Few questions on my new Thunderbirds machine

[Kaasie]

Hello ,

I just purchased a Thunderbirds Classic Pachislo. I've read the FAQ and other posts but see different answers;

Is it possible to play with only 1 credit or always 3?

When my machine is in bonusmode and I want to reset it, it does not work when I push the doorkey to the left. I;ve checked the cables and everything seems to work. Can it be that this black connector where the metal goes trough is defect? Or is it unpossible to reset while being in bonusgames?

Thank you!!!