All,
the cradle has a voltage regulator inside it which is used to adapt from the mains transformer down to the 5 volts needed for the USB interface and the hard disk drive. When I bought my unit from the US it came with a supply that could be set to a range of voltages, so the first thing that I did was to open up the cradle and see what was inside.
For the electronics people (like me
) the USB2 version of the cradle uses a 34063 type switch mode power supply controller. This is good for a wide range of input voltages, and the upper
absolute maximum limit of the circuit is set by other components to around 25 volts.
My unit is very happy running from either 9 or 12 volts from a regulated supply. (I binned the supply from the US since it was not regulated and had US style pins for the mains socket).
While a 7.5 volt supply seems a bit low, it is probably giving out more that that unless it is a regulated unit (most cheap units are not). The drive in the DMS takes at most about 500mA at 5 volts, and the USB to ATA adapter chip and it's local flash memory chip take very little from two smaller regulators (probably 3.3 volts).
So any supply giving around 9 volts or so to the cradle and capable of 800mA should be more than capable. From my investigations above, 12 volts seems fine. A supply of up to 15 volts non-regulated should be OK, but I would avoid going higher just in case something goes bang.
Hope ths helps,
Les.
