Phantom Dc Voltage Test; Level Difference Between Chs; Voltage Gain Test For Ha-Gain - Yamaha DME24N Service Manual

DME24N/DME64N
e Total Harmonic Distortion
Input Frequency Input Level
1kHz -50dBu
1kHz -42dBu
20Hz -50dBu
40kHz -50dBu
r Noise Level
Measuring Method···Terminate the CHn input with
150Ω. Measure noise levels output from the CHn output.
(n =1~8)
Permissible range
-63dBu or below
If the noise level is not within the above tolerance, check
EIN (Eqivalent Inpit Noise) that EIN = Noise Level
Measured Value – (Voltage Gain at 1kHz) ≦ -127.
t Level Difference between CHs
The range of voltage gain difference measured in the
above step q will be defined as follows.
Permissible range
Within 2dB

2-1-2-4 Voltage Gain Test for HA-GAIN

Press "ENTER" to return "TEST CASE No. Selection
Mode" for a time.
Select the "TEST CASE:#3" (see 2-1-2-1 Diag Mode
Settings), and press "ENTER".
Input Frequency Input Level Specified Output Level Permissible range
1kHz -17dBu
In the similar procedure to the above, select the "TEST
CASE:#4" and press "ENTER".
Input Frequency Input Level Specified Output Level Permissible range
1kHz -37dBu
In the similar procedure to the above, select the "TEST
CASE:#5" and press "ENTER".
Input Frequency Input Level Specified Output Level Permissible range
1kHz -46dBu
84
Output Level Permissible range
(Reference Value)
+14dBu 0.05% or below
+22dBu 0.02% or below
+14dBu 0.05% or below
+14dBu 0.05% or below
+4dBu +4±2dBu
+4.5dBu +4.5±2dBu
+4.5dBu +4.5±2dBu

2-1-2-5 Phantom DC Voltage Test

Measuring Method
· Short-circuit a "+ terminal" and a "-terminal" of CHn,
and connect a 10kΩ load between the "-terminal"
and a "GND terminal".
· Press "ENTER" to return "TEST CASE No. Selection
Mode" for a time.
· Select the "TEST CASE:#6" (see 2-1-2-1 Diag Mode
Settings), and press "ENTER".
· Measure DC voltage difference between the "-
terminal" and the "GND terminal" of CHn. (n=1~8)
Permissible range
DC 33~36V
Press "ENTER" to return "TEST CASE No. Selection
Mode" for a time.
Select the "TEST CASE:#7" (see 2-1-2-1 Diag Mode
Settings), and press "ENTER".
After turning the PHANTOM power "OFF," check that
the voltage difference between the "-terminal" and the
"GND terminal" decreases immediately.
2-1-2-6 Analog CH 1-8 IN → CH 1-8 OUT
(Test at WORD CLOCK "INT 48kHz")
Measuring Points···Analog CH 1-8 OUT
Measuring Method···Input an analog signal from CHn
input, and measure an output signal from CHn output.
(n=1~8)
a. Characteristic Test at HA-GAIN: MIN (HA-GAIN
setting = "10dBu")
Enter the Diag Mode, select the "TEST CASE:#7" (see
2-1-2-1 Diag Mode Settings), and press "ENTER".
(If this setting is performed at the measurement in the
section 2-1-2-5, this setting can be omitted.)
q Total Harmonic Distortion
Input Frequency Input Level
(Reference Value)
1kHz +20dBu
20Hz +20dBu
20kHz +20dBu
w Noise Level
Measuring Method···Terminate the CHn input with
150Ω. Measure noise levels output from the CHn
output.(n =1~8)
Permissible range
-82dB or below
Output Level Permissible range
+14dBu 0.02% or below
+14dBu 0.02% or below
+14dBu 0.03% or below