Modding fans on Q-Tec PSU

owain_thomas · Post by **owain_thomas** » Mon May 19, 2003 2:30 am

I've tried searching for this but without much luck, can anyone point me in the direction of the following info?

1) What is the best way to replace the two noisy fans in the Q-Tec 550W PSU? swap for two new ones, swap for one new one and cover/don't cover the intake?

2) How do you undervolt PSU fans? I've made up the 12v-->7v/5v cable to convert the case fan I have (from a standard molex plug), but how do you do a similar thing to PSU fans? If any one has a link to a detailed guide with photos (I respond well to simple visual explanations

) that'd be great.

Thanks,
Owain

Shuriken · Post by **Shuriken** » Mon May 19, 2003 3:24 am

rant

I still don't understand why people buy Qtec PSU's. They are just utter crap. I have heart of so many people with troubles. And i must say i am not surprised. The prices these PSU's are sold for are just so low it must be made of B quality components.

/rant

If you want to run it on 7 Volt connect the ground wire to +5 V.

owain_thomas · Post by **owain_thomas** » Mon May 19, 2003 4:01 am

Hi shuriken,

I bought the QTec presicely because they are so cheap, it's for my main pc not my planned HTPC so it didn't need to be silent. I needed a new PSU, like NOW, this was the best value I could find.

Any way since then I've been reading a bit and discovered that plenty of people have modded them with a lot of success so I thought I'd try and find out how.

When you say "connect the ground wire to +5v" do you know of any sites that show the layout of these things inside, I've not opened mine up yet and I'm not sure how the fan actually connects to the power, is it a plug like the CPU fan or is it soldered? Any websites with in depth instructions on this?

Cheers
Owain

Shuriken · Post by **Shuriken** » Mon May 19, 2003 4:34 am

I have no idea if it is on a plug or soldered. I never dared buying one. But considering it is so cheapo it will probably be soldered

owain_thomas · Post by **owain_thomas** » Mon May 19, 2003 5:19 am

Ok, I've found out that it has plugs instead of being soldered, so how do I go about undervolting the fans?

Owain

PS thanks for replying even though you obviously have deep, deep issues with this PSU

Shuriken · Post by **Shuriken** » Mon May 19, 2003 6:24 am

Unconnect the black wire from the plug. Then solder it on +5V.

owain_thomas · Post by **owain_thomas** » Mon May 19, 2003 6:26 am

As you've probably guessed I'm a bit of a newb to this, what do you mean when you say "solder it on +5v"? where is the +5v that I need to solder it onto? on the pcb of the PSU?

Thanks
Owain

Will35 · Post by **Will35** » Mon May 19, 2003 6:35 am

You might want to give THIS THREAD a look before you go cutting and soldering. 7v is not the hot setup from what I've read. If you must have 7v buy some resistors or put a pot in the fan line. You might want to spend some time reading the past posts in the Power Supply fourms, you'll come up with many good ideas. Just remember to lean to the safe side when you're messing around w/ your PSU!

owain_thomas · Post by **owain_thomas** » Mon May 19, 2003 6:46 am

OK, what I am trying to understand is this:

If I want to undervolt a PSU fan where do I connect it to get the 7v? Do I have to run wires outside the PSU and have it come from one of the 4 pin molex plugs or is there a way to do it all inside the PSU? If it can be done inside the PSU what needs to be done, is it as simple as the 12v-->7v trick with molex plugs that I've done to my case fan or does it take more effort and soldering etc. to do?

Owain