Korg EX-800 Service Manual

8. TROUBLESHOOTING TABLE
The order in which things should be checked naturally coincides with the signal path in the POLY-800. Please refer to this
flow chart to help you pinpoint sources of malfunctions. Remember to save user programs to tape before beginning service
procedures.
No sound or other
malfunction.
Try loading data
from accessory tape.
Check +5V
(No. 15),
-5V (No. 16)
supply voltage {No. 13,
16) for ±5V.
Is tone
generator (IC3) output
correct?
Is waveform ^\ NO
synthesizer circuit (No.31)
output normal?
Is the correct
signal being input at
VCF (IC1)20and21
pins?
Check connector
CN-61 pin. Is VCF
output present?
Check ^
to^see whether EG controL
^signal is being input pro-
Check No. 31
circuit IC,
block resistors.
Check analog
switch circuit
(No. 28).
Check IC 1
(NJM2069).
Replace.
Is EG S/H circuit-^YES
No. 20) getting correct
input?
Replace IC12
(HD14051).
YES
CheckTGIC3
(MSM5232).
Replace if
necessary.
Check master
oscillator cir
cuit (No. 19).
Check KLM-598 compressor/expander
IC(IC3), BBDIC(IC5),etc.
The problem is probably in this circuit
board.
The problem is in the main board
(KLM-596). Check CPU, I/O, RAM,
ROM, etc. control lines and address
and data buses for problems.
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Korg EX-800 Specifications

General

Brand	Korg
Model	EX-800
Category	Synthesizer
Language	English