For 3,5" HDD you need an usb-case with extra power. The standard usb power is not enough for this needed power.
Most usp ports deliver about 50-70mA at 5V, so you must use a case with an external power supply. This is also needed for eSATA ports. Hans > > The smallest 3.5" HDD (3 TB) for which I found official Seagate > documentation said that it used 8 watts while operating. > > https://storedbits.com says a 7200 RPM hard drive would normally consume > 20-25W for 5-10 seconds during startup. It will then idle at around > 6-8 watts. The average power consumption during read/write tasks > will be around 8-12 watts, and the maximum can go up to 16 watts. > > I would be surprised if the transformer for the enclosure > did not deliver sufficient power for the type of > drive that the enclosure is intended to enclose. > > I have tried multiple USB jacks on the computer, of course.
