tested external eqt with an alternative pioneer using same plug so all wiring is fine.

Because the thing reads in japanese navigating the settings is a pain.

It's an avic hrz-900 (raku navi, the one that speaks in a female japanese voice when you start the car)

essentially all functions work, but no sound comes out the inbuilt amp. I know some headunits have an option to turn off the int amp, but I cant find jack shit on this one on the net.. theres no mute setting.

If I open it up where should I be looking for burnt components?