws holding the fans in place.

Take everything out. After they're out you can lift up on the side of the power supply and the side metal casing will come up a bit, exposing the internal area of the power supply.



You don't have to take it off completely since it'll lift up enough so that you can slide the two fans out.

When the two fans are out you'll notice that the metal casing that flips up a bit will reveal the area that the two fans are connected to.

Remove the connectors from the power supply's board. You'll notice that there's a little white, plastic cable tie holding the fans' cables together. Leave it in place. Take an X-acto knife and snip the two fans' red and black wires, but make sure to snip it more toward the fans, NOT near the connectors.

We're trying to salvage the connectors with some slack left over since we need the slack for later. After you've snipped them, pull the connectors out with the rest of the slack coming from inside the cable tie.



Once again we're going to notice that the original power supply fans are two-prong and that the Everflow fans are three-prong. Instead of taking out the wires and changing the connectors, what I did was also snip the wires on the new Everflow fans in the middle, leaving a bit of slack on those too.

At this point you're left with red, black, and yellow wires without connectors on the Everflows, and a red and black wire for the old connectors.

Completely cut off the yellow wires on the Everflows - we don't need them.

Now take your X-acto knife and strip the ends of all the wires, exposing the inner conductors.



All you have to do now is twist the red and black wires from the Everflows to the connectors of the old fans, then seal each one up securely with electrical tape.



Then just follow this guide in reverse order, reinstall the new fans, put the power supply back in, and give it a test run. Check to see if all of the fans are spinning.


Your G4 is now much more silent.


Any questions just ask  -afro-
« Last Edit: February 19, 2014, 09:42:44 AM by Syntho »

Offline Syntho

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Re: Guide to replacing the noisy fans in your G4
« Reply #1 on: February 17, 2014, 04:08:45 PM »
I'm going to have some detailed pictures for my guide posted by tomorrow. Will be back in the studio tomorrow to take them so I can show you  -afro-

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #2 on: February 17, 2014, 07:20:48 PM »
Thanks Syntho...

Some other info I posted previously...

If your unit is very loud, you can check the internal fan (large one under Optical cage) and see if it is a Papst fan ("Multifan 4212H", 12 V, 5.3 W)... if so the Apple noise modification was applied before yours shipped. The Mod by apple was free at the time (under warranty in late 2003 & 2004) and it involved a different power supply (360W instead of 400W) and the Papst fan I mentioned.  There are also mods you can do yourself to quiet it down a bit.... If it does not bother you, then leave it stock... it looks so pretty new

For more info. on Mod and quieting an MDD, one resource is below:

http://www.splefty.com/G4mod/

Offline Syntho

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Re: Guide to replacing the noisy fans in your G4
« Reply #3 on: February 19, 2014, 09:43:50 AM »
Ok the pics are up. I took a few from elsewhere but added in some of my own  -afro-
« Last Edit: February 19, 2014, 09:50:23 AM by Syntho »


Offline robegian

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Re: Guide to replacing the noisy fans in your G4
« Reply #5 on: May 01, 2014, 06:52:38 AM »
Hi, I did something similar too. I wrote a report here:
https://68kmla.org/forums/index.php?/topic/22414-power-mac-g4-mdd-successfully-silenced/

By the way, I didnt' cut the two PSU's fans power wires — rather, I cut away the third wire and I replaced the connector of the two power wires.

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #6 on: May 31, 2014, 09:19:16 PM »
here i am having to do this operation AGAIN.. my 2nd time now LOL
 :'(

for my new single 2003 1.25ghz... *sigh*
deep breath

step1) remove the vertical hard drive caddy under the power supply, apply force+ press firmly on the screw with screwdriver to avoid stripping the screw, hit the plastic latch on the left side of the caddy to allow it to slip up and then be pulled out from its placement remove the hard drive connections and remove the caddy + Set it aside

step2)
slide teh back plate off the back of the cdrom (if its there still) to allow for disconnection of cd/dvd drive connections for data/power, then remove 2 screws attaching the dvd drive cage + set them aside, pull the drive cage towards the rear of the unit and it will disengage for removal and set the dvd cage aside

step3) using allen key hex tool remove 3 screws holding power supply in place.. free the power supply and then use X philips headscrew driver to open the remaining screws on all sides of the psu to gain access inside the psu by removing the side panel of it


« Last Edit: May 31, 2014, 09:53:33 PM by chrisNova777 »

