Yamaha MODX6 Service Manual page 50

MODX6/MODX7
4. Other Inspections (Check in Usual mode)
Test Item
Popping noise
Noise Level
50
Checks whether the popping noise is output properly or not when the power is turning on and off.
1) Connect the Oscilloscope to the output jacks.
(Connect the plugs to both L and R output jacks at the same time.)
2) Set the [MASTER VOLUME] to the maximum position.
3) Press the power switch to check the noise level indicated on the Oscilloscope when the power is
turning on and off.
No problem if the following conditions are satisfied.
[PHONES] (33 -ohms
load)
PHONES L: 500 mVp-p or less
-ohms
[OUTPUT] (10k
L/MONO : 400 mVp-p or less
Checks whether the noise is output from the OUTPUT jack and PHONES jack properly or not.
1) Connect the level meter to the output jacks.
(Connect the plugs to both L and R output jacks at the same time.)
2) Set the [MASTER VOLUME] to the maximum position.
3) Measure the output level and confirm that the measured values are within the specified range.
[PHONES] (33 -ohms
load)
PHONES L: -80.0 dBu or less
-ohms
[OUTPUT] (10k
L/MONO : -80.0 dBu or less
Instructions
PHONES R: 500 mVp-p or less
load)
R : 400 mVp-p or less
PHONES R: -80.0 dBu or less
load)
R : -80.0 dBu or less