Nord User Forum

I've had numerous dirty contact issues with my 5 year old NS2 since I've had it, which I fix myself in most all cases. Recently however I've had 2 notes that exhibit uneven velocities when I play them (these notes go from quiet to loud too quickly). I assumed it was a damaged rubber contact (as in the past) so I replaced with new ones last night. I've discovered that when the rubber gets tears in them, the velocity levels are affected. Oddly enough, they are STILL not acting right regarding the velocity levels even with the new rubber contacts I put in last night. Being my Nord is fairly old, should I replace the actual contact board underneath - or whatever it's called?? If that is worn out would that cause the uneven velocities?? I love my Nord, but this is driving me cuckoo.
Thanks !

Please define what you mean by "uneven velocities":
Does the problem note velocity (MIDI) change each time for the same physical key press velocity or do these two problem notes' velocities just differ from neighboring (normally behaving) keys?
Do they appear to be giving faster than expected velocity, slower, or random?

Possible causes differ depending on the answers, so I recommend taking no action until you clarify this.

You seem technically adept (having made these repairs yourself): --If we see need for further analysis, do you have access to any electronic diagnostic equipment (e.g., ohmmeter, oscilloscope)?

Thanks for your response pterm. What I mean by uneven velocities is when I play from light to hard, the midi velocity # jumps too quickly to the higher values. It's not egregious, but definitely not as even and uniform as all other notes. I've had this problem before and the cause was a torn rubber contact. I'm rather mystified because I assumed replacing that contact would've solved it. I forgot to mention that I run my Nord into Mainstage, so I can see the exact midi velocities as I play. And no, I don't have any diagnostic equipment.

reinski wrote:What I mean by uneven velocities is when I play from light to hard, the midi velocity # jumps too quickly to the higher values.

The Nord determines the velocity by measuring the time difference between closing the two contact pads under the key .
To me, this means something is delaying the signal from contact closest to the rear of the Nord or advancing the front-most contact closure.
The likeliest cause (and easier to check) is a mechanical one. Some ideas:

1. Check if the new rubber contact section is properly seated (are the alignment tabs fully in their respective holes) -- if misaligned, it could distort the rear contact puck higher than normal so it takes longer to close that switch.
2. Is the new rubber section rotated to the correct orientation - the pictures I see online show different shapes over the front and rear contacts, so if in backwards, might cause your symptoms (although I think this would affect more than two keys so it seems unlikely).
3. Is there any damage or distortion to the problem keys' plastic "plungers" (the plastic parts of the key that presses the rubber contact locations). --Compare to good keys.

I just reread the original post. Since you say this existed before you replaced the rubber, item # 3 seems the most likely mechanical cause.

Yeah, I'm thinking it's issue #3. The new rubber contacts I put in a couple days ago looked OK to me, but truth is they might be slightly damaged. I assumed they were brand new but they were given to me and maybe they were actually used. Of course for me to check this out it entails taking the keyboard apart again. I have a whole new set of rubber contact strips on order which should be here in a few days. Hopefully that will remedy everything. Once again I appreciate your input.

It remains possible that an electrical fault or degradation causes this issue, but without diagnostic equipment I see no way to isolate the problem.

Could it be worn-out on the board side? (where there the rubber bubbles make contact)

There are two sides to the contacts: rubber strip and circuit board. Usually this issue is remedied by cleaning both surfaces. Torn rubber strips suggests that someone is banging too hard; tears are not common.

IT DOES NOT MAKE SENSE TO REPLACE RUBBER STRIPS ONLY. I encountered someone recently who spent ~$70 on a new set of strips. Entire assemblies, PCB and with pre-mounted strips, are (in the US) available through me at ~$110 including shipping. Why pay $70 to do a half-assed job when kicking a few more dollars in will provide completely new contacts?

Again, this is usually remedied by simple cleaning...but you did say that you've cleaned the contacts several times. Eventually you will arrive at the point of diminishing returns. If there is any copper peeking through the black ovals on the PCBs for ANY note(s), the PCB is toast and needs to be replaced. There is an enterprising person who once posted a solution whereby one could purchase some special stuff for repainting/carbonizing those black ovals, but that's seriously tedious work, the stuff is horrendously expensive and also extremely toxic; not recommended.

Save yourself the hassle and replace the contact PCBs; return the order of rubber strips. Contact me at work if you wish to order parts.

pablo.mastodon@americanmusicandsound.com