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How would i mod the 12 and 5 volt rails on FSP400-60PFN

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Jklipper

Registered
Joined
Mar 10, 2004
Location
Canada
How would i mod the 12 and 5 volt rails on FSP400-60PFN. It has a vsense line on the 3.3 and looks pretty easy to do with a guide in the forum :) , but none on the other 2. Here are some specs below i got from Newegg if they might help.

I want to do these mods to see if i can stablize my voltages a bit, 12 volt is 11.68-11.48 and 5 volt seemspretty stable at 5 sometimes dropping. My 3.3 seems to sit around 3.26-3.28. I took these readings from Hardware Doctor on my Infinity

Model# FSP400-60PFN RET
Specifications:
Type: ATX
Maximum Power: 400W
PFC: Active
Power Good Signal: 100-500ms
Hold-up Time: 17ms min.
Efficiency: Min 65%,Typical 70% (at full load)
Over Voltage Protection: +5V ; +3.3V ; +12V
Overload Protection: Not specified
Input Voltage: 100-240 VAC Full Range
Input Frequency Range: 47Hz-63Hz
Input Current: 5A
Output: [email protected];[email protected];[email protected];[email protected];[email protected];[email protected]
 

pelikan

Member
Joined
Jan 22, 2003
There should be some pots inside that you can turn to set the voltage. Most FSP's have a single pot that adjusts both the 5V and 12V at the same time. When you adjust the pot, use a DMM to read from a molex while the psu is under load. I run prime95 while adjusting my psu.
Just in case you don't know, it is not a good idea to rely on sofware voltage monitoring when adjusting voltages.
 

FIZZ3

Member
Joined
Jun 27, 2002
Location
NL, Europe
Don't sail by software voltage readouts. The reported values are an interpretation that requires 'calibration parameters' that are not specified and subject to bias. The readings can be off by a lot with no way of knowing in which direction and how much.
Furthermore, mainboard readings (as interpreted by software or measured directly) reflect the operation of the board itself- not the pure output of the power supply.
For best results you should measure the power supply lines with a multimeter and correct output from there. Even if you would want to compensate for weak mainboard transfer you would still need to measure the voltages on your own. Note that mainboard-induced line regulation variability is impossible to correct except by crudely overvolting so that the minimum value is in an acceptable range. Good luck.
 
OP
Jklipper

Jklipper

Registered
Joined
Mar 10, 2004
Location
Canada
What do you think would be a safe affective voltage to give my Infinity or any other board to compensate for weak mainboard transfer? I am hoping to give it a bit more stability while Priming. One time i can prime for over an hour at 251fsb, 3.3 to ram. All of a sudden i can't prime for more than a few minutes. I would like to start here with the PSU before trying any other mods to my board. With a multimeter i get 5.15 on 5v and 11.94 on 12v.
 

pelikan

Member
Joined
Jan 22, 2003
I've raised my rails to 3.4, 5.25 and 12.4 but didn't notice any difference. I don't think it helps. But it is fun to adjust them and to know that they are high enough.
 
OP
Jklipper

Jklipper

Registered
Joined
Mar 10, 2004
Location
Canada
Well this psu does have a pot to increase the 5 and 12. I set it to 5.4 and 12.6 and it doesn't seem to help. Think i will leave it for now and see how it goes. Thanks guys
 

larrymoencurly

Member
Joined
Jul 14, 2002
How do you know that your rails are weak? I've learned not to trust motherboard monitoring hardware at all, not even for fluctuations in voltage (more than once, it showed fluctuations while my meter didn't budge at all, not even its bar graph display, which responds a lot faster than the digit display).

When you adjust the rails, be sure that the power supply is plugged into an outlet that's GFCI protected, to reduce your odds of being electrocuted (i.e., killed by electricity). A GFCI is a shock prevention device, not a circuit breaker, and homes built in the past 20-25 years in the U.S. have been required to have only GFCI-protected outlets in the kitchen, bathroom, and outdoors (including garage). A GFCI outlet costs less than $10, and there are plug-in GFCI that are about as cheap. Also don't use a regular screwdriver but one made entirely of fiberglass or plastic. Radio Shack and electronics supplies sell them as tuning wands, but you may be able to get by with a chopstick if you carve its tip. There's a lot of exposed high voltage in side any PSU, often right next to the low voltage areas, and with some PSUs even the heatsink may have high voltage on it. I haven't seen that in a Fortron but I have in Enermax, Antec (Channel Well), Delta (AKA Acer) and Powmax (Leadman/Raidmax/Robanton) PSUs.