ReverendGadgetBoy

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hokay well i gots me a little story for that you should hear:

i was working on ventilation for my grapics card, and i came to the conclusion that i needed a pci slot fan that would work as an intake. now, it just so happens that i own a pci slot fan. however, when i got it out, i was dismayed to find that it could not be reversed, and would only work as an exhaust. that set me thinking, and i decided "since if you reverse the current through a motor it spins in reverse, why not try that with the fan?" i figured that there was no reason it shouldnt work, and the worst case scenario was that i blew my already useless pci slot fan.

ACT II
so i cut the two wires leading from the molex plug to the fan. i stripped a small amount from each one, and then wired the red wire to the black and the black wire to the red. so theoretically everything should work now. the motor would spin in reverse, and the fan would suck air in instead of blowing it out. so i plugged everything back in, and turned my system on.

ACT III
hmmm. nothing from the fan. it didnt spin in either direction, didnt give any indication of doing anything at all. i switched the wires back, and lo and behold, it worked again. so i tried one more time. FRAILURE!!! again nothing from the fan.

now for the bad part:
while the system was still on and the fan reversed, i accidentally touched the exposed parts of both wires. aka the red wire from the molex plug, the black wire from the molex plug, the red wire from the fan, and the black wire from the fan all made contact at the same time. this rather large spark flew from the two wires, and the computer immediately shut off. and would not turn back on again. i tried different things for several minutes, becoming increasingly panicky. i reset the power switch on the psu, and unplugged it for 5 minutes. when i turned it on again it worked.

now for the more bad part (act 5?)
when i first built this system, my corsair xms2 ram did not work at its rated speed and timings. naturally i OCed it back to its standard specs. when the computer booted up again though, it said that the overclock had failed. i did not understand this at first, because i could not think of any OC that i had performed, as the ram had worked fine before. but i was going through my bios when i noticed that the ram was un OCed. i naturally set it back to what it should be at. however when i saved my settings and exited, the computer did not reboot. when i did a hard shutdown and rebooted, it gave me the same message about the OC failing. i played around with the settings in bios, and through trial and error discovered that the setting that was causing the problem was when i changed the option that says "determine DRAM timings from SPD". changing the frequency to the rated DDR2-800 caused no problems. it wasnt changing the timings that was causing the problem either. it was just that one thing that said "determine DRAM timings from SPD". i could set the timings to anything if that was set to manual and it would fail. but if i set it to auto, the computer would boot. the timings are not causing the problem, just that setting.

ACT VI (damn is this long)
so basically, did i break my mobo, ram, or both. i have since flashed the bios, and it didnt help. i reset the cmos also. no help. id like to determine how much damage i did, whether it is fixable, and whether using this computer is likely to damage anything else (aka is my psu a time bomb)?

any help AT ALL on this problem would be appreciated. any similar experiences would be great to hear of.

Thank anyone who makes it this far for reading my gigantinormous post. PLEASE help me.
 

mad-dog

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Congratulations, you just trashed the voltage regulator and diode among other things on the motherboard since the fan was plugged into the motherboard when the wires crossed.....remedy: obtain new motherboard or send back to manufacturer for repairs
Oh, and one other thing, those particular fan motors aren't reversible..
 

derek2006

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The fan won't spin in reverse because there is a diode on the fan that only lets the electricity go one way, not in reverse because it may ruin the brushes in the motor.

I can't find where he said he put the fan into the motherboard my understanding is that he plugged it into a molex connector. Also I have done that many times on my computers where 2 wires touch and the computer shuts down and the overclocks go back to stock. Usually I just unplug the computer for 30 seconds and it fixes the problem. I just have to put all the overclocks, settings, date and time back. I have never had a problem with putting all the overclocks back though.

Are you sure u put the settings back the way they were before. Maybe the ram needs more voltage? When the motherboard detects the SPD for the ram settings it probably sais something like 5-5-5-15 800mhz at 2.1v. And when you try to put them at 4-4-4-12 or whatever by selecting manual maybe your forgetting to put the voltage back up where your motherboard maybe automatically puts 1.8v to the ram when it needs 2.1v or so.
 

locky28

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Haha thats spectacular this must be posted in the 'Worst PC Screw Ups' thread.

As for you query, if i had to make a guess I'd say that it's just your PSU that's had a visit from doctor death, seeing as the Fan card connected to a molex rather than mobo pins I don't think any other components would've been affected.

Of course I'm assuming that, as you mentioned, you have one of the slot filling cards that DO NOT need to plug into the PCI slot on the mobo but just sit over the slot.
 

derek2006

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Of course I'm assuming that, as you mentioned, you have one of the slot filling cards that DO NOT need to plug into the PCI slot on the mobo but just sit over the slot.
If he had it plugged into the PCI slot then yes that would be bad but if it went into the PCI slot I don't know how he would of changed the wires around.
 

mad-dog

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Good point, i was assuming he had plugged the fan into 1 of the fan channels on the mobo using a molex/modular adapter cable
 

ReverendGadgetBoy

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well i didnt plug the fan into the mobo in any way, it was just into the psu. i like what i hear about derek2006 having this happen before. its strange though because i did not have to reset the time, just my bios settings. as in not the time setting. i always set the RAM voltage to auto, which is what i did the first time i OCed it. i also tried setting different voltages (1.8, 1.95, 2.1) and it made no difference. its just that one setting called (determine DRAM timings from SPD). Even if i turn that to manual but leave the settings on what their default is, it wont boot. i havent tried UNDERCLOCKING the timings, but my guess is even that will make it not boot because it would involve changing that one setting. ill give that a spin.

