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Beginner PSU questions about 12V rails for GPU and how red PCI-E connector on PSU broke my DVD burner!

Tags:
  • GTX780
  • DVD Burner
  • Power Supplies
  • Nvidia
Last response: in Components
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September 20, 2014 10:06:31 AM

I think the red connector on COOLMAX CL-700B 700W PSU killed my DVD burner!

This is the first computer I've ever built. I bought the COOLMAX CL-700B 700W PSU (http://www.newegg.com/Product/Product.aspx?Item=N82E168...).

It's a modular PSU, and on the back of the PSU are two black 6-pin connectors and one red 6-pin connector:



I connected a cable that had a black 6-pin end to the red 6-pin connector on the PSU, and the other end of the cable to the SATA power port on my DVD burner. After I turned on my computer, I smelled some burning, and my DVD drive would not be detected by the BIOS, and I couldn't eject the DVD tray.

Can anyone tell me what the red 6-pin connecter on the PSU is for? I am trying to install a GTX 780 which requires both a 6-pin and an 8-pin connector. The PSU comes with a modular cable that is red on both ends, one end is 6-pin, and the other end is 6+2 pin:



I think I need this, but I'm not sure where to put it on my PSU - on the black connector or the red connector.

I also think that maybe my PSU cannot handle my GTX 780. It's an EVGA superclocked GTX 780 (http://www.amazon.com/EVGA-GeForce-GTX780-SuperClocked-...)

Here's a picture of my PSU details (my model is the CL-700B):



I think it means that there are 4 12V rails, and 3 of the 12V rails are maxed at 16A, and one 12V rail is maxed out at 12A. How do I know which color connector is for which 12V rail? Is the red connector under "PCI-Express Connector" the one with a max of 12A?

My 1st question: To what PSU connector (black or red) should I plug in my GTX 780 6-pin cable to?
My 2nd question: To what PSU connector (black or red) should I plug in my GTX 780 8-pin cable to?
My 3rd question: Can my PSU support my EVGA superclocked GTX 780?
My 4th question: How do I know which color connector on my PSU is for which 12V rail?
My 5th question: How come my PSU box shows 4 12V rails, but there are only 3 12V rail modular connectors?

More about : beginner psu questions 12v rails gpu red pci connector psu broke dvd burner

a b ) Power supply
September 20, 2014 10:16:30 AM

I cannot find any picture that matches your description. Sounds like your specific model uses the same plug for the SATA cables and PCIE power cables... and you plugged an SATA cable in the 12V-only PCIE connector. Yup, that would certainly hurt whatever you end up powering with that cable.
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a b ) Power supply
September 20, 2014 10:23:19 AM

The red is a PCIe connector that goes to a video card!

You killed the drive by attaching the peripheral power cable to the PCIe slot.
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September 20, 2014 10:24:18 AM

InvalidError said:
I cannot find any picture that matches your description. Sounds like your specific model uses the same plug for the SATA cables and PCIE power cables... and you plugged an SATA cable in the 12V-only PCIE connector. Yup, that would certainly hurt whatever you end up powering with that cable.


Thanks. I just updated the post with the pictures I meant to put in from the beginning.

What I don't understand is why, if all the voltage is the same across all 12V rails (black and red connectors), why it would damage my DVD burner?
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a c 2405 ) Power supply
a c 75 Î Nvidia
September 20, 2014 10:27:18 AM

Very very poor power supply , replace it right away.

Tier 5 - Other than the units listed above for any of these brands, NOT RECOMMENDED. Replace ASAP if you have one.

