Elektron Musical Instruments

yo folks, maybe somebody of you can help me,
i am currently in japan, tomorrow i will have a live gig on a party 
here, and i have a  problem with my MD now.
i bought a voltage converter in germany, which is supposed to convert 
the german 220 volt into japanese 110 volt.
when connecting the machinedrum to that converter, the md runs, but 
the display is almost unreadable, means very low on contrast. 
i also tried to connect my nord micro and my mpc to that thing, and 
had no problems..
i worry abit about my sweet MD, so i wanted to ask you if that 
behaviour is normal? i didnt have any problems in the past using 
voltage converters with the md..

cheers and sayonara,
steril-san