Why is my 5V so low? Read this

[khaos]

watch out for extreme low voltages, my 350 enermax was running a 5v line of 4.5v, and i get 1/2 melted 5v wires in the ATX cable and the ATX connector gets fused to my mobo, ruining it.

Now the first thing out of everyones mouth is going to be "YOU OVERLOADED THE PSU !," however this is not the case. If i did infact overload it, and overload protection circuit in the PSU would have been tripped and no damage would have been done.

My specualtion is that the mobo started drawing more amps because of the lack of voltage. It coudn't even run folding without crash. Also, the system was at stock speed at the time, since i was having some trouble with voltages running at 1500.

YOU OVERLOADED THE PSU !

Just kidding. What I believe happened is that your ATX connector became oxidized or the connections were simply poor, resulting in a whole lot of power with nowhere to go. This explains both symptoms: Your low voltage and your melted ATX power connector. How many pins burned out/melted? I would imagine it was only one or two since your +5V voltage was not abysmal... Just pretty bad.

This is also my first post here, so... Hello everybody. I post over @ Icrontic and my attention was drawn to the article by a newer article, etc. etc. Great job on the article Hoot. I'm employing it somewhat, but going to solder the inductor to the capacitors that are before the MOSFETS in order to minimize line noise on the +5V.

 

[!-=sky=-!]

ummm.....
how would you do this on a epox 8kha board........

i m..running 4.5x on my 5v rail line with a enermax 451watt psu

i dont have access to a voltmeter at the moment but i think i hsould buy one

thx

btw my computer setup is

t-bird 1ghz running at 1472 (9.5x155)

with

quantum fireball lm 30gb 7200rpm hdd
elsa geforce2 pro 64mb ddr video card
winfast 6x sound card
8 case fans
creative infra cdrom and an old hp cd writer

 

[packratbob]

ummm.....
how would you do this on a epox 8kha board........

i m..running 4.5x on my 5v rail line with a enermax 451watt psu

i dont have access to a voltmeter at the moment but i think i hsould buy one

thx

btw my computer setup is

t-bird 1ghz running at 1472 (9.5x155)

with

quantum fireball lm 30gb 7200rpm hdd
elsa geforce2 pro 64mb ddr video card
winfast 6x sound card
8 case fans
creative infra cdrom and an old hp cd writer

woah 4.5 is pretty low man!! and isn't it cosing u stability problems??

 

[Loud]

Sky - I think the general opinion is that Enermax is not the high quality PSU it once was. From the posts I read pretty regularly, this sort of sag is almost expected.

You might try a different (better) PSU. Personally, I love the Antec I'm running. There are several brands suggested in other topics within this forum.

 

[!-=sky=-!]

woah 4.5 is pretty low man!! and isn't it cosing u stability problems??

no....for some reason my computer is STILL runnning fine


also, since i live in hong kong i dont have as much selection of hardware as people in other countries do....and...i dont have money...haha

thx for the replies..but....i m still wondering on how to do this mod
i dont get most of the stuff in the article

 

[Yobbzz]

Can someone please poast a pic of the right Mosfets to use on the Abit KR7A raid.

 

[IceMan3928]

what do you guys consider low? according to ASUS PC probe my 5v line is 4.919, is that ok?

 

[eobard]

I didn't have problems with my old power supply until the 5v dropped below 4.83v. Depending on what you have in the system, 4.91v should be fine.

 

[flyfisher]

My ps is only putting out 4.85v. Is there someway to connect this wire from the mofsets to the 12v line with a rheostat or potentiometer or something and adjust the 12v down to a GOOD 5.0v?
Did the mod and it worked great, voltage went up from 4.74v to the 4.85v the ps is kickin out, am now able to run at 160fsb, up from 146 max before!

HOOTIE HOOT

 

[splat]

check out my psu stats...they suck don't they....300w fsb group

stats in this post.. http://forum.oc-forums.com/vb/showthread.php?threadid=96451

 

[JFettig]

anyone done this on a 8k3a? because im interested in knowing what ones it is so i dont have to take the time to figure out what ones it is...

 

[JFettig]

i did it!
its the 3 mosfets on the front of the board, now at stock voltage i get 4.99v, and at 2.2v i get 4.92, and my voltages dont move a bit...

 

[JFettig]

well i had a huge scare, and it seems noone is reading this, but one of cords came off the center fet, and almost fried my board....

 

[The Coolest]

Hey hoot, I had a thought, if your PSU isn't powerfull enough on the 5V rail then why not use the 12V? Just connect the +12V to a "converter" (forgot how its on english) to 5V and u'll be getting a constant flow or very stable 5V? Could this work?

 

[freshy98]

Hey hoot, I had a thought, if your PSU isn't powerfull enough on the 5V rail then why not use the 12V? Just connect the +12V to a "converter" (forgot how its on english) to 5V and u'll be getting a constant flow or very stable 5V? Could this work?

Couple of weeks ago that thought was already presented on the main page of overclockers.com. Forgot his name but he used 2 7805's for it.
But it's still a good idea

 

[The Coolest]

Yea, that's what I meant so the converted 5V would be good enough to use in this mod?

 

[freshy98]

yeah, in fact it's even better.
the 7805's compensate when the +5V drops.
so basicelly (yes I know, misspelled) it will always be kept at +5V.

the 7805 draws 12V and converts it to 5V, but never lower than 5V. mind though that you need a big heatsink for the 7805's 'cause they get real hot!!!

 

[The Coolest]

What if I put a little thermal paste and glue them to the top part of the case to use the chassis as a really large heatsink?

 

[freshy98]

What if I put a little thermal paste and glue them to the top part of the case to use the chassis as a really large heatsink?

hehe, I wouldn't do that if I were you!!!
the side connected to the heatsink is also under current.
so putting the back of the 7805 to the case would mean that you put 12V to the case
really, use a heatsink and don't put the heatsink on the case!!!

 

[packratbob]

hehe, I wouldn't do that if I were you!!!
the side connected to the heatsink is also under current.
so putting the back of the 7805 to the case would mean that you put 12V to the case
really, use a heatsink and don't put the heatsink on the case!!!

i thought the back of those were equivalent to the ground??