So some stuff happened, it is 168.3 V AC but when i tried to measure terminals 20 and 21 i got 170 V and then it started to go down slowly, then i remeasured the AC Voltage between 18 and 19 and got 0 V, I checked the fuse and it was blown, replaced it, tried to measure 20 and 21 again and blew another fuse, replaced it again and then every measurement was regular and sound is back again.
Should i check something to make sure I don't blow another fuse or just so I don't get those irregular measurements?