i know a lot of you are still cutting the + wire on the fans and just wiring it to a 12v spot on the board, altho this dose work there is an easier way that doesn't require modifying the fans.

for a lesser fan speed cut the ground of both fans and run both ground wires to a power source (after doing the 12v fan mod).
for 7v ground to this point: Xenon, Zephyr/Falcon/Opus/Jasper
for 9v ground to this point: Xenon, Zeyphr/Falcon/Opus/Jasper

V1.0 Xenon:

Bottom of the Board:
Yellow=12v Black=CPU Red=GPU

If your Having Trouble Understanding Click the Picture.

Top of the Board:
Bridge Black for CPU, Bridge Red For GPU.



V2.0 Zephyr, V3.0 Falcon, V4.0 Opus & V5.0 Jasper:
The Zephyr, Falcon, Opus and Jasper Board have the same voltage line to both fans
so it wont be possible to 12 or 7v just one fan w/o cutting the wires.

Bottom of the Board:


Top of the Board:


Note: Sunon and Nidec Fans have Reversed Power Wires.

If you plan to use a potentiometer to manually adjust the fan speed here is one
that is close to the right strength and here is how it should be used.

That looks like a very easy mod to do, as well as a very easy mod to reverse if need be. My system runs very cool now, but I may check that out as well, since it looks like it would be so easy to reverse if I couldn't handle the additional noise.

this is a very easy and safe way to do a 12V mod.

Basically, that transistor connects the fan line to 12V on and off many times a second, creating a voltage on the fan somewhere between 0 and 12v.

Shorting the transistor essentially turns it on 100% of the time, so the fans will be at 12V. It does no damage to the transistor, simply bypasses it.

This will also make your fans work if the transistor is blown (fans don't spin).

Another idea: if you put a potentiometer across the pins of the transistor, then you would be able to control how much you are "boosting" the fan speed. Potentiometer at highest resistance = stock fan speed, as it drops to zero the fans will speed up more and more, until resistance = 0 and the fans are at 12V.

i like this new info. i've been thinking of doing the 12v fan mod for awhile now and now i think i do this one but i have a few questions.

i want to have variable fan speed control using a potentiometer but i have no clue what kind to get. i'm looking at radio shack's web site and there's a bunch of different ones, does it matter what i get?

also, what is a good way/ location to place this potentiometer? i already have one on/off switch for my xcm core cooler mounted in the back and i had to take out some clips that hold the case together to make it work.

Great info guys, thanks!!

Very cool, it's far simpler than mucking about with the fan wires!

Thanks!

a 5 or 1 k would be the best, im not sure you can find a 1k in the huge size, you want it to be as big as possible that way you can mount it inside but have a knob on the outside.

remember you can always cut the ground wires and put them to a 5v source to do the 7v fan mod (except on the v2 and v3 board)

which brings me to the v3 board, i finally got around to modifying the cooling system on a falcon i got in a couple months ago and it turns out if you wire the fans ground to 5v it will throw 0001, also the board is designed differently so the points to solder for 12v are different, if i have time i will take it back apart and take pictures, if not i will get some posted of the next one i get.

I have a falcon board too, so I'll wait for you update. Meanwhile, you think I would safely be able to use "T-tap's" or "12V Case Fan Power Adapter" to do the 12v fan mod? ...both from llama.com, I like the T-tap's thingy but I don't know how well it works...What would u recommend? Thanks in advance!

i did this mod with a 5k potentiometer earlier today. soldering to those points was really hard for me but i did it. it works and all but now how i want it to. turning the nob doesn't do anything until the end. and at the end it shoots up to full power. so there's not too much control. i'm thinking maybe i wires the potentiometer wrong. there's 3 spots on it to solder to. and i soldered the wires to the middle one and one of the outside ones. is that right? i just guessed, i'm not sure why there's 3 points

I didn't understand the pics

Heh, well im guessing a part of the motherboard is zoomed in, its location showed by the little red lines eg. on the top side of the board pic, the middle part is zoomed in and the 4 small red lines shows its location

And you just have to solder the area shown by the thick red line to create the bridge. Please correct me if im wrong though cause im a noob

A nice detailed tutorial of this mod for all the n00bz here would be awesome!...

don't use t-taps, if you really want to do it right now there's a big mosfet right around the same spot on the underside, just wire one of the legs to the head.


if you want more control put the middle leg to the right side of the onboard transistor and get 12v and 5v from under the power connector that way you should be able to use the pet to go from 5v all the way to 12v.

Update
Added: v3 Falcon, Simple 7v.


Dose anyone have high rez pix of the V2 Zephyr?

