PSU help

[hitman]

I have a Coolmax 1200w PSU that supplies 30a on a 12v rail. My video cards require 36a...however, I have four 12v rails, 2 each for my video cards. Its been a while since I did power calculations, but would my PSU be more than enough to handle my cards? My PSU doesnt have a max amp specification on the label, and Im kind of on the rope in getting a new one. Any ideas?

[Krippz]

Looking at your current configuration a 1200W PSU is more than enough. You are fine for now; video card power consumption is declining not increasing.

[hitman]

Think I may have a problem with my psu...is there a way to test this without a psu tester?

[Kuky]

Hey hitman, the 1200W PSU should be very suficient for your SLI setup. You have 4 PCI-E connectors (2 connectors on 2 12V rails)?

[hitman]

Yes...but it doesnt give me anything. It doesnt even light up the board except briefly. It was working before I installed the last motherboard, it powered up the mobo last time for about 2 minutes. I didnt get anything out of the startup (post, bios, dark screen...), tried to reboot and it would only come on very intermittently. I thought it was the mobo that was DOA. I got the new mobo today and Im geting typical results.

[Kuky]

hm... is your PSU modular with cables that can detach? If so do you possibly have another PSU that's modulear as well? If so double check you didn't mix up the cables from oone PSU with another (happened to me once).

 

My case was that I connected HDD with wrong cable and even though it fits to PSU pinout was wrong. It made my system no boot (with good reason) bu since I didn't realise my mistake I left the power connected to long and eventually friend my HDD (luckily it didn't damage anything else) Once I got right cable system worked fine.

[hitman]

Its semi-modular, but Im using all the correct power pins with it, and it is the only psu I have.

[MonnieRock]

Think I may have a problem with my psu...is there a way to test this without a psu tester?

 

 

Answer: Without a SunMoon PSU tester, you can not get complete test results.

 

But, you can detect some problems with a Digital Multimeter

 

Are you able to get the system booted with your PSU in place?

 

 

If so, without elaborate means of testing, you can run Prime95 on all cores, and use a Digital Multimeter on each rail. Test and record values idle, then test and record values under full load with prime. Kinda of a basic way but can show if there are some problems. You will not get false positives of your test. If it renders bad readings , they are bad. If it reads ok, well, then it "might be ok". Without a SunMoon tester, you can not really stress the unit under full load conditions. Understand? Remember, Higher than ATX specs is just as bad as Lower than ATX specs. 1%-2% varible is ok.

 

Secondly, do research on your motherboard and find the locations you can meter out the true voltages your board is putting out. Do not, I repeat, do not trust any values that are shown from PWM senors your board shows in your BIOS or in software running within your operating system.

 

I do not know your exact model # so I could not read on the design. One thing I suggest. Most 1000+ watt units have a primary and a secondary transformer. Make sure you are not using the PCI-E connectors for both cards on one side of the transformers. To add to that, If you are using the GTX 260's, they have 2 connectors on the card. Make sure each card ( both connectors) are running off the same transformer. So your primary card gets one rail, one side of the transformer with both connectors. Your other card gets the other transformer, another rail, and both connectors from same source.

 

For example:

 

V1 & V2 Primary side of transformer

 

V3 & V4 Secondary side of transformer

 

Primary card use PCI-e connectors from V1 & V2

Secondary card use PCI-e from V3 & V4

 

It is very easy to mix things up for example ( this is a no no )

6 pin PCI-e connector from V1 and 8 pin connector from V3 on same card

 

Somewhere in the manual that came with your PSU or a downloadable Manual should be information which rails are connected to the same source(transformer).

 

Also, make sure you are feeding your PSU good power from the wall. Crappy power going in, means crappy power going out. The coolermax series are known for not producing good power with sub-standard input voltages ( lower than 115 volts in North America)

A lot of companies show specs for their units using 230v input voltages to "Boost" numbers, but have lower efficiency when at 120v. The numbers game

 

 

 

If you are sure it is dead, Look for models that are using the Channel Well PUC design. Currently it is the most stable, true source of power. Some of which are the Thermaltake 1200 and the Corsair HX1000. Also, do not go with ( just a name) There is a comapny that used to be known for tight regulation, professional power but over the years their product is not what it used to be and they are living off their name, and charging top dollar as where some units using the Channel Well design are cheaper and deliver much better power.

 

Also, make sure the connectors to your Motherboard are not on the same rail as all your devices. Spread things out.

 

Are you using any high wattage fans? The Motherbaord connectors can only deliever so much power.

 

I see you are using water cooling. How many amps and watts does your water pump take. Do you have a fan plugged into the CPU fan PWM port, maybe your Motherbaord thinks you do not have a CPU cooler and will not start the system because you are using water cooling without being able to get booted to disable that safety feature.

 

Just kind of add all of these things into the equation. Do not load up a single rail just because the connectors are in convenient routing. Plan the spread of power.

 

Check your ram too. Maybe put 1 dimm in. Not populate all three slots.

 

 

Hope all of this helps. If you need more help, let me know.

 

Thank you,

Monnie

Edited December 25, 2008 by MonnieRock
Because I think faster than I type :)

[hitman]

Ok. First off, the motherboard has 30+ some LED diodes for troubleshooting in case of a failure or an overclock gone bad. Im not using the water pump at the moment because I need adapters for the socket 1366. My gpu's are both unhooked. I have the stock HSF, cpu, and the memory installed and thats it. Ive tried different wall sockets and all tests are typical. I dont have a multimeter floating around or a psu tester either. All my power cables are routed correctly since everything is basically color coded (and I have the manuals in front of me).

