Hi. I have a western digital external hard drive, Its power supply broke. The power supply is rated at 12v 1.5a, i have a another power supply that is rated at 10v 1.5a. Can i use this safely.
The voltage is to low so it probably won't run the motor in the drive fast enough.A lot of power supplies actually put out more voltage than what they are rated and can be checked with a DC voltmeter.
If it appears to be working fine then it will probably be ok as long as it doesn't overheat and burn up.
get the proper voltage adapter with same or higher amperage as you will burn it out as it is in brownout mode which is not good for electronics.