[SOLVED] Can a 3.5" SATA hard drive be powered by a 12 volt AC adapter?

tom2u

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Or does it need both 12 volt and 5 volt power? In that case could I use a 12 vdc AC adapter and a 5 vdc AC adapter wired up to a molex plug with a SATA plug attached? (Yellow for 12v and red for 5v.) If so, how much current would I need out of the AC adapters?
 

tom2u

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That is great news.
A few questions.....

What amperage would I need to supply off that 12 vdc AC adapter?

I read somewhere that said it uses 12 volts for the motor and 5 volts for the electronics. But maybe it extracts the 5 volts from the 12 volts input.

But why would molex plugs offer both 5 and 12 volts and why 2 grounds?

And why do SATA plugs have 15 conductors?

Is it better to use the SATA plug rather than the molex with a molex/SATA adapter to power the hard drive?
 

tom2u

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Those 3.5" external USB enclosures that are powered via a 12VDC barrel connector derive 5V from the 12V supply via an internal switchmode stepdown converter.

Here is an example from a WD My Book:

Western Digital My Book Essential bridge PCB, 4061-705094:
https://hddoracle.com/viewtopic.php?f=112&t=1032

Ha! As I thought. Thank you. Now I wonder if I can power a SATA drive with 2 AC adapters. 12 volts is for the motor so that would undoubtedly have to be higher amperage whereas the 5 volt one for the electronics probably needs almost nothing. Hey, we all have tiny SATA drives lying around from the past to mess with. This is my high achievement life.....lol. Playing with SATA drives.
 
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