Yamaha imx644 Service Manual page 37

5. Factory setting
(1) Turn off all of the [PAD] switches.
(2) Turn off all of the [+48V] switches.
(3) While pressing the MEMORY buttons [A] and [D], turn on the power switch and keep pressing those two buttons.
When all matrix indicators of MONO1, MONO3, MONO5, STEREO 1 and STEREO 3 light, release those two buttons.
(4) Once turn off the power switch.
(5) Turn on the power switch again without pressing any buttons.
Confirm that all MATRIX indicators light and there are no big difference in their brightness.
(6) Input the 1 kHz, -21.8 dBu sine wave to STEREO INPUT 1, measure the output voltage at OUTPUT 1 and confirm that the measured
voltage is +4 dBu ±2 dB.
(7) Turn off the power switch.
(8) Set all the volume controls to the minimum position.
IMX644
37