Interesting indeed.
If one clock (CLK1) is working and the other is not then you should still hear one out of every two notes when in single mode. And when in double mode you should hear just DCO1 (which gets its clock from CLK1) while DCO2 would be dead (getting its clock from CLK2).
If you don't hear any DCO's at all (holding down eight notes for example) then check for write pules on MSM5232 pin 12. If there's no write pulse then check IC16 (40H32). You will most likely need a scope for that although a logic probe with hold mode can do the trick sometimes. And check for the ALE signal on pin 13. If there's no ALE signal then check IC27 (40H000).
If CLK2 is stuck at +5V then you will need to work you way back through the detune circuit (IC's 17 (40H074), 18 (40H000), 19 (40H151) and 20 (40H393).
These form a modulated phase shifter (thus detune).
Mike.
If one clock (CLK1) is working and the other is not then you should still hear one out of every two notes when in single mode. And when in double mode you should hear just DCO1 (which gets its clock from CLK1) while DCO2 would be dead (getting its clock from CLK2).
If you don't hear any DCO's at all (holding down eight notes for example) then check for write pules on MSM5232 pin 12. If there's no write pulse then check IC16 (40H32). You will most likely need a scope for that although a logic probe with hold mode can do the trick sometimes. And check for the ALE signal on pin 13. If there's no ALE signal then check IC27 (40H000).
If CLK2 is stuck at +5V then you will need to work you way back through the detune circuit (IC's 17 (40H074), 18 (40H000), 19 (40H151) and 20 (40H393).
These form a modulated phase shifter (thus detune).
Mike.