Roland A-70, Service Manual

Page: 17 / 27

A-70
Sept, 1997
(If there is a problem, check the items of check 1.)
ê
This completes the bender/wheel test.
Action :
check 1 :
BENDER <=> PANEL L BOARD CN708
PANEL L BOARD IC705, 707
PANEL L BOARD CN705 <=> MAIN BOARD CN11
MAIN BOARD IC7
check 2 :
WHEEL <=> PANEL L BOARD CN701
PANEL L BOARD IC706, 707, 708
PANEL L BOARD CN705 <=> MAIN BOARD CN11
MAIN BOARD IC7
7 : MIDI test
I1 I I2 I O1 I O2 I O3 I O4 I
(1) (2) (3) (4) (5) (6)
Summary : Test the operation of the MIDI IN, OUT, and THRU jacks
Procedure : Press numeric key 7 to enter the MIDI test item.
ê
Use a single MIDI cable to connect IN2 and OUT1, and check that display items (2) and (3) change
from “-” to “0”.
ê
Use another MIDI cable to connect IN1 and THRU, and check that display item (1) changes from “-” to
“0”.
(If there is a problem, refer to check 1.)
ê
Leaving the IN2/OUT1 MIDI cable connected to IN2, connect the other end of the cable successively to
OUT2, OUT3, and OUT4, and check that display items (4), (5), and (6) change from “-” to “0”.
(If there is a problem, refer to check 1.)
ê
This ends the MIDI test.
Action :
check 1 :
JACK BOARD Q110,Q111,Q112, IC101, 102, 103
JACK BOARD CN102 <=> MAIN BOARD CN4
MAIN BOARD IC11
8 : N.C.
9 : Keyboard test
Summary : Test keyboard and audio signal operation
Procedure : Press numeric key 9 to enter the keyboard test item.
ê
Press a desired key and check that the key number, on-velocity, and off-velocity are displayed correctly.
Check that the piano sound appropriate for each key is output.*
(If there is a problem, refer to check 1.)
ê
Apply pressure to a desired key, and check that aftertouch changes in the range 0 to over 6(See NOTE1).
(If there is a problem, refer to check 2.)
ê
This ends the keyboard test.
* If a VE series unit is installed in the A-70 and the OUTPUT jack is connected to an amp, a piano sound will
be heard.
Action :
check 1 :
KEYBOARD <=> MAIN BOARD CN2,3
MAIN BOARD IC1
check 2 :
KEYBOARD <=> AFT BOARD CN402
AFT BOARD CN401 <=> PANEL L BOARD CN703
PANEL L BOARD IC706, 707
PANEL L BOARD CN705 <=> MAIN BOARD CN11
MAIN BOARD IC7
9 : Audio signal output test
Summary : Check LINE-OUT (unbalanced L(MONO)) etc.
Supplementary explanations (functions) :
* Line out impedance :
1680 ohms
L(mono) impedance : 840 ohms
* If a plug is not inserted into LINE OUT R, the L and R channels will be mixed and output from LINE OUT L.
This is referred to as L(MONO).
Procedure : Turn off the power, and install the VE-GS1 into the A-70.
ê
Enter test mode, and press numeric key 9 to enter the keyboard test item.
ê
As shown in the following diagram, press the TRANSPOSE, MONO, or PORTAMENTO keys to
output a sine wave from LINE OUT.
The following table shows the values that should be detected. Check that the oscilloscope shows a
clean sine wave, and that the wave height value of each waveform is correct.
(If there is a problem, refer to check 1.)
17
Switch operation
TRANSPOSE MONO PORTAMENTO
output a sine output a sine output a sine
wawe from wawe from wawe from
LINE OUT and LINE OUT and LINE OUT and
PHONES OUT PHONES OUT PHONES OUT
L only L and R R only
`
press
`
press
`
press