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View Full Version : Unplugging fan in G5.. will it cause the others to go bezerk?




JoeG4
Nov 1, 2011, 04:26 AM
I admit I'm posting this because I'm too lazy to experiment, figured it was worth a try! I'll pop in with my results later in the week if I remember.

My G5's backside fan (that little blower by the hard drive bay) wasn't working that well, and was allowing the memory controller to get too hot so I yanked the fan out and stuck a regular 80mm in its place. This has been working great, but out of concern I left the old fan hanging around next to the video card.

Does anyone know if running a G5 without a particular fan plugged in will cause the thermal panic mode? If so I'll just.. find another idea I guess, but I'd love to just get rid of it since the fan is clearly triggered by SATA activity and has a stupid noisy motor.



reddrag0n
Nov 1, 2011, 02:37 PM
No, the rest of the G5 fans don't go bezerk. I took out the hard drive fan and have a regular 80mm fan running off of a 3 to 4 pin molex cable and it runs just peachy without the thermal fan plugged in. I took mine out because it whined and that was the second G5 fan that was in there. I plan on taking all my fans and replacing them with faster and more silent fans. With my machine as it sits, each time i load a program, the fans ramp up to 747 sounding, then back to normal. To me this is very annoying.

JoeG4
Nov 1, 2011, 06:08 PM
This is good news then :) Thanks

vohdoun
Nov 4, 2011, 11:50 AM
No, the rest of the G5 fans don't go bezerk. I took out the hard drive fan and have a regular 80mm fan running off of a 3 to 4 pin molex cable and it runs just peachy without the thermal fan plugged in. I took mine out because it whined and that was the second G5 fan that was in there. I plan on taking all my fans and replacing them with faster and more silent fans.

How will that work? the front has a weird 8 pin connector for the main two for the radiator... any fan recommendations?

With my machine as it sits, each time i load a program, the fans ramp up to 747 sounding, then back to normal. To me this is very annoying.

Yes, it can be annoying. Though I get it a lot more when the room door is shut in the late evening.

JoeG4
Nov 5, 2011, 05:47 AM
Yea I pulled that fan out, nice to finally have it out ^^ No problems. Thanks! It's funny but the backside fan still registers at 51rpm even though it's unplugged. XD

vohdoun
Nov 5, 2011, 08:24 PM
Replaced it with a 140mm?

JoeG4
Nov 5, 2011, 09:10 PM
Haha there's an idea :D Nah, you can only fit 80mm fans in the top bay (but they do fit! BARELY, but they do fit!).

reddrag0n
Nov 6, 2011, 01:59 AM
vohdoun: I just used a normal 3 to 4 pin wire adapter for my single 80mm.

JoeG4: What can i do with the blower fan that sucks air from the backside of the logicboard? Is there any alternatives?

As for the rest of the fans, i was thinking of these fans to replace the 80mm ones. (http://www.silenx.com/quiet.fans.asp?sku=efx-08-15)
And these ones to replace the 92 mm fans. (http://www.silenx.com/quiet.fans.asp?sku=efx-09-15)

And above the CD rom, i was going to power all the fans from one of these. (http://ncix.com/products/?sku=30587&vpn=BP-XSP1M-BL&manufacture=Bitspower) It has the capability to run multiple fans at 12V so i woun't have to worry about ramp up noise from the G5. As for thermal readings, all my G5 reads is the temps of parts, not the rpm's for some odd reason.

JoeG4
Nov 6, 2011, 06:00 AM
lol, as I said twice now I have a regular 80mm antec in place of that little blower fan. Apparently in the last gen G5s, that fan is attached to the drive bay fan and that slides right out. On ours? Not so much, you have to disassemble almost the entire case to get that carrier out.

OTOH, it's held to the carrier with rubber standoffs, so if you pull really hard you'll be able to yank the fan off them. There's only 2 (top left - that is.. towards front of the case, and bottom right!) standoffs. So long as you've unplugged the fan, you probably won't damage anything (except maybe your hands if you manage to scratch against something when it suddenly gives way XD)

Behind that fan is a ~60mm hole attached to a thin duct which is pretty much the only place air comes up from behind the logic board. If you set an 80mm fan next to it, it'll do just fine... probably much better if you make up some kinda duct so that the fan is 'sealed' against the hole! Not sure...

My G5's memory controller runs stupid hot.. right now in a 75f degree room it's at ~60c with light CPU usage. Heavy usage will push that sucker closer to 70c. With the OEM fan it was going to 80!

vohdoun
Nov 6, 2011, 09:25 PM
Haha there's an idea :D Nah, you can only fit 80mm fans in the top bay (but they do fit! BARELY, but they do fit!).

I was thinking of getting a 140mm. Bigger, slower, quieter, more air to push.

vohdoun: I just used a normal 3 to 4 pin wire adapter for my single 80mm.


I have plenty of those. Though are the front 2 fans for the radiator 92mm? I have some good breezy quiet LED 80mm fans to use.

I wish I done this years ago but with all the sensors etc I thought it would have messed up the calibration and lots of weird peculiarities would have happened.

Scary what the Delta fans use for their power draw at max speed. The last I looked 60amp?

reddrag0n
Nov 7, 2011, 04:50 PM
Yep, the fans in the G5 (9 fan version) go like this.

behind CD rom, 1- 80 mm and 1 side mounted blower

In front of PCI and AGP cards, 1- 80mm

CPU bay area, 2- 92mm front intake fans, 2- 92mm exhaust fans

PSU, 2- 60mm intake fans

reddrag0n
Dec 19, 2011, 08:00 PM
Just an update, yesterday i pulled out the front two 92mm deltas and rewired two regular 92mm's with the original connection plug and so far it doesn't cause the machine to go bezerk. I plan on rewiring all the major fans and see if that causes my G5 to be quiet and not sound like a 747 under load. When it's idle, the mac sounds fine. It's just when i am doing anything that the fans run like hell. Even playing with the dock makes it ramp up. So hopefully the new fans i get will eliminate that noise problem altogether.