Korg DSS-1 - Problem 2: Mode Progression Issues; Problem 3: Switch Input Issues; Problem 4: GET Operation Issues

I PROBLEM 2,
The indication in Fig. 1 appears but fails to progress to
the indication in Fig. 2.
There is trouble in CPU 1 (KLM-780) or TG (KLM-782).
Which one the trouble is in can be judged by replacing
each circuit board in turn with a good one.
If the trouble is in CPU 1, it is necessary to check the
CPU, ROM, RAM and TG interface.
If the trouble is in the TG, check according to the follow
ing procedure.
i 1
Remark:
The steps up to here do not determine which part of
a circuit board is bad. Replace KLM-782 (if neces
sary return it to KORG).
i
• Check KLM-782 connector CN12-9 with an
oscilloscope.
Is CN12-9 at "H" level?
YES
NO
L
Is a 20 MHz clock input to
PIN 1 ofGA-I (IC11)?
YES
Are connectors CN10 (data
bus) and CN11 (address
bus) inserted correctly?
YES I
Is the KLM-782 power sup
ply normal?
±12V, ±5V
It is possible that there is
trouble in IC58, IC63, etc.
is possible that there is
trouble in the time base
NO I module.
Noi
Insert connectors CN10 and
CN11 correctly.
NO^
There is trouble in the load
circuit drawing power from
power supply circuit KLM-
786 or KLM-782.
IPROBLEM 3
The indication does not progress from Fig. 2 to Fig. 3 or
Fig. 4 (switch input is not received).
The trouble could be in the CPU 1 circuit board
(KLM-780) or the panel switch circuit board. Check the
switch scan circuit in IC14 (8255) on KLM-780 and the
connected harnesses and connectors.
IPROBLEM 4
GET is not performed normally, or while GET is in pro
gress an error message appears or the indication re
mains stuck on Fig. 5.
The trouble could be in the KLM-780 FDC or FDD.
Perform the FDD test which is described separately.
If there is trouble in the FDD, replace it with a good
one. Check the KLM-780 FDC referring to p.46.
60
Scan by Manual Manor
http://www.markglinsky.com/ManualManor.html