Harley Benton HBAC-20 

Start problems with HBAC-20? Here is how to repair it:

Amplifier have idle chip and it start (red led) when you play quitar and go back to idle (green led) when 30min of no use.

I couldn't fix it so i add red wire to start amplifier powersupply when power switch is on.

I added red wire shown at picture to connect negative pole to relay coil.

Now amplifier starts and shut down only at the power switch.