All inputs, outputs, switches, and potentiometers have been tested.

Repaired left channel audio output issue (removed and reinstalled speaker relay; improved contacts; applied protective treatment).

Repaired BALANCE potentiometer rattling (cleaned all potentiometer and switch contacts using contact cleaner and e-cleaner).

Cleaned input and output connectors (removed grease and oil residue; polished).

DC/BIAS checked and adjusted (DC/0V, BIAS/15mV).

One missing insulator repaired (replaced entirely with AU-D907 parts).

Internal, exterior, and knob cleaning.

This is an early model AU607. While it showed signs of age, such as rattling

and faulty contacts, as well as grease splatters from the kitchen, it has been restored to good working condition through maintenance.

There is a thin scratch about 1 cm long on the left corner of the front panel.

The top cover has faint scuff marks and slight rust spots.