Yes a power supply affects USB power. It *may* be the cause.

If the drive is turning itself off intermittently:
One thing to check is the drive's 'auto ability' to sense power.
It may be shutting off during use because it senses it isn't getting enough power.
It could be a power supply issue -
Some PGMusic hard drives come with a USB cable that has one drive side connection and two computer USB connections.
This boosts the power to the external drive.

Did you get one of these with your hard drive?
If not this may not be applicable, but if you did -
Have you tried connecting both USB connections on the supply side?
One connection handles power and data like a normal USB cable, the second connection supplies only power, from what I understand.

As mentioned, sometimes system settings actually tell a USB port to shut down after X amount of time too.
Intermittent (unexpected) shut downs aren't often mentioned here, so I suspect something other than the drive itself as the root cause. Course I been wrong many times before.

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