ps thanks for the help about the fan. does anyone know of a high quality slot fan that can work as an intake too? or any OTHER mods i can do to this one to reverse it? i dont mind breaking it by mistake.

and i like that idea of me being in the worst pc screwups of all time. more fame for teh GadgetBoy!!!!!!!!!!!!!!!!!!! j/k.
ps. thats not really worst screwup material is it? everything still runs, admittedly not as fast.
 

derek2006

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Ill do some research to find a way to wire the fans circuit to maybe skip the diode so the fan will work in reverse. I forgot that most computer fans don't use brushes like regular motors. but they have 3 stationary electromagnetic things. And then the fan with a circular magnet inside it so it might work. My uncle gave me his dead powersupply today that has 2 fans i will experiment with them to see if i can get it to work
 

derek2006

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There is a easier way and a funner harder probably impossible way:
Easy way mount the fan outside the case and have it blow in.

Harder way (chances are you may break it):

Ran into some problems when trying to do this. (Couldn't find my soldering tip). But I can give you an untested way that might work.
Parts need:
Solderer(with tip)
Solder
Opposite transistors

1.Ok first you need to open up the pci fan and pop off the fan from the base. Do this carefully so you don't break the plastic. Underneath the fan is something that might look like this and a circuit board underneath it. I couldn't pry the circuit board up but give it a try. And then Glue it back down when done.

L_electric_motor_cutaway.gif


Also their should be parts a diode:
diodes.JPG


Transistors:
2sc1815e.gif


And some resistors:
resistor.gif

Don't mess with the resistors or you could fry the transistors they can have current go both ways so they don't need to be put on reversed.

2. To by-pass the diode you could solder a wire from one side to the other or unsolder it and put it on backwards.

3. You can put it back together and see if it then spins the opposite way. But chances are it wont because the transistors. Their are 2 types of transistors PNP and NPN (for stuff like this anyway). PNP needs a positive charge and NPN needs a negative charge. To tell which one you have have the flat face of the transistor face at you. On the top of the transistor there should be a little notch or dot. If the dot is on the left of the transistor it is PNP if it's on the right of the transistor it is a NPN. You need to get the opposite transistor for this to work. Mine were PNP transistors so I need a NPN for it. There should also be a model number on the transistor like 2n3904 or C3202. Get the opposite sex transistor with the closest model number (worked for me so far) if you can but usually any opposite transistor will work. Get it at a store like http://www.futurlec.com/index.shtml. They haven't let me down yet my only complaint is like 1 week shipping.

Remember this works in theory but u said it doesn't matter if you break it so...
 

threep

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Most computer fans will only spin in one direction. The fins are curved to provide maximum thrust in that direction. Reversing the spin direction would seriously reduce the flow rate. Some small fans (like those used in laptops and on video cards and chipsets) will be permanently damaged by reversing the leads.

I don't know what the fan looks like on the device you have, but is it not possible to simply physically take the fan assembly off the unit and flip it around, so that the fan still spins the same direction, but now the flow is going into the computer instead of out of?

Remember, optimum airflow designs within most computer cases have cool air entering in thru the front of the case, flowing across the memory, cpu, video, etc. and exiting out the back. Changing the air flow dynamics will certainly affect the cooling capabilities of your computer.

8)
 

locky28

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Wow, good work Derek that was clear and informative.

So your saying it's possible to just bypass the risistor? I've never understood ectronics much so could you tell me, a risistor just restricts the flow of electricity to one direction correct? Thats what i gathered from your post anyway.
 

derek2006

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I agree that you wouldn't get as much air flow with it spinning in the opposite direction. Maybe just mounting it outside would be better? Or somehow design a duct that sucks air from outside and right into the GPU fan.

Also I forgot to mention that you should try running memtest or something on that ram. Maybe something did happen to it. If you can RMA it.
 

derek2006

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Yes resistors just restrict the flow, like say you have 12v of electricity and a component only needs 5v a resistor would only allow that 5v to pass through. If you by pass a resistor though and the delicate component gets that 12v it will release the blue smoke and be no more. A diode is what restricts the flow in one direction. So it can't operate backwards or cause damage. But I never had a transistor of mine fry because the voltage flow was backwards so I would just by pass it.
 

derek2006

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I can't think of a way to reverse it. Unless you remove every blade and some how reglue it in the opposite direction. But i doubt the glue would be strong enough to hold up especially at high speeds.
 

ReverendGadgetBoy

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well the fan cannot be flipped over. it has a solid piece on the other side, meaning that no air would be able to get in. i like the harder of the two mods that were suggested. i dont really wanna put the fan outside, because its really large, so ill try to modify it. are there no fans commercially avaialable that work as intakes? i need one that intakes from a pci slot, and directs the air upward. that would be the most helpful.
 

locky28

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Maybe see if you can get your hands on one of the Graphics cooling parts from an Antec P180, the original version of that case had a plastic part with a fan that was vertical to the case and blew outside air onto the GFX cards, a lot of people took these off because they were inefficient and a pain in the A$$.
 

derek2006

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I found my solder tip. It didn't work for me. I fried my last transistors (2 of them so not a big deal) I had laying around. I fried the original transistors on the fan by having the soldier on to long. I just couldn't get the solder to stick. Since it was broken already I went looking for another way that I should of done earlier. I took off the circuit board from the back of the fan. And the little printed wires (don't know what there called) that went to the fan there. I should of just scratched them off so they don't make contact anymore and then solder my own but in reverse. That way I wouldn't of had to mess with any of the components and they would operate normally but the fan would still run backwards. I don't have any more fans though to test this on. So if you try any of these ideas I hope you have really good luck.