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7. TROUBLESHOOTING CHART
Note:
Before servicing, make sure that all harnesses are plugged into their connectors.
Problem:
Bad LED
indication
Bad MIDI scale.
FREQ, INT
doesn't work.
Check KLM-829
power supply and
confirm proper
± 15V and +5V
voltages.
Trouble is in IC1,
IC2 (±15V), IC3
(+5V), fuse, diodes,
transformer, AC
cord, power switch,
or KLM-833 power
supply line.
Refer to KLM-833
clock adjustment
procedure and
check if clock is
normal.
NO
Check reset circuit.
When power is
turned on: low
to high level;
low is active.
Check IC24,
Q23, IC22, IC23.
Check IC23
x1,x2
terminals.
Check x1, IC23
C71,C72.
YES
Follow
adjustment
procedure.
Check IC53,
IC55, IC21,
IC22.
Does oscilloscope
show normal
waveform at IC23
INT1, INT2
terminals?
(NOTE)
WAVEFORM AT DELAY SETTING.
Check IC20
1-pin (S/H)for
ormal input.
Trouble is in IC26
IC27, IC28, IC23
IC22, etc. Check
each chip and bus,
in turn.
Trouble in
IC23 or IC20
Check
IC22, IC20
INT1
INT2
SH
n_TLTL
5V
OV
L
5V
OV
6.4ms
U
LI
5V
-21-
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