Hello from Slovenia

Welcome guy.

First thing to do if you are decided to make or repair any kind of electric device: build a current limited power supply. Although it may look complex, it's rather simple: build an outlet wired in series with a lamp socket. Place in it a filament bulb of rougly similar power as the device to be tested. Discard any other kind of bulb: led, gas discharge, fluorescent. This will be your most important tool. If the rig under test fail before or during repairing, the lamp will protect it, you and your money. Lamps has positive temperature coefficient: its resistance increases quickly with temperature and thus with current.

I know filament lamps are nowadays difficult to own, but believe me that the effort to get them is well rewarded.