Yamaha MU128, Service Manual

MU128

23

NG

22  PB1 MIDI IN
                                err

23. PB1 MEL

23  PB1 MEL

Perform the 

tests

 1 to 3 

described

 below and make

sure th at th e prop er signal is being output from
OUTPUT (L, R).
(Details)
The signal input into A/D INPUT is output from the

CN5-MEL OUT of MU128 and a request for the

audible signal is made to the PB. The sound source
PB then outputs a 1 kHz sine wave from MEL OUT.
The effect PB then outp uts the input signal from
MEL OUT. The MU128 then outputs the sine wave
input into CN5-MEL IN from OUTPUT.

1. Testing the MU128

Make sure that the MEL IN/OUT of the CN5 is
functioning properly.

2. Testing the sound source PB 

(PLG100-VL, SG, etc.)

Make sure that the sound source section and the
MEL OUT are functioning properly.

3. Testing the effect PB (PLG100-VH)

Make sure that the effect section and the MEL
IN/OUT are functioning properly.

Insert the  pl ugs  into  the OUTPUT (L, R)  and

PHONES terminals and measure the frequency,

waveform and level of each signal output. Set the

VOLUME and A/D INPUT VOLUME at maximum.

Check items
When the sine wave data---1 kHz and -15dBm---are
input into A/D INPUT (L), make sure the following
specified values are obtained for OUTPUT (L).
OUTPUT (L):

1 kHz +/- 3 Hz, 4.0 dBm +/- 2 dBm (PLG100-VH),
1 kHz +/- 3 Hz, 3.2 dBm +/- 2 dBm (PLG100-VL),
1 kHz +/- 3 Hz, 2.0 dBm +/- 2 dBm (PLG100-VS),
1 kHz +/- 3 Hz, 0.8 dBm +/- 2 dBm (PLG100-XG)

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

When testing the MU128, use PLG100-VH.

24.

PB2 NAME

Note 2: For tests 24 to 27, connect the PB to the CN4 before

turning ON the equipment.

24  PB2 NAME

A request for the board name and version is sent from
the MU to the PB through the MU-PB 

communications

si gnal l ine.  T he  in fo rma tio n  obt ai ne d f rom  t he
PB is 

then displayed on the LCD. Make sure that the

communications signal line for the CN 4 is functioning
properly and check the board name and version.

Displaying the test result
OK

24  PB2 NAME
PLG100-VL
VX.XX

(X.XX = Displaying the test result)

NG

24  PB2 NAME
                                    err

(If no information is returned from the PB.)

25. PB2 RAM

25  PB2 RAM

Check the RAM of the PB connected to the CN 4 of
the DM sheet.

Displaying the test result
OK

25  PB2 RAM
                                ok

NG

25  PB2 RAM
                                err

26. PB2 MIDI IN

26  PB2 MIDI IN

Check the MIDI IN of the PB connected to the CN 4 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

26  PB2 MIDI IN
                                ok

NG

26  PB2 MIDI IN
                                err

27. PB2 MEL

27  PB2 MEL

Perform the tests 1 to 3 described below and make
sure that the proper signal is being output from
OUTPUT (L, R).