Power adapter for Centre 304

[jeffdt]

I noticed a jack for a power adapter on the side of the centre 304. I see no reason to continue using batteries since I never move it, and I had a minor freakout the other day when the battery died mid-roast.

After a bit of research I believe what I need is a 9V DC negative centered adapter, but I don't know what size. I tried the 9V adapter from a guitar amp but it was too big. Has anyone bought an adapter for their centre and can point me towards one I can buy online that would fit, or offer tips on figuring it out myself?

Thanks!

[SusanJoM]

Jeff, there is a manual for the Center 304 in the Resources section.
I saw some specs for the AC adapter, but I'm not sure if they are the ones you need. 
Look in Resources > Phidget etc (the Center is an 'etc).