Artificial Load to mod PSU voltages?

[Jimbo Mahoney]

I have read the guides here re: Sense wires.

However, I am using a Globalwin 520 Super silent which only has a 3.3v sense wire (quite common it seems).

I'm fairly sure I've read somewhere the PSU can be tricked into thinking there is a greater load on a particular line using a high wattage resistor?

Does this make sense to anyone?

If it's possible, it would mean that one could mod a molex extension lead to include a fixed or variable resistor to place an artificial load on the 5v or 12v line. This would be removeable so the PSU could still be RMA'ed ;)

Any thoughts?

[enzoR]

no not possible. you can only do that if there is ZERO load on the other rails and you are using the 12v rail. then you have to put a load on the 5v rail to get the 12v rail up because it will only be at 10v or so. if your PSU has a "Hi pot test OK" sticker on it, you will most likely have pots inside that you can turn to change the rails voltages.

[L337 M33P]

Originally posted by enzoR
no not possible. you can only do that if there is ZERO load on the other rails and you are using the 12v rail. then you have to put a load on the 5v rail to get the 12v rail up because it will only be at 10v or so. if your PSU has a "Hi pot test OK" sticker on it, you will most likely have pots inside that you can turn to change the rails voltages.

Hi-pot test refers to the insulation resistance test. The PSU is subjected to an abnormally high voltage on the input? To test the insulation for flaws that might result in a short to ground.

You CAN load a PSU artificially using resistors, but that wouldn't do anything for your voltages on that rail as the PSU simply tries to output the same voltage under varying current.

You would want to load your 5V or 12V rail because the PSU uses one transformer for both rails. An increase in current draw from one rail (say 5V if your motherboard uses 5V for core voltage) will result in the other rail voltage going up. Loading the 12V rail will push the 5V rail up and vice versa, it's a limitation of a design that uses 1 transformer for 2 voltages.

For instance I have a Fortron 400W PSU and Asus A7N8X motherboard. I tweaked the voltages using an internal pot so they are 12.3V and 5.16V with no load. Loading it with my motherboard which uses 5V results in a 5V voltage of 5.02V and 12V of 12.6V. Sticking a 12 ohm resistor on the 12V line would push my 5V up a bit, but it isn't worth it.

[sjohnson]

Agree with L337 M33P. And enzoR, except for the High Pot reference. There I'm with L337 M33P. High pot means nothing WRT internal trim pots.

[enzoR]

Oh i'm sorry. i read somewhere that that was the case... the pots were checked and set or whatever.. must have been at [H] :rolleyes: now that you explain it to me it makes lots of sense. thanks!!!