Also have Magnum 240
I also have a Magnum 240 Compass detector. I have sent away for the manual, but in the mean time there is something that bothers me about it's behavior.
In all metal mode, after you ground tune it. You get the threshold volume the same when the coil is on the ground, or held in the air.
Switching to discriminate mode, if the coil is in the air and placed on the ground, the needle moves to -50 trash and stays there, and there is no threshold volume. HOWEVER... if you place the coil on the ground, switch to discriminate and even lift the coil a 'smidge' the needle jumps to +50-100 treasure. Even running it along the ground, if the level creates a hollow under the coil it goes off. Is this normal? Are you suppose to run in discriminate all the time? Do you only switch to it when you find a target in all metal mode? THen see if it does not register?
Just confused. (which is why I sent away for the manual).