Dsp Check; Tuner Function Check - Korg A4 Service Manual

<7. DSP CHECK
>
(1) Here,
the main
board's DSPs
(IC10,
IC11) and
D_RAM (IC15,
IC16) are checked.
(2)
Connect the oscilloscope
to the rear panel OUTPUT, and turn the
OUTPUT volume
to MAX.
(3)
Press [WRITE], and the check will proceed
as
shown
in
the table below.
Confirm that the waveform
is
the
same as that
shown
in
the figure.
DISPLAY
A4
GTR(B)
OUTPUT when no good
P4-1
DSP
(KLM-1597 ICll)test OUT
L
Check IC11
and analog circuit.
P4-2
DSP
(KLM-1597 ICll)test
OUT
R
Check
I
Cl
1
and
analog circuit.
P4-3
DRAM(KLM-1597
1C15,
16)test OUT
L
Check
IC11,
IC15 and IC16.
P4-4
DSP
(KLM-1597 IC10)test OUT
L
Check IC10 and 1C11.
P4-5
DSP
(KLM-1597 IC10)test OUT
R
Check IC10 and IC11.
Figure
1
(4)
When the checks are completed, press [WRITE] to
proceed to the
next check
item.
<8. TUNER FUNCTION CHECK
>
(1)
Here the TUNER function
is
checked.
Connect
the rear panel INPUT jack to
the oscillator.
(2)
Set the INPUT
volume and
OUTPUT volume
on the panel to MAX.
(3)
Input a
short wave 27.5Hz/10mVp-p
to the INPUT jack and
confirm that
the
TUNER LED
0
(green) on the panel lights
up.
(4)
Input a
short wave 2093.005003Hz/10mVp-p to the INPUT
jack and confirm that
the TUNER LED
0
(green) on the panel lights
up.
A4
GTR(B)
TUNER Function
27.5Hz
/10mVp-p
2093.
005003Hz/10mVp-p
TUNER <0>
lit
TUNER <0>
lit
(5)
When this check
is
completed, press
[MODEA]
to
proceed
to
the next item
to be checked.
16