A-TOP Technology
Apevia
APEX (SUPERCASE/ALLIED)
Aspire(Turbo Case)
ATADC
Athena Power
ATRIX
Broadway Com Corp
Coolmax :bounce: 
Deer
Diablotek
Dynapower USA
Dynex
EagleTech
FOXCONN
FSP Everest
HEC Orion
Hiper Type-R
Huntkey
I-Star Computer Co. Ltd
In Win
JPAC COMPUTER
Just PC
Kingwin Inc.
Linkworld Electronics
Logisys Computer
MGE
MSI
NMEDIAPC
Norwood Micro/ CompUSA
NorthQ
NZXT
Okia
Powmax
Q-Tec
Raidmax
Rocketfish
Rosewill
SFC
Shuttle
Skyhawk
Spire Coolers
Star Micro
STARTECH
Thermaltake Purepower NP
Thermaltake Purepower RU
Thermaltake TR2 (and TR2-RX)
TOPOWER TOP
Ultra X-Connect
Ultra X2 >greater than 700 watt
Ultra LSP
Wintech
XION
YoungYear
Zebronics
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a b ) Power supply
September 20, 2014 10:27:54 AM

Your burner uses 5V and the PCIe connector supplies 12V to those pins.

edit: and yes, as SR-71 says, use a high quality PSU if you value your expensive video card. Better PSUs should not let you make that incorrect connection, at least all of the ones that I've used are keyed differently on the PSU end to prevent incorrect attachment.
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September 20, 2014 10:40:35 AM

RealBeast said:
Your burner uses 5V and the PCIe connector supplies 12V to those pins.

edit: and yes, as SR-71 says, use a high quality PSU if you value your expensive video card. Better PSUs should not let you make that incorrect connection, at least all of the ones that I've used are keyed differently on the PSU end to prevent incorrect attachment.


Ok. If I'm understanding you clearly, you're saying that the black SATA "12V" rails actually supply 5 volts only?

If that is the case, how do I connect my GTX 780 to it? It requires both 6-pin and an 8-pin connectors? I'm assuming that the 6-pin and the 8-pin both need to be fed from PCI-E connectors on the PSU (both need to be 12V, not 5V)?
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a b ) Power supply
September 20, 2014 10:44:28 AM

No, I'm saying that the pins on the connector that should have carried 5V if properly attached were instead carrying 12V due to the improper attachment.

You have one 6 or 8 pin connector. You will need an adapter to use a couple of Molex (the old 4 large pin) adapters to a PCIe 6 or 8 pin, whichever you need after using the one on the PSU. That or get a PSU that has two PCIe connectors.
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September 20, 2014 10:56:09 AM

Err looking at the spec I do not think it is up to powering a 780. The 780 recommends 42A on a single 12v rail, you have 18 max on a single rail? Wait for others to comment but I do think you need another PSU
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a c 2405 ) Power supply
a c 75 Î Nvidia
September 20, 2014 10:57:26 AM

The power supply is very very poor quality , I wouldn't run a 780 with it.
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September 20, 2014 11:11:00 AM

SR-71 Blackbird said:
The power supply is very very poor quality , I wouldn't run a 780 with it.


Ok, looks like I need a new PSU. What makes this one "very very poor quality"? Just the brand? Or the number of amps per rail, or both?

How do I know which 12V rail is on which PSU connector, or does it not work like that?
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a b ) Power supply
September 20, 2014 12:09:17 PM

The PSU manufacturer was dumb and used the same connectors for 12V-only and mixed-voltage cables thinking color-coding would be enough to prevent mistakes... this is negligent design and likely worthy of a class-action if there are more people out there who killed devices because of it.
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a b ) Power supply
September 20, 2014 1:14:40 PM

jeff0000 said:
SR-71 Blackbird said:
The power supply is very very poor quality , I wouldn't run a 780 with it.


Ok, looks like I need a new PSU. What makes this one "very very poor quality"? Just the brand? Or the number of amps per rail, or both?

How do I know which 12V rail is on which PSU connector, or does it not work like that?
Quality of the components and what the unit actually delivers at operating temperatures under load is what makes a PSU good or bad. Read some review of good units (like many of the Seasonic) and you will see that they deliver consistent current that meets or exceeds the specs. Some brands have a strong reputation due to producing mostly or all good quality products, others do not and they are on the list SR-71 posted as tier 5. It would be like Mercedes and BMW as tier 1 and Yugo as tier 5, just a completely different quality level of the distinct models.

A lower power PSU is not necessarily a bad unit, as it may be very high quality and useful for people that don't have high power requirements, for example in a HTPC using on chip graphics. Some units have multiple 12V rails and some have just one, but that doesn't really matter as long as the total amps of the 12V rails is more than sufficient for your needs.

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