5V mod for QTEC 550W psu?

[Stinger666]

The 5V/12V mod doesnt simply work with a 100K pot? I used it and the only sound my PSU made was a sissling sound from the mosfets...

[fr33ze]

Originally posted by Stinger666
The 5V/12V mod doesnt simply work with a 100K pot? I used it and the only sound my PSU made was a sissling sound from the mosfets...

thats a bit worrying, did you definately connect it to the right pin of the ic and the right legs on the pot, all i used was a pot and it worked fine

[Stinger666]

Originally posted by fr33ze
thats a bit worrying, did you definately connect it to the right pin of the ic and the right legs on the pot, all i used was a pot and it worked fine

Yes I did connect PIN 1 of the TL494CN to a 100KOhm variable resistor and to a 'ground'pin (actually the 'ground' lines on the PSU itself)

Probably I got the wrong pot, need to have a more heavy one I think! (The one I use is a small rectangle, blue, gives about 20 turns and is very small. (Probably I need a very big turningpot/ trimmer...

[mongoled]

Same problem here as Stinger666, connected as in diagram, get a short (sizzling sound).

Maybe these newer qtec are different, anyone got any other links to 12/5v qtec rail mod??

[Tilmitt]

Hey i have a 450W q-tec dual fan psu and after examining it i have found the "IC2" on which pin one needs to be connected to ground. Also i think the place i have marked ground is connected directly to ground so i'd say i could use that. Only thing is IC2 is almost impossible to get at, how could you guys solder a 100k resister to it?

[mongoled]

Look at where the pin comes through the back of the pcb and solder your resistor to that

I hope thats what u mean solution just seems to easy???

[Tilmitt]

Ok thanks i'll give it a try.

[Rub87]

Hi,

I've read some stuff about voltmodding this baby..

My voltline are very stable and relative high, 5V rail is always over 5V with cpu @ 3Ghz full load (NF7-s)

12v is also ok..

but 3.3v is around 3.30-3.36 under idle and doesn't actually change much under load, I use 2*512 BH5 with Vdimm connected to +3.3v..

I'm stuck @ 240*12 wich give me 35 sec super pi..

I really want those 34s so I want some more juice for the BH-5, lets say 3.5-3.6v..

Which was does really work?

1

The 3.3v is a done deal I can get that up with a Diode on
the 3.3v sense and a resistor change on the board

Replace R28 with 10 Ohm..?

2

Its CP431 which control 3.3V feedback lines. You put 10K VR in parallel to R56 ( blue resistor located between CP431 and black wires ). Slowly turn the VR to lower resistance, and you will see the 3.3V line goes up !!!

Thx in advance!

[Rub87]

Anyone?