Hi there. I´ve got similar problems on my DMM. It works somehow on short delays, but it seems there is no way to turn off chorus/vibration effect. Been using it few times and then it was stored about two years and after that when it start to use it again the problem exists. Some technicall guy had a look in it and said it´s minor problem and comfirmed he had solved the problem, but nothing was really done..
BTW.. it came whit AC220/DC18v500mA. I read it takes DC 24/100