Quoted from Knxwledge:

Grounding out the transistor manually shows that your wiring to the solenoid is good, but does not mean the transistor itself is good. Start with changing the transistor, very likely that's your problem. You can diode check it against the other transistors if you want to be sure. Could also be the diode or resistors in circuit.
As for switch test, it's telling you what switch is closed, not the number of switches closed. Switch 2, according to the manual, is one of the coin chute switches, which is odd. Is the game adding credits seemingly at random?