I don't know if anyone else has had the same results as I did with this mod, but I thought it might be worth mentioning. I was upgrading a friend's 360 for increased cooling and tried this method. The result was not what I expected. While I could tell that there was an increase in the speed of the fans, they still weren't close to what my 360's fan output is by cutting the wires and tapping into the 12V on the mobo. I went back in, removed the jumper, cut the brown and red wires on the fan, soldered to the 12V spot on the mobo and the fans were NOTICEABLY faster with a greater amount of output. Before, the intake grille would barely hold a 3" square piece of paper. After cutting the wires, you could hold the piece of paper about 1/4" from the grille and it would suck to it.

Maybe something wasn't quite right with the contact points on this unit (never RLOD'd newer unit) but I don't think this would be as effective as cutting the wires. Just my $0.02 worth.

that could be caused by 1 of 3 things, there different brands of fans, there isn't a good enough connection on the bridge or the amperage allowed by the controller isn't what it would be from your other source.

it would be easy to test if you have a multi meter.

The fan used was a stock 360 fan (of course, who knows if ONE manufacturer is used throughout). I know that I had an excellent connection on the bridge (I used to solder modchips on PS1s, so I'm used to finite soldering), so I don't think that this was the issue. I'd have to venture a guess that your third option was the issue. I didn't bother testing it out, as I knew the wire-cutting method worked.

Believe me, I'm not knocking the method outlined here...I just wanted others to know about the potential for less than perfect performance when doing this version of the 12V mod.

Thanks for the tut, just done this mod! I added a switch becuase 12V is way too loud when just watching a movie or listening to music.

I have a small question...

I just did the mod on the transistor on the top of the motherboard (V1), as i have done the x-clamp mod and didn't want to take the whole thing out. Only my GPU fan is running at 12V, the CPU fan remains at 5V. Is the CPU fan controlled by the transistor on the underside of the mobo??

Sorry to double post, but I have another question...

After doing the mod, are the fans actually running at 12V or 17V (12V + 5V)?? Only one of my fans is modded (as explained in previous post), and I have cut out the mesh in the back of the metal chassis and the case, yet it is still painfully loud. My other 360 has both the fans modded to 12V (wires cut) and the mesh is still in place, yet it is nowhere near as loud as the one I have modded today.

Any ideas?
Thanks in advance.

It seems like this is true. I just tried it and just with the one on the top of the v1 mobo just the GPU side was at 12v. I also divided the fan shroud. I left it this way to cut down on noise level.

i believe there's 5 different brands of fans that are in the 360, delta (the best and loudest), sunon (crap) and nidec (really crap, but are the quietest) are the ones i have here.

so i tested it and you guys where right, the points to bridge on top will only 12v the gpu fan (and the point under the board is the opposite), i will update the tut with the other bridges for both top and bottom.

Update:
Added: CPU points to the top and "Both" Points to the bottom of V1 Xenon.

Thanks for the update. I had finished up the GPU bridge and was about to put it back together. I decided to check this thread one more time and you had updated it to include the CPU as well.

It works great. Thanks again.

Edit: btw, I have the delta fans. Yes, they are very loud. Oh well, I can deal with that. This, along with the fan shroud mod "should" keep it running cooler. A little extra noise to insure extra cooling won't kill me, or my kids.

i never knew each fan had its own controller but it looks like that's the case on the falcon aswell, i believe the top point is CPU and im not sure about the bottom, i will have to wait until i get my next one in to find out.

So if I am reading you right this is the way to wire the pot or not?



Or am I missing something?

Would not let me edit.

Or does the unused pin on the pot need to be jumpered to the middle leg on the pot? I am a little confused.

Never Mind

Me and my dumb ass did not read the post correctly. I see now what you meant. The only thing that I am unsure about is the jumper shown in the below pic. Does it need to be jumpered at all since the Line-In will supply the voltage coming from the Pot? My guess is it does not, but I would like some input on this before I do the wiring.





Could a Mod please delete my two posts above this, I don't want to confuse anyone.

Thanks,
HoBoZ

that would supply the fans with 12v all the time and the pot wouldn't do anything, you where on the right track the first time its just the middle pin or you can use the head.

edit:
p.s. still connect the 12v to the other side of the pot so you can go from 5v to 12v in one turn.
p.s.s. you can get the 12v from the pin on the right side and the 5v from pin 12 under the back usb port or the left side of the surface mount capacitor in front of the CPU.

So you are saying that my 2nd pic is right? But leave the jumper on the transitor? I am getting a little confused. Could you perhaps draw me a pic.

i suck at diagrams but this is what you need to do;

Thanks, It makes sense now. :

I guess I am just dense sometimes.

