Yamaha MG16/6FX Service Manual page 34

MG16/6FX
2-12. PEAK LED light-up level
Each LED shall light-up within the range specified in the table 2.12.1 when a signal is fed to the MIC input.
Table 2.12.1 [dBu]
INPUT PEAK LED
MIC -43 +/-2
2-13. Meter LED lighting check
PEAK LED lights up, when ST output level reaches +17.5 +/-2dBu.
0 LED lights up, when ST output level reaches +4 +/-2dBu.
Operate the fader and check that LED light up in order from "-20" to "PEAK".
2-14. Distortion Factor
In the signal routes of the Table 2.6.1 to 2.6.6 indicated with q to o, set the VR and Fader of INPUT and and MASTER to the
Nominal Position, and set the GAIN to the position specified in the Table (except PHONES).
Then, feeding each 20Hz, 1kHz and 20kHz signal, the distortion shall be less than 0.1 % when the output signal level is
+14dBu.
At the C-R OUT (L/ R), setting the Level Control to the 12 o'clock position, feeding each 20Hz, 1kHz and 20kHz signal, the
distortion shall be less than 0.2 % when the output signal level is +3dBu.
In the route q, check every OUT when the signal is fed to CH1, and check only the ST L OUT when the signal is fed to CH2
and other channels.
In the route w, turning the PAN/BAL control to L fully, the distortion shall be less 0.1%, when the ST L OUT signal level is
+4dBu.
In the route y, check only the ST L OUT and the ST R OUT.
2-15. Maximum Output
In the state 2-2, the distortion factor shall be less than 1% when the output level is +24dBu at ST L OUT and ST R OUT, and
+20dBu at GROUP1-4, AUX1 OUT, AUX2 OUT ,EFFECT OUT and C-R OUT.
The distortion factor shall be less than 1% when the output level is +7.5dBu at PHONES (L/ R).
In measuring the ST L OUT, the ST R OUT and the GROUP1-4 OUT, set the PAN or BAL Control to L or R fully respectively.
2-16. Equivalent Input Noise
In the state 2-2, connect between the CH INPUT MIC terminals (2 pin-Hot and 3 pin-Cold) with 150 ohms, the noise level
obtained at ST L OUT shall be less than -43.5dBu.
If it is over than -43.5dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less than -127.5dBu.
Connect between the ST INPUT MIC terminal (2 pin-Hot and 3 pin-Cold) with 150 ohms, the noise level obtained at ST L OUT
shall be less than -39.5dBu.
If it is over than -39.5dBu, calculate the input converted noise level (= noise level - channel gain) and it shall be less than -123.5dBu.
(Noise is measured with a 12.7kHz -6dB/octave low pass filter.)
2-17. Residual Noise
In the state 2-2, set the Fader and Level Control of all input CH to MIN and set the all Assign switch to OFF.
Then, the noise level shall be less than the level specified in the Table 2.17.1.
In measuring the C-R OUT and the PHONES, set the ST Fader to MIN.
Table 2.17.1 [dBu]
Fader/VR ST OUT
MAX -78.0
MIN -100.0
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GROUP OUT AUX OUT
-80.0 -75.0
-100.0 -100.0
EFFECT OUT C-R OUT
-75.0 -72.0
-100.0 -87.0