Which line is the 5v sense line in an ATX PS?

[Lmandrake]

I would like to trick my ATX ps into thinking that its 5v output is less than it really is. I have heard of a hack where insertion of a schottky diode in the 5v sense line can fool the PS power regulation circuit into over-compensating the 5v and pumping out more 5v power.

There are, unfortunately, a number of 5v lines connected to the mobo and determining which is the line used by the PS to sense (if it is only one and not all of them) is difficult to discern without a schematic or sufficient info from the MFR.

Anybody got any ideas?

Thanks

 

[Demon-Xanth]

I believe that is done within the power supply itself

 

[RossGr]

I did a search on ATX formfactor. Open the pdf at the bottom of this page. It has the info you need.

I cannot belive that you scheme will improve the performance of your system.

 

[Evadman]

If your PWS 5v rail drops below 5, that means it has no more to put out. The way power supplies are made, you can not just pull wattage from the 12v line, and put it into the 5v line.

Yes it is simplifing, but it is close enough 🙂

 

[Mark R]

Unfortunately, ATX does not provide for remote sensing of the 5V line. This is quite a limitiation, and would overcome the problems that people are having with motherboards with poor power circuits (e.g. Epox). The latest ATX extension specifies an optional connector with a remote sense for the 3.3 V line, where voltage drops are more important.

The sensing is done within the supply, although most will extend the sense wire to the PSU end of the ATX connector - it will attach to one of the 5V pins in the connector, and will be of a lighter guage than the current carrying wires.