Checked the nanual for the test presses and will try that a bit later. So once I know the transistor number what will that indicate? Do I need a new one or do something else.

Also wondering why the drop targets just keep resetting and the ball doesn't go into play. Oddly enough i push all the drop targets and they go down but when they reset only 2 stay up...

Is the apron the cover of the solenoid?

Tks for the help with this - I have a bit of electrical/mechanical knowledge but am very new to pinball machine maintenance. Really keen to learn the workings of the new machine though... :-)

The manual tells you what transistor fires each solenoid.\

I am not familiar with Cosmic Princess but it may be a part of the game that you start off with certain targets up and others down, once you hit the ones that are up then it gives you others to hit.

The apron is the steel cover at the bottom of the playfield, the ball launch solenoid and mech is under there.
Take the apron off, check the resistance of the solenoid with your multimeter, if it is under 3 ohms resistance its probably cooked, also check the driver transistor on the solenoid driver board on diode mode with your multimeter, the link I posted will tell you how to do that, compare it against others that you know are working ok.
A visual inspection of the transistor may reveal damage too.