View Full Version : i have a quick?about powering on psu
hello.this is my 1st post here.i have an antec true power 550,and have assembled all my trimmers and resistors i need.i remember reading somewhere that said when you use the wire trick when turning on the psu when not connected to the the mb,that you should have a load on the psu.like and old cdrom.they were warning that you could fry the psu by not doing this.does anyone do this when turning on the psu,before testing the voltages.
thnx
Reflex1
01-28-2004, 03:31 AM
huh? u put resistors on ur PSU? ...i dont really follow.
but welcome :toast:
enzoR
01-28-2004, 01:26 PM
no... but if you dont your rails will be messed up. all you have to do is put a 5ohm resistor on your 5v rail. i used around 20w and it got well hot. i advidse you to use a higher rating. around 35 or so. you wont fry your psu but your rails will be much lower than normall.
thnx for replies guys.the point of my post is still there.should you not have a load on your psu when starting it up outside the case,or disconnected from the mb.like i said it was in an article i read somewhere that stated you shou;d put a load on the psu,like a cdrom,before starting it up to adjust voltages on the 3,5,or 12volt lines.thnx
Hell-Fire
01-30-2004, 03:46 PM
No, you dont need a load on it...in fact you dont want a load on it right after the mod is done.
Lets say you inadvertently set the resistance to low on the trimmer....now your 12v rail is sitting at something ridiculous like 15v....not sure thats good for anything other than frying it.
Just use the paper clip method to turn it on outside the case. That way since nothing is connected to it, you can check all the voltages and adjust them to whatever levels you desire without having to worry about blowing anything.
I have the same psu and did the mod without a single issue. You will be fine. Just stick a paper clip in the ATX connector on the green wire and any black wire. Then plug it in and flip its power switch. It should fire right up. If it doesnt, you need to unplug it....let the caps discharge before handing it.....then reseat your paper clip and try again.
thnx for reply hellfire.so where on the atx line did you do the mods.at the end by the connector,or by where the cables come out of the psu
Hell-Fire
01-30-2004, 08:49 PM
That part is all about personal preference.
What I did was snip the wires close to where they exit the psu housing. Then I soldered some extra wire to each snipped end that runs to the ATX connector, to add about an extra 3 inches. That way I could run the wires back into the PSU and pull them out one of those slits on the side.
If you decide to do it that way, make sure on the first cut that you allow for enough wire for the wires that are connected to the psu board to be able to come out of the slits beside them so you dont have to add extra wire there as well. If you start at where they exit the psu housing and go down say 1-2 inches, you will have enough wire.
That way after doing your mods you can simply glue them in place.
I dont recommend doing it so that you have to mount the VRs to the ATX bundle as you can rip them off while trying to do something.
Important on this mod that you DO use a fixed resistor inline with the VR or it will not work. After soldering the fixed between where you made your cuts, solder one of the legs from the VR to the "wire" exiting the top of fixed resistor.
I would set the VR to max resistance before soldering in place.
I am redoing mine at the moment since I am rebuilding my entire rig. If you can stand to wait a day or so I will have pics up ifyou prefer that.
yes,some pix of your finished mod would be great.thanks again
Hell-Fire
01-30-2004, 09:09 PM
No worries. Be Sunday at the latest I think.
madsam
02-02-2004, 08:22 AM
Here's a good read on dual-psu's:
http://www.ocforums.com/showthread.php?s=&threadid=88976&perpage=30&pagenumber=1 ;)
and another one with a couple pics in this forum: http://www.xtremesystems.org/forums/showthread.php?s=&threadid=23475 ;)
Hell-Fire
02-02-2004, 02:03 PM
Sorry, havent had time to post pics.
I am on a linux box so uploading pics from my dig camera is a no go for me atm.
Its a very easy mod:
1. Cut sense wires for the volt rails.
2. Solder a fixed resistor between the 2 cut wires. I recommend nothing more than 47ohm.
3. Solder a wire from the top leg of the fixed resistor to the middle leg of the 10k vr.
4. Solder a ground wire to the top leg of the VR, then to any ground point you prefer to use.
**Be sure that the VR is set to max resistance before soldering on.