All good advice Nino.. especially after what i found this morning on a Gtb Surfer i'm doing at the moment for a member here.

I hope you dont mind Nino but i've attached a couple of pics that will illustrate exactly the kind of thing you're talking about!

These pics are of what i found when i removed the bottom relay panel!! Yes that is the GROUND wire twisted around the power switch terminal Now the twisted red & black wires aren't connected to the switch in these pics but you can clearly see that they had been twisted onto the opposite (i assume) switch terminal!! I was quite horrified when i found this had been done.. especially as (and i'm a bit ashamed to admit this) i had had this game powered up testing the rest of the game  

This mess was hidden under the black power switch cover so i didnt find it until i had removed the relay panel, the  rest of the game was VERY tidy and with no other visible hack repairs, i had no reason to suspect anything was wrong... i could have very easily ended up VERY DEAD!!!!

The person who did this needs his ARSE KICKED until it bleeds  

EDIT; i wanted to point out that this game was bought and put into storage (never powered up)  by the owner before bringing it to me so it wasn't him who wired the switch this way