This is based off of Grim187's pic, I just added some text.

Note: This is for the GPU only. And it is one a V-1 board.




BTW... Thanks Grim187 for all the help and patience.

Does anyone know if this mod can be done on a zephyr?I want to 12v both fans, but i dont want to do this from the bottom side of the board, must be topside.

Thanks

im pretty sure it can be done on a zephyr i just don't have one to find the points, if/when i get another one in i will check points and take pictures.

if you want me to do the 12v fan mod on it i can for $5 and i would throw in the heatsinks upgrade for free, that way i could post the points for other people.

Thats ok grim187 im perfectly capable of doing the mod, Im just not sure i wanted to risk going by the falcon diagram and blowing transistors,caps,or resistors if something is slightly different.Heres a pic of my zephyr's fan connector area.It looks to be the same as the falcon, but maybe you can take a look at it, and see if theres anything different.I have a multimeter so if you see any points you want me to test to make sure, let me know.




Sorry about all the clutter in the pic.I didnt want to remove the WC tubing and temp probes.

Grim, what do you mean by heatsink upgrade?

I would assume that he means lapping the heatsinks.

chipD: ya that looks the same, i believe that's just the CPU tho. you can test the right side of that transistor to see if its 12v.

RobotBoy: i lap the heatsinks to 2000, reapply them with AS5 and i also put a piece of light cardboard over the gpu heatsink and in the case of a v2 or v3 board i would bend the arm of the gpu heatsink so more air would flow thru it.

So on the falcon diagram bridging the transistor on the topside only runs the cpu fan at 12v? So the transistor on the bottom is for the gpu fan or is that for the cpu fan also?

Im just trying to decide if its really worth the extra work to bridge the transistor on the bottom side.

i have another falcon coming in soon, just give me a week or so and i will update it.

Grim187, are you sure bridging the topside transistor only 12 volts the cpu fan on the falcon board? I took the risk and bridged the transistor on my zephyr, and i swear both fans are running @ 12 volts.It even feels like the gpu side fan is flowing more air....weird.

no im not %100 sure but they are controlled independently so they should be on different circuits.

edit: the top side 12v's both the fans where the bottom side only 12v's the CPU fan, i will try to find a spot to just 12v the gpu fan.

well i just tried to do this on a V2 using the V3 diagram and its caused a few problems.

at first it all seemed ok, then after i put it all back together and tested it out, only GPU fan was working, and then the GPU fan died while it was running.

ive looked at all connections and it all seems ok

EDIT: i just realised that they work fine on 12V but will not run off 5V (i hooked it up to a switch which i tested first

Thats what i thought, I knew i wasnt just imagining things.

Thanks man.Definitly an easy mod.

ok i have xenon motherboard...and im referring to the bottom of the board pic

do i have to solder both bridge to make the cpu+gpu fan run 12v or just one of them (that stated 'Both = GPU + CPU')?

wire from the right leg of the transistor to "both".

Since we cant directly 7v the fans on zephyr and falcon boards, what would be the safest way to do the 12v transistor bridge, then reduce the 12v to somewhere between 7v-9v? Basicly since im liquid cooling my 360, my temps never reach a point where the fans would normally speed up, but i want to get my inside temps as low as i can without making my 360 too loud.At 12v the inside temps of my 360 never get more then 3.5c over room temp, which is really good, but as ive said its just way too loud.Im thinking either 7v or 9v will still give me good air flow without being too loud.Im just not sure what would be the safest way to go about this. Should i just wire a pot inbetween the fan header and fan, or is there a better safer way? It doesnt need to be adjustable since i dont want to drill anymore holes in the case (i have enough already with the tubing and temp probes).

Great mod Grim, I've used it about 6 times already on xenon boards to cool the GPU heatsink. However, today I realised that Sunon fans are wired opposite to Delta fans and bridging the topside GPU points results in a 12v CPU fan.

The plugs are wired the same but the wires go to different fans.

Don't know if this has been pointed out already but thought it was worth a mention.

It could also be a factor with other fans.

My Talismoons are the same as Delta fans.

you could put a bathtub 5watt (the actual wattage is about 3-4watts) resistor on it 10-15 ohms should get it about 7v.


alright well im just gonna put this out there, Sunon and Nidec fans are complete crap, i have seen 360s go 3rlod in 2 months with either of those fans where the ones with delta's last up to 3yrs.

the very best (fitted) fans you can have in your 360 is delta. (this includes talismoon)

p.s. thanks for pointing out another one of m$'s mistakes.

How do you know Delta systems can last 3 years? The 360 has only been out for just over 2.

I've de-X-clamped LOTS of dead delta systems.

I do agree that they are the best fans though.