R3 - Mod wheel changes pitch, unwanted effect

LOW.Z · Post by **LOW.Z** » Fri Feb 04, 2011 1:44 am

My mod wheel is having an unwanted effect on many patches, raising the pitch a full step as well as the effect it previously had. It does not happen on all patches, one example being "Arp Organ", the mod just changes the "rotary" effect, as it should.

Has anyone observed this change, any ideas how to correct it?

xmlguy · Post by **xmlguy** » Fri Feb 04, 2011 6:36 am

Find a program that does what you say, then examine the program with the software editor.

X-Trade · Post by **X-Trade** » Fri Feb 04, 2011 8:42 am

In the programs where it does not have any effect, is the pitch wheel bend range set to zero?

robert_hirst · Post by **robert_hirst** » Fri Feb 04, 2011 11:10 am

I have this same problem crop up intermittently and it is a hardware fault - if you clean the pots for the mod and pitch bend wheel it seems to get rid of it for a while for me. My suspicion is that it is a grounding issue between the 2 pots which occurs when the resistance in one of them becomes higher than normal due to being dirty or worn. The ultimate solution is probably to replace the pots, but I have so far not been able to locate identical ones - the nearest I've found are some Alps ones on Farnell which are linear 10k and the same shaft size I think, but not the same size connection points. the other thing I had considered was sticking something like a 10k resister between the 2 pots to see if that would elimate the crossover, but have never got round to trying that so far.

LOW.Z · Post by **LOW.Z** » Fri Feb 04, 2011 3:51 pm

I plugged a Roland EV-5 expression pedal into the "pedal" jack, and the mod wheel functioned properly again. I hope it's not a physical defect, seems not as the effect was not consistent across all patches. Weird, random problem, which are the worst kind, hope it does not return.

Thanks for your comments

X-Trade · Post by **X-Trade** » Fri Feb 04, 2011 6:57 pm

It is a hardware fault, most likely, but I can't remember the most typical cause.

Basically the mod wheel (or sometimes one of the knobs) is interfering with the pitch wheel's voltages.

robert_hirst · Post by **robert_hirst** » Mon Feb 07, 2011 10:24 am

I had this problem (again) over the weekend, and just before a gig aargh!! Interestingly I tried the suggestion from above about plugging a sustain pedal in and bingo the problem disappeared! I still think there is some sort of grounding problem there with the mod wheel, but possibly plugging in the pedal allows some sort of ground discharge. I am also wondering if part of the problem I have is to do with the case I use - it's a custom made hard case with a faux-fur lining, but I think is is possible the material is causing a static built up whilst the R3 is in the case, as when it does occur it always seems to be after I've stored it in the case for a day or two - never after it's been left out on the stand for a few days - does this seem possible?

axxim · Post by **axxim** » Mon Feb 07, 2011 7:57 pm

robert_hirst wrote:I had this problem (again) over the weekend, and just before a gig aargh!! Interestingly I tried the suggestion from above about plugging a sustain pedal in and bingo the problem disappeared! I still think there is some sort of grounding problem there with the mod wheel, but possibly plugging in the pedal allows some sort of ground discharge. I am also wondering if part of the problem I have is to do with the case I use - it's a custom made hard case with a faux-fur lining, but I think is is possible the material is causing a static built up whilst the R3 is in the case, as when it does occur it always seems to be after I've stored it in the case for a day or two - never after it's been left out on the stand for a few days - does this seem possible?

Even if I don't have the R3dias schematics, it could be that the jack for the sustain pedal has built an interruptor that is normally closed and opens when a pedal is plugged in. This is similar to some amplifiers that disable the output when a headphone is plugged in. As all the potentiometers and controls (even the pedal) are multiplexed for sampling with an A/D converter and depending on how they are tied together, it could be that such closed interruptor oxidates with the time causing a bad connection. When a pedal is plugged in, this interruptor opens and maybe from the friction with the plug and the closing, when it is removed, makes a better contact again removing the issue at least for a short time.
I remember somewhere at this forum people having similar intermitent issues with the Line outs after connecting and disconnecting some plugs.

LOW.Z · Post by **LOW.Z** » Thu Sep 01, 2011 4:54 pm

I am having this problem again, with no change when I plug in either sustain or mod pedal. Any other suggestions before I open it up and try to clean the pots?

stopi · Post by **stopi** » Sun Oct 23, 2011 6:36 pm

I had this problem too and some more problems:
- vocoder microphone working only when he wants (low quality plug)
- not both audio outputs sometimes working
- selecting patches sometimes work crazy - I can't rotate 360 degrees, only part of patches (e.g. half) is possible to set

Modulation wheel is detuning almost 1 semitone up (!).
It appears suddenly, sometimes after power on. It appears with no any sound changes, on any patches. I think, the main problem is that this Korg is "Made in China". It's low quality of manufacturing.