Chieftec 1200w 12v rails

M

martinlink

n00b
Joined
Nov 14, 2011
Messages
10
Hey peeps, long time lurker here.
I have a 2 year 6 month old Chieftec Super Series 1200W PSU which is giving me some trouble with its 12v rails.
In BIOS I'm getting 11,368v, in Everest and HWMonitor I'm getting 11,59v with fluctuations down to 11,54 at idle.
BUT: When I power on some game which sucks juice from the GPU (HD6950 unlocked to 6970) it drops right down to 11,20v. With OCCT Linpack, it drops to 10,8 in like 5 seconds at which point I instinctively shut the test off in fear of the machine going Boom or something.

The PSU suffered a fault in the fan controller and I had a technician fix it. He said he got 12v stable out of it with his test computer (with a power draw of 300W max) last week. So why am I getting these low volts on mine? The fans work perfectly now, by the way.
Might this be dangerous to the PC?

By the way, thinking that only one 12v rail is underpowered (dunno how this stuff really works tho), I swapped the PCI-e cable's location in the PSU's holes (it's modular) - no change whatsoever. Tried a total of 4 combinations to no avail. Still sitting at 11,368v in BIOS. SO tried removing 2 of the 3 fans in the case and still the same story. (2x6pin PCI-e holes on the GPU).

HELP please! What could I try next, or is this even such a big problem?
If I had a multimeter, I'd try testing the rails mechanically as software might be off with the measurements, but I don't have one. The technician said both his BIOS and multimeter showed 12v more or less.
 
Last edited:
time to buy a new one :D

no but for real, I think it's either the voltage sensor returning offset values, or your best bet is to RMA it since most psu has more than 2 years warranty
 
Lol not this one, not now at least, since it has been opened upwards of 9000 times :p
But is it then not possible that with a weaker PC it gets the full 12v but with my machine it can't get enough juice for 12v and only goes up to 11,4 or so...?
 
martinlink said:
Lol not this one, not now at least, since it has been opened upwards of 9000 times :p
But is it then not possible that with a weaker PC it gets the full 12v but with my machine it can't get enough juice for 12v and only goes up to 11,4 or so...?
Click to expand...

You will never know the answer to your question unless you go out and buy a multi-meter. BIOS readings and software readings are notoriously wrong, always have been and probably always will be wrong.

Spend the $15 to $25 bucks and get some real readings before you condemn the PSU.

If you read down this forum or use forum search this has come up more times than the old “What PSU is Best” question:)
 
Software readings will never be reliable or accurate. You need a multimeter. There is no argument here, do not try to argue otherwise.

Edit: The fact that your computer continued functioning when the voltage supposedly dropped below 11.5v is testament to its inaccuracy. Computers are designed to function between 11.5 and 12.5v only, and are supposed to shut down automatically if it goes out of spec.
 
Alright, bringing this one up again as I seem to be having problems with the PSU yet again.
The supply worked alright until like a week ago (still low voltages but no crashes or freezes whatsoever...).
Then, after I had messed up with replacing one of my fans (the blades were hitting a part of the PC case) I tried to turn the machine off from the on-off button immediately, but it didn't respond until it had loaded up windows. It then shut off when I kept pressing the button, after which I flipped the switch on the PSU and corrected the fan issue, I flipped the PSU back on and tried to power the machine on but absolutely nothing happened - the fans didn't spin up or anything. I also noticed that the green LED on the motherboard wasn't on. I reconnected every cable from the PSU and tried replacing the PSU power cord, and waiting ~20 minutes before trying to turn it on again, to no avail.
So I left the PC with the PSU switched off for like 3 hours and when I come home I flip the PSU on again and see the green LED lighting up on the mobo. The PC turns on perfectly and everything is working like it was before the fan accident.

Questions: Why didn't the PSU work after it had been shut down suddenly (after running for like 1 minute max)? Why did it start working again after 3 hours, but not after 20 minutes...? Might there have been some overheating issues? The PSU has a 140mm and 80mm fan which were both working when I turned it on in the beginning. The voltages are still low in BIOS and HWMonitor.


P.S. thinking about the Seasonic 1000W Platinum to end this once and for all, I'm so fed up with this PSU already, lol. But still would like to know what the cause of this nonsense is and keep using it until I get the money for the Seasonic (student life is meh...)
 
The PSU has nothing to do with power button behavior. That is a BIOS function of the moterboard.

To check if the PSU powers up on command jump the green wires in the 20/24 pin ATX plug to a black ground with a paper clip. PSU should turn on. If it does look at your motherboard, not the PSU. Buying a new PSU will change nothing here.

You've been advised multiple times to check voltages with a multimeter. If you're just looking for an excuse to buy a new toy then say so otherwise accept the fact that software voltage readings are meaningless.

EDIT: relevant link http://dodji.seketeli.com/downloads/shuttle-psu-paper-clip-test.pdf
 
I am, at least for the moment, not looking at the voltages at all - leave them be as they are, I will test them eventually when I have the time.
But the matter at hand is the weird behaviour of the PSU after a "freak shutdown" where it delivers absolutely no power to the motherboard. The motherboard and all other components were tested with another PSU (Hiper 880W) and were proven working.

I did the paper clip trick when the PSU first failed (before the technician fixing the fan controller in the PSU - see first post) and it didn't work. After the failure 1 week ago, I didn't think about doing the paper clip trick :( I'll keep it in mind and when it does this again, I'll try it.

But anyway, still would like to know what could cause this kind of behaviour - PC does not turn on after 20 minutes of waiting but turns on after 3 hours...
 
If the paper clip jumper doesn't power up the PSU then I think you are rightly suspicious of it. RMA time.

There are all manner of components that will fail if overheated. Just because a fan is running doesn't mean something hasn't failed inside.
 
As I mentioned before, it has no more warranty left...
Yesterday evening the pc did it again when i tried to turn it on. So i jumped it with a paperclip and as expected, nothing happened. I left it until today, tried to jump it and it worked. So i put the pc together again and everything works like yesterday.
But for how long...? What might be causing this, after all?
Thanks for the input thus far!
 
You must log in or register to reply here.
Back
Top