Yamaha MU128, Руководство по обслуживанию

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MU128
22
Distortion factor 0.25 % or less
When A/D INPUT VOLUME is set at minimum, make
sure that the specified value shown below is obtained
for OUTPUT (R).
OUTPUT (R) : -72 dBm or less
Set A/D INPUT VOLUME at maximum. When the
inputting the sine wave data -9.0 dBm and 1 kHz in
the AD INPUT (L) field, make sure that all the level
meter lamps on the LCD are lit.
Ending the test
Press the [ENTER] button. You will then go to the
next test.
18.
DSP AND DRAM
18 DSP & DRAM
Measure the frequency, waveform and level of
individual signals output from the OUTPUT (L, R)
terminals and make sure that the
proper
signals are
being input. Before starting the measurement, make
sure that the plug is not inserted into the AD/ INPUT
terminal. Also set the master volume at maximum.
Observe the situation for at least two seconds.
Check items
OUTPUT (L) : 1 kHz +/- 3.0 Hz, Sine wave,
+3.5 dBm +/- 2 dB (Load: 10 k ohm)
Distortion factor 0.25 % or less
OUTPUT (R): 1 kHz +/- 3.0 Hz, Sine wave,
+3.5 dBm +/- 2 dB (Load: 10 k ohm)
Distortion factor 0.25 % or less
Ending the test
Press the [ENTER] button. You will then go to the
next test.
19. CHECKING THE 128 SIGNAL SOUNDS
19 128ch OUT
An audible
signa
l is produced for channels
1 to 64
from
OUTPUT (L) and for channels 65 to 128 from OUTPUT
(R).
The audible signal is produced 64 times for approximate
0.3 seconds at intervals of approx. 0.1 second.
Make sure that the proper audible signal is heard for
each of the 128 channels. Also make sure that the
sine wave being output has the proper waveform.
(L ch = 1 kHz, R ch = 2 kHz)
Before starting the test, set the master volume at
maximum at the time. During the test, the following
information will appear on the LCD:
19 128ch OUT
Lch=xx Rch=xx
(xx : Channel number with the audible signal
being produced.)
Ending the test
Press the [ENTER] button. You will then go to the
next test.
20. PB1 NAME
Note 1: For test 20 to 23, connect the PB (plug-in board) to
the CN 5 of the DM sheet in the equipment before
turning ON the equipment.
20 PB1 NAME
A request for the board name and version is sent from
the MU to the PB
through the MU-PB communications
signal line. The information obtained from the PB is
th en di splay ed on the LCD. Ma ke s ure that the
communications signal line for the CN 5 of the DM
sheet
is
functioning properly
and
check the board
name and version.
Displaying the test result
OK
20 PB1 NAME
PLG100-(VL) VX.XX
(X.XX = Version number)
NG 20 PB1 NAME
err
(If no information is returned from the PB.)
21. PB1 RAM
21 PB1 RAM
Check the RAM of the PB connected to the CN 5 of
the DM sheet.
Displaying the test result
OK
21 PB1 RAM
ok
NG 21 PB1 RAM
err
22. PB1 MIDI IN
22 PB1 MIDI IN
Check the MIDI IN of the PB connected to the CN 5 of
the DM sheet.
Use a MIDI cable and connect the MIDI IN A (Rear)
connector to the MIDI OUT connector. Then conduct
the test.
Before starting the test, select MIDI under HOST SELECT.
Displaying the test result
OK
22 PB1 MIDI IN
ok