Undervolting a switch

I got a switch discount price down at the local computer shop... discount because it had no power supply! So I ordered a power supply, but oops, its got the wrong connector.

The input power spec is 7.5V 1.0A DC.

Right now, I'm powering it with a 5V 1.0A DC adaptor for my Zip drive which nobody ever uses. Its an 8 port switch and I've only got 2 computers plugged into it right now, it SEEMS to be working just fine.

Is there any risk to the hardware undervolting like this? It shouldn't be too much of a problem really, Its just a matter of time till I get the right plug for the power supply I ordered.