I connected a 1TB 3.5" HDD with a breakout cable to my notebook. When I start the notebook, the HDD is not spinning up nor is it getting recognized. I toggled the Bios options AHCI on/off and LBA to Dos/other, with no success. Could it be that the sata power connector on notebooks only delivers enough power for 2.5" HDDs?
Technically everything is working fine. Usually I use the notebook with an SSD. A 2.5" HDD connected to the breakout cable works. The 3.5" HDD connected to my desktop PC works. I'm getting a couple of old HDD ready to sell through ebay. Having a 2nd PC to test and delete would be very useful to me.
Best Answer
Most 2.5" HDDs only need the 5V power rail from the SATA power cable to fully function. If you look at any portable HDD that's only powered by USB you'll see there's no additional power cable and they're only ever 2.5" disks; because USB only provides 5V. Yes, some disks come with a USB "Y" cable for additional power but this is for additional current, not voltage.
3.5" HDDs require both 12V and 5V power rails. Again, the desktop 3.5" HDDs usually come with (or require) an external power source because the USB connection itself cannot provide enough power.
I will guess that your notebook SATA does not have the 12V power because it does not ever need to power a 3.5" HDD.