Yioryos - I just assume your ML27.5 has linear power supply. If it has SMPS it will not do anything (start) to about 70VAC then it will put full operating voltage on the caps.
You can buy variacs... just about anywhere (that sells electronic items, that is). In its simplest form, it's a wall-wart with a multiposition switch on it indicating different output voltages per position... You just need the appropriate variac (i.e. TALK to a sales tech) Make sure you don't reach HIGHER voltage than the caps indicate (70? 80? V).
HOWEVER, I strongly suggest you get a TECHNICIAN to do this.
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