Yamaha MU128, Service Manual

MU128

20

9.

MIDI 3 B

Use a MIDI cable and connect the 

MIDI IN B connector

to the MIDI OUT connector. Then perform the test.
Before starting the test, select MIDI under HOST SELECT.

09  MIDI 3 B

The test pattern (AA 50 5F) will be sent from MIDI
OUT and received by MIDI IN B. The result of the test
pattern received will then be judged.

Displaying the test result
OK

09  MIDI 3 B
                              ok

NG

09  MIDI 3 B
                              err

10. MIDI 4

Use two MIDI cables and connect the MIDI IN A (rear)
and MIDI IN B connectors to the MIDI OUT and MIDI
THRU connectors respectively. Then perform the test.
Bef ore s tarti ng th e tes t, s elect  MIDI t he H OST
SELECT.

10  MIDI 4

The test pattern (AA 50 5F) will be sent from MIDI
OUT and received by MIDI IN A. The data output from
MIDI THRU will be received by MIDI IN B. The result
of the test pattern and data received will be judged.

Displaying the test result
OK

10  MIDI 4
                              ok

NG

10  MIDI 4
                              err

11. HOST SELECT

11  HOST  SELECT
Mac   ZZZ-YYY=  XXX

(ZZZ=Lower limit, YYY=Upperlimit, XX= Measured
value)

Change MAC over to PC-1, PC-2, and MIDI in
sequence under HOST SELECT in accordance with
the host name displayed on the LCD and make sure
that the switch is functioning properly.

Displaying the test result
OK

11  HOST  SELECT
                                  ok

NG

None

12. TO HOST TX/RX

12  TO  HOST

The test is for factory inspection before shipment.
The test will not be performed here.
Testing without a test-specific jig will result in an error.
To eliminate any error, refer to "B. Starting the tests."

13. WAVE ROM

13    WAVE ROM

Read and verify four WAVE ROM data through SWP30.

Displaying the test result
OK

13    WAVE ROM
                              ok

NG

13    WAVE ROM
        IC xx              err

(xx : IC number with an error)

14.

1 kHz OUTPUT (L) sound

14  OUTPUT  L  1 kHz

Make sure that the proper signals are being output
from OUTPUT (L) and PHONES (L).

Note 4:

Insert the plugs into the OUTPUT (L, R) and PHONES

terminals and measure the frequency, waveform and level of
individual signals output. Before starting the measurement,
make sure that the plug is not inserted into the AD/ INPUT
terminal. Also set the master volume at maximum.

Check items
OUTPUT (L) : 1 kHz +/- 3 Hz, Sine wave,

+3.0 dBm +/- 2 dB (Load: 10 k ohm)
Distortion factor 0.25 % or less

OUTPUT (R) : -80 dBm or less
PHONES (L) : 1 kHz +/- 3 Hz, Sine wave,

-4.0 dBm +/- 2 dB (Load: 33 ohm)
Distortion factor 0.5 % or less

PHONES (R) : -65 dBm or less

Ending the test
Press the  [ENTER] button. You will then go  to the
next test.