Knob not changing value

gauthier · Posted: Tue Sep 20, 2016 1:54 pm Post subject: Knob not changing value

I just acquired a Nord Modular Keyboard with expansion, everything seems in order but the knob 4 doesn't seem to process change of values.

In a patch, I've assigned knob 4 to some parameter, when on the synth I switch to "Edit" mode and touch knob 4, I see the parameter name displayed (it means it detects me tweaking it), but no matter how I turn it, the value will remain where it is.

The fact that it detects the knob (I see parameter name reflected on display) and the fact that the associated led is lit makes me think that I might have some other setting interfering but can't figure out where, or maybe the knob is just faulty?

I've checked the general knob mode setting is on "Normal" and I've tried the "Hook" mode as well.

Anyone encountered this? what is recommended course of action for me to get this fixed?

Thanks.

blue hell · Posted: Tue Sep 20, 2016 2:16 pm Post subject:

hi gauthier, welcome

and it works with any other knob, right? In that case the knob would be faulty I guess.

gauthier · Posted: Tue Sep 20, 2016 2:28 pm Post subject:

Hi Blue Hell, yes I can use all the 17 other knobs without issue when they are assigned in the current patch.

It is strange that the display shows the parameter name of knob 4 when I tweak it (like it does for other knobs) while it doesn't change the value at all.

blue hell · Posted: Tue Sep 20, 2016 2:43 pm Post subject:

Yes, that is a bit strange indeed. To my knowledge there is nothing in the settings that would cause one particular knob to be inhibited, so I'd think it to be failing anyway.

There is a voltage over the potentiometer, and the wiper causes a fraction of that voltage to be sent to an AD converter, the digitized value being used to set the parameter. Maybe there is just a tiny bit of variation in the signal coming in, just enough to be seen but not enough to change the value. I'd expect the converter to have 10 or 12 bits of resolution, while the parameter would have 8 .. hmm or 7 prolly ... at most, so there would be some room for a change too small to change the parameter to be seen still.

How are your electronic skills?

gauthier · Posted: Tue Sep 20, 2016 2:50 pm Post subject:

Blue Hell, thanks that's interesting never thought about the details that far down the potentiometer alley Smile

Regarding my electronic skills, they are as bad as my skills to deal with modular synthesizers: pretty bad, but I could try to grab a volt meter and try to figure out if I can compare with what is happening on other knob at some point.

I'm not in a hurry as I just got the synth and I can work around the issue in several ways, but definitely worth gathering info I'll need to get this fix without spending too much $.

Thanks again!

blue hell · Posted: Tue Sep 20, 2016 2:54 pm Post subject:

Ok, happy knobbing for now then!

And feel free to ask for more help.