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #7 on: May 31, 2014, 09:55:58 PM »
here i am having to do this operation AGAIN.. my 2nd time now LOL
 :'(

for my new single 2003 1.25ghz... *sigh*
deep breath

step1) remove the vertical hard drive caddy under the power supply, apply force+ press firmly on the screw with screwdriver to avoid stripping the screw, hit the plastic latch on the left side of the caddy to allow it to slip up and then be pulled out from its placement remove the hard drive connections and remove the caddy + Set it aside

step2)
slide teh back plate off the back of the cdrom (if its there still) to allow for disconnection of cd/dvd drive connections for data/power, then remove 2 screws attaching the dvd drive cage + set them aside, pull the drive cage towards the rear of the unit and it will disengage for removal and set the dvd cage aside

step3) using allen key hex tool remove 3 screws holding power supply in place.. free the power supply and then use X philips headscrew driver to open the remaining screws on all sides of the psu to gain access inside the psu by removing the side panel of it

omg i think the fans i got are just as loud as the originals.. :(
ok my mistake i mistook the original for the new one lol they are both black
MAN THESE FANS ARE LOUD
and they sure do push alot of air..
thing is i never had a problem with it overheating..
i dont understand why they were so worried about it ..
i guess maybe its a big problem if u live in a hotter area like down in cali or something

« Last Edit: May 31, 2014, 10:17:45 PM by chrisNova777 »

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #8 on: May 31, 2014, 10:48:08 PM »
having just done this for the 2nd time i can say u can easily just forgo replacing the larger mid placed fan
its not really the culprit at all. 90% of the annoying noise comes from these small 2 fans inside the PSU.

Offline rvense

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Re: Guide to replacing the noisy fans in your G4
« Reply #9 on: October 21, 2016, 02:50:03 PM »
Would replacing the CPU entirely be feasible? It's an odd shape as far as I can tell from the pictures.

There's an MDD near I'm thinking about picking up...

Offline InspectorG

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Re: Guide to replacing the noisy fans in your G4
« Reply #10 on: March 07, 2017, 04:16:17 PM »
Sorry for the thread necromancy, but does anyone know if the factory 120mm fan runs at a constant RPM or if it adjusts to processor temperature/system load?

Offline GaryN

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Re: Guide to replacing the noisy fans in your G4
« Reply #11 on: March 08, 2017, 12:02:59 AM »
In OSX, it's fed variable voltage controlled by a temp diode near the CPU's.
In OS9, not so much. The OS doesn't know about the temp sensor. There was a firmware update that attempted to reduce the noise somewhat by slowly cycling the fan speed… some would say it's actually more annoying…

There are a zillion threads all over the net about how to replace the fans in the MDD - especially the two in the PSU where most of the noise actually comes from. Only one that I've seen accurately measures the difference in average or peak temps in the PSU afterward. They're mostly too busy patting themselves on the back for quieting the damn thing down.

I'll say this once: I've been using an MDD for years and years, having come to it directly from a G3 desktop. I know a few things about MDD's.
The PSU runs anywhere from fairly cool to blazing hot depending on load.
One proc, 1 or 2 HDD's, 1 PCI card, mild word processing and the thing will be happy forever.
Two procs, 4 HDD's 3 or 4 PCI cards and a couple of Cinema Displays juggling 40 audio tracks… you have changed out those fans at your peril.

The PSU will - not might - will… die and probably die sooner than later.

It will run hot and give absolutely NO indication of imminent death until one day when it just goes poof… probably just before an important session. I know this because it's happened to me 3 times. So, here's the bottom line:

* You can change fans, locate the computer as far away from your primary area as practicable, build a "quiet box" (that's what I ultimately did), buy a couple of small temp sensors with their own readouts and keep an eye on them, be aware of how hard you're pushing the unit or some / all of the above. Still, my best advice is:

* If you're going to need reliability and quiet, buy two MDD's and put the PSU from the second one on the shelf…there will come a day when it saves your ass.

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #12 on: March 08, 2017, 08:11:26 AM »
There are a zillion threads all over the net about how to replace the fans in the MDD - especially the two in the PSU where most of the noise actually comes from. Only one that I've seen accurately measures the difference in average or peak temps in the PSU afterward. They're mostly too busy patting themselves on the back for quieting the damn thing down.

...you have changed out those fans at your peril.

The PSU will - not might - will… die and probably die sooner than later.


Garry, as usual, you are spot on :)

As we have mentioned previously here, It's all about CFM... it you are not moving enough air... the Power supply will cook. IMO, Any MDD stock PS Fans moving less than 25CFM will eventually cook themselves.

There is a delicate balance of "quieter" and proper air flow... and there are many great alternatives that have been discussed in other posts.  Unfortunately, very "silent" fans may result in a "silent" MDD that does NOT power on.

Offline mrhappy

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Re: Guide to replacing the noisy fans in your G4
« Reply #13 on: March 08, 2017, 08:29:43 AM »
I bought replacement fans for mine but never installed them... Having too many other loud fans, I just bought a 12" long masonry bit to drill through an adjoining wall for a 'machine room'... my project for this week! ;D ;D