We have a Korg C30 that still sounds fine. But for as long as I can remember, the pedals (there are two) haven’t worked.
Anyway, if there are any pointers to what it could be or what to check inside (I’ve never disassembled it). I’m hoping it’s a “oh, sounds like you need a new such-and-such, here’s the part number!” But not holding my breath 
Thanks
Ken
Try this:
Remove the connector that comes from the pedal unit, then short out all the pins in the unit (no fear you can’t break anything). Now turn on the instrument and see it it works.
If it does work - then problem is in the pedal unit or the cable (the easier version) if it still doesn’t work then we have to have a closer look inside the unit.
But first thing first.
Thanks for the test procedure. To clarify, turn on the keyboard with the pins shorted (all of the connected to each other)? Should it sound normal or as if the pedals are engaged?
I’ll be back when I have results – thanks!
Ken
Should sound like both pedals pushed down
Ok. Finally got the instrument out of storage and tested it.
With all the pins shorted, the pedal sustain effect worked!
So it is either the cable or the pedal mechanism that is faulty.
What’s the next test to see if it can be isolated to the cable?
THANKS!!
Looks like the cable running through the leg of the stand to the base of the keyboard is continuous…
There are 3 wires (white, red, brown). Used an old ohm meter to test, and each was continuous.
This pedal stand has two pedals, left and right, no middle pedal.
On the base of the keyboard, when I short red and white pins, the sustain works. Shorting brown and white does nothing. (Nor does red and brown shorted). Unless one of these combinations is the soft pedal effect, and I’m just not noticing it.
So, either connectors are faulty (at the keyboard side or the pedal side). Or the pedals aren’t working.
Are the pedals just switches to mechanically short out the connections? Or is there a circuit board getting power that electronically does the work?
top side of connector wires from pedal stand
The square peg by itself is the brown wire endpoint
The square peg on the corner is the red wire endpoint
The round one is the white wire endpoint
Well, seems to be the pedal unit itself - common in many pedal units. They are very simple, but …
There is a little circuit board underneath the pedals - I suggest that some of the circuit board tracks have corroded. You have to take the circuit board out (may be a little tricky) and trace each track according to the little diagram above. If you find a break, use a piece of thin wire and solder bridge the break. If the break is underneatch the rubber contact then it may not be fixable that easy - if at all.
Okay, more testing.
The electronics work. If I press those rubber “buttons” on the board myself, they work.
So the shafts on the pedals just aren’t pressing them enough.
I can’t quite see how to adjust the pedals so that they press more. Or how to attach maybe a screw to the pedal shaft to extend it more (pic coming)
Here is with the pedal fully pressed. doesn’t extend very far to push the rubber buttons.
Though i see the potential issue of pressing too far could crack the circuit board.
Maybe if I could add a piece of foam to the end of the pedal part there. Or a small spring.
Take that rubber contact off - gently pull it off and then clean underneath with methylated spirits. Then put it back in. You need a soft wire that is not pointy so as to not puncture the that little leg (I use a 5W resistor - works perfect)
Then try again !!
To test a fix, I put double-stick tape on the end of the pedal part that should push the button. Then cut a small piece of soft foam and stuck it on there. It worked … extending the pedal “button pushing” part with a little bit of foam allowed it to push the buttons enough to work.
I’ll still do the cleaning maintenance you recommended. I have to disassemble again anyway to make a permanent fix.
Thanks
