Stupid fan wiring...

mike31154 · #1 06-14-2015, 05:39 PM

Photo would certainly help sort things out. What colours are the 3 wires on the fan? There is a standard colour coding for DC circuits, but you never know these days. It's 12VDC so to run the fan you really only need 2 wires, + & -. The 3rd wire is, as already mentioned, either speed control (requiring additional external circuitry) or for the LEDs.

If you have a 9 volt battery kicking around, it should be easy to find out which are your +- leads. You'll need to cut off the molex connector & strip the wires, or remove the pins. With a jewellers screwdriver, you can generally push the pin out of a molex connector. They have a metal tab that locks the pin in place. Touch the wires to the 9V battery terminals & see in which configuration the fan spins up. Might even light up the LED lights. The fan should run with 9 volts, or at least try to once you get the polarity right. It may even run in either direction if it's reversible. To replace the molex & have a simple interface rather than soldering etc, an adapter as shown in the link below will come in handy in the future. Allows you to adapt your fan wiring to most any wall wart with the standard DC pin connector. Your local electronic supplier may have some of these in stock.

http://www.ebay.ca/itm/DC12V-Power-P...item259ceb4652

I have a bunch of them to adapt my DIY LED strips.

With respect to the LEDs being waterproof, I doubt your fan itself is waterproof either, being designed for a computer (dry environment). The solder connections will all be relatively exposed unless the fan is rated as being water proof or water resistant. Best to keep it all away from a humid environment. Not a big deal with regard to personal safety with 12VDC, but over the long term, exposed to moisture or excess humidity, the various solder connections will corrode. Having said that, I've used standard 12 volt fans in DIY lights over my tank for years without issue.

Myka · #2 06-14-2015, 08:33 PM

Thanks for the help Mike, I'll test with a 9V battery. Good idea! At least then I should be able to figure out if the LEDs are on the third wire or not. The wires don't have color coding - they are wrapped in clear wire coating and I can see the bare wires through the clear coating. The fan is not rated for moist environments, and I don't expect it to last forever, but for $7 I can replace it once a year if I need to.

It's going in the back wall of my stand to help move moisture out of the stand.

babnika · #3 06-14-2015, 08:39 PM

I am currently running 5 120 mm fans off one of these power supplies.these were purposefully built with the molex connector already built on. your fan should have come with an adapter they also carry them there plug & play

Myka · #4 06-14-2015, 08:44 PM

Quote:

Originally Posted by babnika

I am currently running 5 120 mm fans off one of these power supplies.these were purposefully built with the molex connector already built on. your fan should have come with an adapter they also carry them there plug & play

It might not work because only 2 of the 3 wires go into the Molex. If I use the Molex, the third wire is still to be accounted for. If the third wire is indeed for speed control, and not the LEDs, then I'm golden. I'm going to do the test Mike mentioned with the 9V battery, then take a trip to my electronic shop and see what I can fabricate.

WarDog · #5 06-14-2015, 09:07 PM

Mindy, don't worry about the number of wires. The third wire is nothing to be concerned about. One is + and one is -. It really is plug and play with the power supplies that are linked at the beginning of the thread. Just need to use the supplied 3 to 4 pin molex (supplied with fan) and plug into power supply. I went through all this when I installed mine. Only problem I had was I needed to switch one of the pins on the molex to line up with the molex on the power supply. Its really easy peasy!

WarDog · #6 06-14-2015, 09:18 PM

Here are the only two pics I have of the install. You will be surprised how hard it is to find the power supply at any local electronics store. The Source store is a joke now-a-days, much better when it use to be Radio Shack, for electronics anyways. Lots of power supplies on Ebay, but who wants to wait that long? I ended up getting the power supply from my local NCIX, and just added the extra unused hardware to my computer junk box.

newsaltfan · #7 06-15-2015, 01:47 PM

Mindy, take a trip to B&E electronics. Those guys will help you out. well I'm guessing they will, the guys that were in the Regina store helped me on several occasions.

mike31154 · #8 06-15-2015, 02:12 PM

Quote:

Originally Posted by newsaltfan

Mindy, take a trip to B&E electronics. Those guys will help you out. well I'm guessing they will, the guys that were in the Regina store helped me on several occasions.

^ This! Looks like these folks will have pretty well anything you need. No need to wait for shipping with online shopping for these kind of parts since you have a bona fide electronics supplier in Saskatoon. I see they have an online presence as well & stock molex connectors. Molex parts will only cost a few bucks, then all you need is any small 12 volt power supply. They should even have the special tool to remove & insert Molex pins. Either cut the connector off, replace with molex or get an adapter like I linked to & cut the molex off your fan. I've recycled a few small power supplies from obsolete equipment that are 12 volt. I'd be surprised if most of us don't have one or two cluttering up a junk drawer. Just need to make sure of the +- wire polarity when you hook it up.

http://www.be-electronics.com/Search...p?Search=molex

Humidity shouldn't be too much of an issue in your stand & yeah, for $7 not a big deal if the fan bites it after a year or even months. The B&E guys can probably recommend some better moisture resistant connectors for you. Next thing you know, you'll be fabricating bigger & better electronic thingys.

https://youtu.be/L8Mfvv1PqpY