Yamaha EMX3000, Service Manual

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EMX3000
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8. DISTORTION FACTOR
• In the state as described in 1, check that the distortion factor when +14dBs output is obtained at each output terminal is 0.1%
or less (except for REC OUT and INSERT OUT).
• In the case of C-R/PHONES OUT, set the 12 o’clock point of the level control to the Norminal position and the master fader
control to 5 on the scale. In this state, check that the distortion factor when +3dBs output is obtained is 0.2% or less.
• When taking measurements in [Table 2-1] and [Table 2-2], set the GAIN trim of the channel being measured only to the
maximum position but the GAIN trim of other channels to the minimum position.
• When taking measurements in [Table 2-3] and [Table 2-4], set the GAIN trim of the channels to the minimum position.
9. MAXIMUM OUTPUT
• In the state as described in 8 above, check that +20dBs output with 1% or less distortion factor is obtained at ST1 OUT (L, R),
ST2 OUT (L, R), MONO OUT, MONI 1 OUT, MONI 2 OUT and EFFECT OUT. Also, check that +8dBs output with 1% or less
distortion factor is obtained at C-R/PHONES (L, R) OUT.
10. EIN
• In the state as described in 1, set only the fader and GAIN trim of the input channel to be measured to the maximum position
and the fader of all the other input channels to the minimum position and short MIC IN with 150 ohm. Then check the noise
level obtained at ST1 OUT (L). It should be -65.5dBs or less. If it exceeds -65.5dBs, calculate the input converted noise level
and check that the result is 126.5dBs or less. (Use the DIN audio filter.)
11. RESIDUAL NOISE
• In the state as described in 1., set all Fader/Level controls in the input section to the minimum position. Then set the Fader/
Level controls in the MASTER section in [Table 11-1]to the maximum or minimum position and check that the noise level is at
the level indicated in [Table 11-1] or less.
Fader or Level control ST1,2 OUT (L,R) MONO OUT MONI 1,2 OUT EFFECT OUT C-R/PHONES OUT
Maximum -87 -87 -87 -83 -78
Minimum -95.5 -95 -95 -95 -97
[Table 11-1] Residual noise [Unit: dBs]
12. PHANTOM POWER SUPPLY (+48V)
• Connect a 10k ohms load resistance between pins 1 and 2 of MIC IN to short-circuit between signals 2 and 3. Then check that
+35 +/- 3 V voltage is obtained at both ends of the load resistance when the PHANTOM switch is turned on.
13. DIGITAL EFFECT
• In the state as described in 1, input -16 dBs/1kHz signal to MIC IN of channel 1, set MONI 1, 2 level controls of channel 1 to
the minimum position and check that -30dBs or more signal is obtained at MONI 1, 2 OUT when the DIGITAL EFFECT switch
is turned on. Also, check that a signal in the same range is obtained when the PARAMETER control is set to the minimum
position. Change the PROGRAM select switch to 2 to 16 and perform the same check.
• Check that the EFFECT function works when the signal from the music source is input.
• Check that the DIGITAL EFFECT function can be turned on and off using the foot switch.
• In the state as described in 1, change all the channel fader settings to the minimum position. Then turn on the DSP switch and
check that the noise level at ST1 OUT (L, R) is -61dBs or less. (Use the DIN audio filter.)
14. STABILITY
• Connect 10pF to 0.1
µ
F capacitance in parallel with the load resistance at each output terminal and check that no abnormality
such as oscillation occurs.
• Set all the VR and EQ controls to the maximum position and check that no abnormality such as oscillation occurs. Be sure to
connect a load resistance to the power amplifier for this check.