Hi,
I had the same problem, bought a strategy 500 from the US, but used a step down transformer for ages. Works fine, but the bloody thing on it's own already weighs a million kilo's. After moving to Australia, I decided to get into modding the amp. no schematics available on the net, so you're pretty much stuck. Found out that it's more than simple, just 2 bridges you have to take out, put 1 in a different position and you're done.I'll try to make some pictures of the part you have to look at. I'll also test the voltages on all the wires and post em for you. my amp runs on slightly higher voltages now, because of 240/250 Volt, so you should be sweet with 230V. Sorry in advance if I'm taking a while getting this sorted, busy life unfortunately.
Anyway, great buy, I love this amp, great tone overall.
Mark