Why is my 5V so low? Read this

[mustrum]

I am just wondering how many people this thread has killed or seriously injured

If you have worries about clean power to your system components I recommend two easy steps. Buy a high quality power supply and buy a high quality motherboard..... "You get what you pay for...."

I have an Asus a7n8x Deluxe 2.0 and an enermax 431Watt PSU with extremely decent Amps on the rails.
My 5v rail dips down as low as 4.45v!!!!!!

 

[Doulton]

Hello, So I'm having a unique problem, currently my PSU is 350W, I recently added a Radeon 9800 Pro and my current -12V is at (-13.4)-(-13.5) I understand this is bad considering most people here are freaking out about some small varianences of Voltages. I figure a new PSU is necesary, but could you tell me what uses the -12V ? Thanks...

 

[yanz]

maybe we can make a sticky thread about "Too many of you are too worried about -v rails! "

ok, if -v rails are really used by some device/pc components than i wrong to believe that -v rails are useless in the atx/modern system...

maybe some tech savy people here can explain more details about it...

 

[Tw3ak3d]

Mine used to drop also , I modded the line to stabalize it and a pot to increase it , no it drops no more than .05v ever ..

 

[Banthur]

Will have to try this...

 

[jesse]

Nice, informative guide. Im gunna have to try this.

 

[ochungry]

Aren’t those 5V lines from ATX power go through a series of capacitors(and possibly the chokes) before connecting to the mosfets? and if so, wouldn’t the mosfets encounter increased ripple and noise interferences, that might damage the core regulator, and the caps and resistors interacting with it?
Just wondering. I am seeing a few small caps along the 5V path before connecting to mosfets. I wonder why they are there and what would happen if by passed doing this mod.
Thanks

 

[yanz]

They are there to smoothing the input load for the mosfet (vrm). If they fail on job, mosfet with get an excessive ripple input and it will get hot as its inefficiency rise..

As for the inductor (coil/chokes), they store the energy, and functioning the same as capasitor.

Failing caps on PSU can also make the output ugly, and the mobo will get an excessive input. cmiiw..

Beware of the caps condition in your PSU & motherboard. See this forum : www.badcaps.net/forum

 

[EmAn]

so let me get this all strait

first to test your psu you check an unused molex on the +/-5v lines
then you check on the mosfets using the middle tab and a ground point as close as possible to the mosfet? such as a mounting screw?

then once you find your mosfets that get the +5 you solder the +5 volt wires onto the center tab and that is it
or did i miss something?

 

[Ken B.]

I have a suggestion...

Hi Hoot,

I have a suggestion regarding your original post, here.

Have you heard of this stuff called Stabilant-22?


SUPER CONDUCTOR

"If you've ever had to track down an elusive bad or intermittent connector-a computer card connector, an IC socket or even an RCA jack-Stabilant 22 is for you. The slightly 'goopy' liquid is sparingly brushed onto connectors or IC pins (or whatever) and becomes conductive when 'activated' by an electric current. The manufacturer claims S-22 'provides the reliability of a soldered joint without bonding the contact surfaces together.'

Illustration of bottles of Stabilant 22/22A If you're worried about shorting -out adjacent contacts with this 'liquid conductor,' don't be. S-22 is only conductive across a very narrow gap: The contacts must be in physical proximity for Stabilant 22 to work. (To prove the point, the manufacturer's trade-show-computer, housed in a see-through plastic case, has its mother board totally submerged in S-22!) Winner of Byte Magazine's Product of the Year Award, S-22 has for some time been the audio and broadcast engineer's secret weapon. It's useful from 'dc to daylight,' and one application lasts for several years. S-22 has thousands of uses in Amateur Radio, and is now available from the manufacturer in smaller, more affordable amounts. (Yes, it is expensive, but a small vial will probably last a long time. My miniature sampler vial has already 'tamed' an intermittent RTTY terminal plug-in connector and restored function to a 'potted' RF converter module that would otherwise have been unfixable.) Contact the manufacturer for information and application notes."


http://www.stabilant.com/llsting.htm#rrevv01.htm

I had found about this long ago when a distributor back in the late 80's/90's would dilute it, and repackage it and called it "Tweek". It was sold to the audiophile market. That distributor and product no longer exists, but the real manufacturer does, and apparently they are still selling the stuff mostly to professional industry like auto and emergency medical. You might check it out.