Ad H

I fixed it with the same power chassis plug, isolated with a small piece of epoxy and 4 M2 bolds/nuts and minus on the center pin.

I think you are right. I am going to change this with an isolated power jack.

and it is working, no short circuit. I know that most pedal power supplies have the minus in the middle.

I modified the polarity of the power supply..

I used a non isolated power jack and 9 volts DC in the center pin. So the minus is connected to the chassis. The battery minus is...

Thank you all for the comments and especially the wiring diagram posted on this site; it was very helpful to me. As you can see, I used...