Mystery 2 Pin "J2" connector on Cube?

Goftrey

macrumors 68000
Original poster
May 20, 2011
1,844
70
Wales, UK
I've been meaning to ask this for a while, and I can't seem to find any information on this weird little connector other than the fact it outputs 5v (variable). Everyone I've come across doesn't seem to know what it was designed to do.



Does anyone know what it's there for? Does it have any use?
 

bunnspecial

macrumors 604
May 3, 2014
6,722
3,275
Kentucky
I plugged a fan into it on one of mine :)

The case door fan from an MDD fits perfectly in the space between the graphics card and the logic board, and the plug fits that connector.

I don't know if a fan in that particular location with that arrangement actually accomplishes anything, but I had the fan and it fit and runs.
 

Goftrey

macrumors 68000
Original poster
May 20, 2011
1,844
70
Wales, UK
I plugged a fan into it on one of mine :)

The case door fan from an MDD fits perfectly in the space between the graphics card and the logic board, and the plug fits that connector.

I don't know if a fan in that particular location with that arrangement actually accomplishes anything, but I had the fan and it fit and runs.
Does that fan run off 5V in the MDD then?

If it works then I may as well follow suit and rip one out of one of my MDD's. This 6200 sure does get toasty.
 

MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
Does that fan run off 5V in the MDD then?

If it works then I may as well follow suit and rip one out of one of my MDD's. This 6200 sure does get toasty.
you can use ANY computer fan with that connection. I added fans to my MDD and pluged a regular 3 pin PC fan into that plug and it works just fine. You can use one from a MDD u could use a PC fan that has a 4 pin molex connector and just plut it in between the HDD and power supply (if it would work, I don't have a Cube so i cannot speak for its space confinements). You can even use the 2 pin leads off an old PC Switch or LED that plugs into that spot perfectly too (the modified OEM MDD fans in mine use old LED leads).
 

jbarley

macrumors 68040
Jul 1, 2006
3,773
1,616
Vancouver Island
you can use ANY computer fan with that connection. I added fans to my MDD and pluged a regular 3 pin PC fan into that plug and it works just fine. You can use one from a MDD u could use a PC fan that has a 4 pin molex connector and just plut it in between the HDD and power supply (if it would work, I don't have a Cube so i cannot speak for its space confinements). You can even use the 2 pin leads off an old PC Switch or LED that plugs into that spot perfectly too (the modified OEM MDD fans in mine use old LED leads).
How did you manage to plug your fan into that plug which in the picture is on a G4 Cube, if as you say you do not have a Cube?
 

Goftrey

macrumors 68000
Original poster
May 20, 2011
1,844
70
Wales, UK
Juts for future reference;

I just plugged a 3 pin 12v Bitfenix Spectre fan in to the connector to see what would happen, and as expected, it didn't spin up.

However the 2 pin MDD case fan I have did spin.

I'm presuming the case fan in the MDD also runs off 5v, and that's why they're compatible with each other.

Most 12v fans won't run on 5v, hence why the Bitfenix didn't spin.
 

MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
How did you manage to plug your fan into that plug which in the picture is on a G4 Cube, if as you say you do not have a Cube?
The MDD has those same connectors for fans. The MDD has four. 1 for the main fan one for the side fan one near the heatsink (all are around 4.7 Volts) and then the one by the AirPort or AirPort Extreme slot is a constant 12V.

----------

Juts for future reference;

I just plugged a 3 pin 12v Bitfenix Spectre fan in to the connector to see what would happen, and as expected, it didn't spin up.

However the 2 pin MDD case fan I have did spin.

I'm presuming the case fan in the MDD also runs off 5v, and that's why they're compatible with each other.

Most 12v fans won't run on 5v, hence why the Bitfenix didn't spin.
That is not the case. You plugged it in wrong. That fan connector needs to be hook with the red pin to the right hence when you use a PC Fan the "tabs" on the plug need to face down opposite of the tab on that plug. I broke off all my tabs by accident in the MDD and it works fine the RPM Sensor wire hangs to the right of the connector (facing the connector). All 12V computer fans will run from between 3 and 12V. However not many computer fans have good airflow at anything below 7V.
 

Goftrey

macrumors 68000
Original poster
May 20, 2011
1,844
70
Wales, UK
That is not the case. You plugged it in wrong. That fan connector needs to be hook with the red pin to the right hence when you use a PC Fan the "tabs" on the plug need to face down opposite of the tab on that plug. I broke off all my tabs by accident in the MDD and it works fine the RPM Sensor wire hangs to the right of the connector (facing the connector). All 12V computer fans will run from between 3 and 12V. However not many computer fans have good airflow at anything below 7V.
I can assure you I didn't plug it in wrong. And it's a fact that not all 12v fans run on 5v. Depending on the fan's motor, some spin without an issue (at a lower rpm), some try to spin and fail, and some simply don't spin at all.
 

MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
I can assure you I didn't plug it in wrong. And it's a fact that not all 12v fans run on 5v. Depending on the fan's motor, some spin without an issue (at a lower rpm), some try to spin and fail, and some simply don't spin at all.
If its a low CFM usually those wont spin at 5V because even at 12V they produce next to nothing in airflow. I have yet to ever find a 5V computer fan

CORRECTION: I have yet to find a 5V computer fan larger than 50mm
 
Last edited:

bunnspecial

macrumors 604
May 3, 2014
6,722
3,275
Kentucky
FWIW, I think that the fan in my Cube at least accomplishes something.

I have two Cubes, and I've upgraded both with GEForce 2MX cards, although the desktop version in both cases and not the Cube specific version. As most Cube tinkerers probably know, the faceplates on these cards are interchangeable with the stock Rage 128, although the desktop version of the card has a comparatively small heatsink compared to the Cube version. The desktop cards have a reputation for running very hot in the Cube. I found this out the hard way, as I made the mistake of disassembling one of mine immediately after powering it off once, and the heatsink was hot enough to raise a blister on my finger.

In any case, as I mentioned, on one of my Cubes I have an MDD case door fan connected to J2 and dangling in the space between the logic board and the back of the video card. This really isn't where the airflow should be to cool the video card, but I figured it wouldn't hurt anything.

After using the one with this extra fan for a little while last night(both my Cubes have base fans tapped into the molex connector on the optical drive), I found the video card at least a little bit cooler than on the one without the fan. It's not much of a difference, but at least I feel like this fan is accomplishing something.