PLAN B analog blog

I just received a Model 15 VCO I bought 2nd hand, shipped from Italy
to UK. When plugged in (and double checked its all correct) to the
power supply in my Analogue SOLUTIONS case I get nothing but a buzzing
from the power supply. If I take it out all is fine again. I've had
this before with loose power connections so I guess its some sort of
grounding issue? I checked the module over and cant see any loose
chips or wires. 

Any suggestions?
Thx