 

I get a few diodes to light up...the fan on the PSU spins for a half second, and the board, case fans, all diodes on the board, etc...all flicker on briefly. This is my ONLY outcome of all the tests Ive so far conducted.

 

I had the intention of upgrading my computer. I didnt realize I was going to have to buy a brand NEW computer instead.

[MonnieRock]

Ok,

 

I suggest, do a build on a workbench,kitchen table, where ever there is good lighting. (Seeing is believing.) Not inside the case. Place the MB on the anti static plastic that came with it or use a rubber mat to insulate. Only install one GPU, One Dimm( usually the one closest to the cpu socket), Connect bare essentials. One CD-rom, One HDD.make sure your CPU is in the socket correctly. Sometimes something so simple can be such a headache. Check, then double check everything. Connectors,Jumpers,wiring,cards seated properly,everything,if you are using conductive thermal paste, make sure none got in "bad" places. then take a break, smoke a cigarette if you smoke ( hehehe I smoke like a chimney), then check things again. With all those LED's there should be a code that refers to a certain failure. Even if your PSU is not "up to snuff", it should at least get you booted into the BIOS since it was working before with only 1 GPU,1 HDD,1 CD-Rom, 1 Dimm. There is most likely an overlooked issue. Be patient and thorough as it can be painstaking.

 

As for me, I always do a build outside the case first. Making sure all componets function. I have never had a dead Gigabyte board before. Also it eliminates the possibility of a grounding issue from the case if the MB is touching somewhere.

 

Might do a CMOS clear. Should be a jumper setting that clears it.

 

 

A very good investment is a good digital multimeter :thumbup:

Thank you,

Monnie

Edited December 25, 2008 by MonnieRock

[hitman]

I troubleshot this thing down as far as removing everything (including CPU, ram, HSF, HDD, etc...) and results are typical. Only thing I had on the motherboard were the POWER LED wires to turn it on.

 

I hate the hell out of the holidays.

[Kuky]

Hitman, have only following installed / connected:

 

Motherboard

CPU

1 stick of RAM

VGA

PSU

HDD

Keyboard / mouse (but you don't even need the mouse)

 

All other things leave out, no CD ROM, Floppy etc. If that doesn't boot even in motherboard BIOS and you're sure everything is connected properly you must have some faulty hardware. If it's PSU it won't do anything... not even short time of fan spinup, nothing. If you have another VGA try that, and of course other stick of RAM on its own... or another HDD. With faulty motherboard or CPU it's bit harder to tell which it is unless you have spare CPU with same socket which not many of us have.

[hitman]

Tried it all the way down to just the motherboard and psu again. The psu spools up like the past 3 times I explained it...fan rotates 3 times, if that, and powers down. Typical.

[hitman]

PSU was trashed. Dont know if Ill pull it apart later, but I think I may have popped a fuse somewhere inside, and I dont want to void warranty. If I do, can I up the amp rating by installing 36a fuses instead of the 30-30-20-20 amp fuses w/o screwing up anything?

 

Found out something interesting about it as well...seems like I have the 1350w power supply. Who knew.

Edited December 29, 2008 by hitman

[Kuky]

Never ever make any changes in the PSU Hitman or you will most likely end up setting it on fire which can light up rest of your PC/Huse ;) (unless you're electrical engineer and know the PSU circuitry inside out :D). Fuse is there for a reason... to much current through wires and componenets and they'll heat too much insulation will start melting/burning)

 

I believe rating of 1200W and you seing 1350W is because 1200W is RMS power rating and 1350 is absolute MAX peak power (and you don't wanna be running it at peak power to begin with for same reason as you shouldn't modify fuses etc)

Edited December 29, 2008 by Kuky

[hitman]

I believe rating of 1200W and you seing 1350W is because 1200W is RMS power rating and 1350 is absolute MAX peak power

No, the model number was different than the model I purchased...the one I purchased was a CUQ-1200B..the one I HAVE is a CUQ-1350B. I know the wire sizes and they can handle an extra 6 amps...but that is really pushing it.

[diveplane]

sounds like a dying psu or faulty circuit supply , swap it out with a new unit.

 

first i would check the voltages on each rail with a tester or meter.

Edited December 29, 2008 by diveplane

[hitman]

Yes I guess I didnt already do that, thanks.

[Kuky]

No, the model number was different than the model I purchased...the one I purchased was a CUQ-1200B..the one I HAVE is a CUQ-1350B. I know the wire sizes and they can handle an extra 6 amps...but that is really pushing it.

 

well that explains it then :smilewink:

[MonnieRock]

PSU was trashed. Dont know if Ill pull it apart later, but I think I may have popped a fuse somewhere inside, and I dont want to void warranty. If I do, can I up the amp rating by installing 36a fuses instead of the 30-30-20-20 amp fuses w/o screwing up anything?

 

Found out something interesting about it as well...seems like I have the 1350w power supply. Who knew.

 

Curious to know, how did you come to the conclusion the PSU was bad?

 

 

Thank you,

Monnie

[hitman]

Took it to a computer store and had it tested there. No power out to anything. I would be tempted to say they lied to me, but they dont have any power supplies my size and they know it. Anyways Im getting a TT 1200w psu today, so hopefully Ill be up and running today.

[MonnieRock]

Anyways Im getting a TT 1200w psu today, so hopefully Ill be up and running today.

 

Good choice. Based on the Channel Well PUC design. I am using one too. Flawless :thumbup:

 

Thank you,

Monnie

[hitman]

Wasnt able to get the TT1200w like I thought I would...I rma'd my psu, and guess what? They received it in working condition. The same computer store I tested this at also told me my motherboard, cpu, and ram posted when I had it tested there a few days after I had my psu tested. Makes me wonder what kind of BS they are telling me.