Hey, how goes it ?

For a first machine, you picked an awesome one ! "Blood is, such precious thing in this time"

I assume you have a digital multimeter, yes ?
You should totally test your parts before installing.

Honestly ? If i were you ? I'd make sure i have the manual in front of me and i would be testing every single thing for resistance and continuity and writing it all down. I would then take every single fuse in the game (yes all of them, even under the playfield) and literally throw them all out. Then with the help of the manual go and replace them all.

With the manual you can identify every part, then type it in a search engine and find out it's specs. Compare with your notes. Eventually you will have one or more items that are out of spec. Fix all those issues and see if that helps.

There might be a bad diode, or resistor or transistor or a break in the circuit path in the board, etc.

Or maybe you just simply need to re-solder something ?

Shotgunning parts into a machine usually never works. Knowing how to use a digital multimeter, logic prob and soldering are tools that will help you overcome this issue.

All these things can be learned from youtube, and this forum.

I will totally help you as much as i can, i take care of a Dracula machine at my work, so if need be we can compare machines and stuff !

Fuses are cheap and they go bad, causing resistance. A fuse can look good but be bad. When you get a used pin it should be the first thing you do.