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Power supply question - SATA MOLEX's

Last response: in Components
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October 3, 2009 4:10:34 PM

Hey all!
Im no newbie when it comes to computers, but im lacking ONE SATA molex connector for a hard drive, right now im running a 4pin molex converter. Would it be a *bad* idea to cut the wires to the standard 4 pin molex, and run another SATA one? (of course i would have to tap into the connector for the last wire, on the previous SATA molex though)

Just curious what you guys think. Btw, its a 420W ENERMAX P/S, so its not a cheap one.

-Dan
a c 144 ) Power supply
October 3, 2009 4:19:37 PM

Why not just run an adapter to another molex? Or use one of those single molex to two molex adapters ( Y-adapter) and use two molex-SATA adapters?
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October 3, 2009 4:21:22 PM

I was going to, but i have the spare molex here, and i dont mind actually soldering and heatshrinking it. ANd it will look alot cleaner IMO. My case as it is, is full of cables...
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a c 144 ) Power supply
October 3, 2009 4:30:58 PM

To be honest, that's what I would do. But then, I have more than 40 years of experience maintaining all sorts of military electronics, so my soldering skills are more than adequate. :) 
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October 3, 2009 4:38:55 PM

Molex is a very simple standard:

BEST WAY is to remember that the 2 black wires
connect to the 2 middle pins: both are GROUND.

That leaves just 2 more wires -- one Yellow and one Red:

http://en.wikipedia.org/wiki/Molex (see diagrams and photos)

Yellow is +12 Volts

Red is +5 Volts (also known as 5V "Stand-By" voltage or "SB")

The Red and Yellow wires must
connect to the correct pins
inside the Molex housing.

Note well the 45 degree corners
along one long edge of the connector,
and the 90 degree corners
along the other long edge, like this:

http://en.wikipedia.org/wiki/File:Molex_female_connecto...


MRFS

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October 3, 2009 4:39:13 PM

Good enough for me. Now i guess i should ask though, will i experience a voltage drain on that line cause of the extra molex? Already, i think my PS may be too small for the stuff im running. I'll shoot a list off so at least you can give a comment on it:

Pheneom 2 X550 (NOT OVERCLOCKED)
Asus M4A78 PLUS
ATI Radeon 4670 (saphire, motherboard run)
4 GB's of DDR800 ram (generic)
2x 500Gb hard drives
1x 1TB hard drive (all SATA)
1X DVD SATA drive
1X DVD IDE drive (for on the fly copying)
Onboard sound (Digital optical out)

All this is running on a 420W Enermax P/S. I have a feeling i may be running short on power.
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October 3, 2009 4:41:08 PM

> right now im running a 4pin molex converter


p.s. Confucius say: "If it ain't broke, don't "fix" it!" :) 


MRFS
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October 3, 2009 4:41:49 PM

MRFS said:
Molex is a very simple standard:

BEST WAY is to remember that the 2 black wires
connect to the 2 middle pins: both are GROUND.

That leaves just 2 more wires -- one Yellow and one Red:

http://en.wikipedia.org/wiki/Molex (see diagrams and photos)

Yellow is +12 Volts

Red is +5 Volts (also known as 5V "Stand-By" voltage or "SB")

The Red and Yellow wires must
connect to the correct pins
inside the Molex housing.

Note well the 45 degree corners
along one long edge of the connector,
and the 90 degree corners
along the other long edge, like this:

http://en.wikipedia.org/wiki/File:Molex_female_connecto...


MRFS

The problem with this, is that the part i need is for a SATA drive. Im just going to cut and splice into my SATA power connector, and run the new wire there. I'll post a pic when im done, about what exactly im doing (Although, i think JSC knows what im doing)
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October 3, 2009 4:45:50 PM

> Already, i think my PS may be too small for the stuff im running.

Can you buy a cheap Watt meter e.g. from a local hardware store?

Don't forget to power your monitor and other peripherals
via a separate circuit, so you can isolate the Wattage
demand by that PSU.

Without having any specific details about the power
requirements of each of your components, I am going
to venture a guess that they are pulling about 300 Watts
MAXIMUM i.e. well within the Wattage rating of that PSU.


MRFS

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October 3, 2009 4:52:23 PM

> will i experience a voltage drain on that line cause of the extra molex?

To answer that question with confidence,
you would need to know the AMP rating
of the PSU's rail that powers that cable.

There is a major difference between PSUs
with only one rail, and PSUs that use
multiple rails: the rated Wattage will
NOT reflect the maximum current rating
of any given rail in a multi-rail PSU.

There should be a UL plate somewhere
on your PSU, with details about maximum
AMPs for each rail.


WHEN IN DOUBT, try to "spread" the load
across all available peripheral power cables
e.g. either 4-pin Molex or SATA input DC.

Assume about 10-12 Watts PER HDD,
maybe 15 during spin-up.

The other power cables are easily identified,
and they do NOT connect to disks and optical drives
e.g. 4- or 8-pin motherboard power, and
PCI-E video card(s) supplemental power.


MRFS
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October 3, 2009 5:56:40 PM

MRFS said:
> will i experience a voltage drain on that line cause of the extra molex?

To answer that question with confidence,
you would need to know the AMP rating
of the PSU's rail that powers that cable.

There is a major difference between PSUs
with only one rail, and PSUs that use
multiple rails: the rated Wattage will
NOT reflect the maximum current rating
of any given rail in a multi-rail PSU.

There should be a UL plate somewhere
on your PSU, with details about maximum
AMPs for each rail.


WHEN IN DOUBT, try to "spread" the load
across all available peripheral power cables
e.g. either 4-pin Molex or SATA input DC.

Assume about 10-12 Watts PER HDD,
maybe 15 during spin-up.

The other power cables are easily identified,
and they do NOT connect to disks and optical drives
e.g. 4- or 8-pin motherboard power, and
PCI-E video card(s) supplemental power.


MRFS


Wow man, your just full of information. It looks like, according to my PSU info, i should have enough power for all 3 drives on one line. What im going to do, is remove one regular MOLEX, and put a SATA one on there. Heatshrink and solder as well of course.

Thanks for the help man. Muchly appreciated. I'll take some shots of my PC after its done. I gotta clean up a couple wires first :bounce: 
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