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Lazy 3.3v rail in PSU

F

Feizy

Joined
Jun 25, 2008
Messages
381 (0.06/day)
Location
Dallas, TX
Hey guys,

I started to experience random shutdowns while gaming and noticed my 3.3v line started to lag a bit and dip below 3.0v. The PSU is a Coolermaster 1000w Silent Pro (not the new M2). I was monitoring the voltage with the ASUS probe software. Anyway, I have since replaced the PSU and the issue has gone away.

So, I still have my old PSU with the lazy 3.3v rail and I was wondering if it would be possible to fix it? Maybe a particular component is to blame and if so which one? Pic of the inside of the PSU is below. Any idea where to start looking?

IMAG0336.jpg
 
I think you'd be better off asking about this in a tech-forum (as in fixing electronics) like the badcaps.net forums.

If the PSU guys on there can't help you, you're pretty much out of luck.
Some of the people on there rebuilt PSUs that blew up (spectacularly) because of being overloaded.. just to give you an idea of what tech level we're talking here ;)
 
Feizy said:
Hey guys,

I started to experience random shutdowns while gaming and noticed my 3.3v line started to lag a bit and dip below 3.0v. The PSU is a Coolermaster 1000w Silent Pro (not the new M2). I was monitoring the voltage with the ASUS probe software. Anyway, I have since replaced the PSU and the issue has gone away.

So, I still have my old PSU with the lazy 3.3v rail and I was wondering if it would be possible to fix it? Maybe a particular component is to blame and if so which one? Pic of the inside of the PSU is below. Any idea where to start looking?

http://img.techpowerup.org/120322/IMAG0336.jpg
Click to expand...

Don't touch the Caps n coils .. SZZZZEEETTttt crispy.
 
^ totally pointless comment.
 
Bo$$ said:
very useful, those caps can still hold charge!!
Click to expand...

Eh, not necessarily. On 99% of the ATX computers I own, the 5VSB rail will keep running for a few seconds after I unplug the power from the wall until there is no longer a sufficient amount of electricity in the primary capacitors.

On things such as microwaves and CRT monitors, yes, those can be super dangerous and even lethal. A generally good idea to discharge those devices is to have them running and then suddenly unplug them from the wall. That should dissipate a lot of the current that may have been stored if you unplugged the device while it was turned off and not consuming any current.
 
The only capacitors which could potentially hurt you in an ATX PSU are the primaries (one in this case.. the 400+V rated grain silo in the bottom left). The others are too low voltage/capacitance to cause any harm.

That ain't gonna happen in 99% of the cases though because all quality ATX PSUs (i.e. not 15$ china firecrackers) I've seen so far had a bleeder resistor across the primary cap(s) to discharge them within seconds after unplugging the unit from the mains.

If you want to be 110% sure, short the pins of the primary cap(s) with a screwdriver with an insulated handle. Usually nothing should happen if you do that. Be prepared for a "pop" though in case there is actually some charge left.

Should be obvious you shouldn't be in there while it's powered up / plugged in.
Any why he mentioned the coils.. no idea. He doesn't seem to have any clue about what he's talking apart from "electricity = danger" :wtf:
 
Bambooz said:
^ totally pointless comment.
Click to expand...
lol appears not... lol fail... it was more or less a joke but... it's funny how you say nothing can happen yet in the same paragraph.. be prepared for a "pop" if there is some charge left... dude wats wrong, you got something against warning people about possible charge??

Bo$$ said:
very useful, those caps can still hold charge!!
Click to expand...

Thank you Bo$$ I think warning people just against sudden jolts incase they are not aware is a good idea too.



_____________________________________________________
Decades old CPUs won't impress me... well, maybe if I was in Europe lol.
 
Last edited:
All/most of the secondary caps in that unit are Rubycon.. Very nice caps and I wouldn't think they are the culprit. My knowledge is limited, but it seems as if the coil on the bottom right of the picture is the 3.3v coil and that would be the first place I would look for the issue. Before replacing parts, it would be a good idea to get out the multimeter and actually check how it's doing.

VV cmaris would definitely know.. Alot more than myself.
 
Perhaps a PM to crmaris here on TPU for some help.

He is the guy who reviews the PSU's here on TPU.

Maybe he has reviewed your model and you could gleem some information from comments and pictures.

http://www.techpowerup.com/reviews/?category=Power Supplies
 
Some posts cleaned. Stay on topic.
 
Keep it civil gentlemen.
 
erocker said:
All/most of the secondary caps in that unit are Rubycon.. Very nice caps and I wouldn't think they are the culprit.
Click to expand...
Rubycons are indeed good caps, but there are none in this PSU. Nippon Chemicon instead, which aren't any worse.
 
Bambooz said:
Rubycons are indeed good caps, but there are none in this PSU. Nippon Chemicon instead, which aren't any worse.
Click to expand...

The main cap is Nippon Chemicon, I'm pretty sure the others are Rubycon.
 
Also, try and measure your voltages through a multi meter, the software can sometimes be quite far out on the minor rails. If the PSU is old it would be an idea to recap it, i'm no expert but Capactor aging will cause those random shutdowns you are having
 
Bo$$ said:
Also, try and measure your voltages through a multi meter, the software can sometimes be quite far out on the minor rails. If the PSU is old it would be an idea to recap it, i'm no expert but Capactor aging will cause those random shutdowns you are having
Click to expand...

The PSU is no more than a year old, I will update everyone next week when I start poking around inside the PSU. The volt-meter is at my work.
 
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