Damper, Switch, and Pedal Connections Don't Work.

Discussion relating to the Korg M3 Workstation.

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Kckelly54
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Joined: Thu May 14, 2020 6:14 pm

Damper, Switch, and Pedal Connections Don't Work.

Post by Kckelly54 »

I have a M3-61exb. I had a touch screen failure. Had it replaced a year ago and everything seemed fine until I noticed the Damper is not working. I checked the polarity and it was correct. I even bought a new Korg DSH1 with no luck. I then used my EXP2 in the Pedal Port with no effect. I then tried a momentary switch with Switch port with no effect. All my other rear connections work fine.

Is there a fuse with those ports? Anyone have any ideas?
HardSync
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Joined: Fri Jan 07, 2011 6:18 pm

Post by HardSync »

Don't know if you have got this fixed yet. I don't think there is a fuse for those connections. The most likely culprit is a disconnected cable to the PCB that holds those three jacks. Because in order to get to the screen and replace it, that board has to come out.

If you're comfortable opening up your M3, you can check all of the cable connectors to that PCB to ensure they are seated properly. These are quite fiddly though, and you have to be really careful when sliding them off and back in. You don't want to break the wires that are attached to the connectors. If you're uncomfortable doing that kind of work, then you'll have to take it in for repair again. Perhaps you can call the service tech who replaced your screen and explain what's wrong, and hopefully they'll fix it for no charge, but I wouldn't count on it, as it's been a year already. It's also possible it came loose from the keyboard while it was being moved/transported... maybe... But my guess would be that it wasn't properly connected after the screen was replaced. Or it might be a broken 12v power wire, too... Honestly, the only way to know is to open up the unit and have a look.

Here are some photos of the internals of the M3: https://www.personal-view.com/talks/dis ... korg-m3/p1

The photo you want to take a close look at is this one: https://www.personal-view.com/talks/upl ... 91f4e0.jpg

Good luck, and I hope you get this fixed. :)
alland
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Location: Estonia

Post by alland »

If you are sure that just all three dmper/switch/pedal input jacks not functioning and only those, but anything else in input sections is working properly (sliders, encoders, buttons, tempo knob etc), then only common element for those inputs is 3,3V power on JackA PCB (KLM-2644).
From there Damper and Assignable Pedal goes to Panel R (KLM-2648) where there is common A/D converter shared also for encoder (big dial) and Tempo button. Assignable Switch however goes almost directly to CPU digital input.
3,3V power is pretty common amongst many components, so probably no power unit failure but something with JackA PCB or with connectors. JackA gets its 3,3V from Function PCB (KLM-2642) CN2-5.
Added: For testing this 3,3V failure hypothesis - "Input overload" signal comes from input opamps similarly to sw/pedal/damper signal and should also be affecteb by the same fenomenon, but I am not quite sure how you can test that...
Korg KronosX/Pa4x/M3 • Ableton • Komplete • Omnisphere • Roland Cloud soundcloud.com/allandd
Kckelly54
Posts: 3
Joined: Thu May 14, 2020 6:14 pm

Post by Kckelly54 »

[quote="HardSync"]Don't know if you have got this fixed yet. If you're uncomfortable doing that kind of work, then you'll have to take it in for repair again.

Thanks for the response. Great idea. I opened her up and checked all the connections that I could easily get to. No Luck, but worth a try.

I'm going to touch base with the guy who did the screen repair and see if he'll trouble shoot it.

Thanks again for your input.
KC
Kckelly54
Posts: 3
Joined: Thu May 14, 2020 6:14 pm

Damper, Switch, and Pedal Connection Follow-up

Post by Kckelly54 »

Yup, it was a cable connection that wasn't seated properly during the screen replacement. Thanks for all the input. $80 and I'm content... :D

KC
HardSync
Platinum Member
Posts: 849
Joined: Fri Jan 07, 2011 6:18 pm

Re: Damper, Switch, and Pedal Connection Follow-up

Post by HardSync »

Kckelly54 wrote:Yup, it was a cable connection that wasn't seated properly during the screen replacement. Thanks for all the input. $80 and I'm content... :D

KC
Great that it is fixed. :)
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