ENGL Gigmaster 15 (E315) attenuator circuit connection

When you're removing the chassis of Gigmaster, you may need to disconnect
three wires from the build-in attenuator on back grill.


Make sure that you've memorized the sequence of connections
- Blue/Black/Brown (left to right) before removing them from the PCB.

Pictures from Martin Zimmermann, ENGL service. Thank you, Martin.