PCB-Stability?

Hi

I have made me some PCBs of which one is simply a collection of potentiometers, switches and LEDs. Now when I simply press on on the PCB or bump it, some potentiometes "react"

i have made a little vidèo (values change on .. yeah.. on what exactly? - YouTube).. you can see that I press on the faders-shell and on the display some potentiometes react.

how can I get rid of this? why is that?

There are a number of possibilities I can think of:

  1. Bad or loose connections. Not likely based on what is see in the video.

  2. Most likely is the introduction of electrical noise from your hand to the potentiometers.

Try lightly holding onto on of the pot (metal) casings with one hand then tap with your other hand. Does it react the same?

Also try to tap on the board but instead of your fingers use a pen or plastic ruler etc. I'm not sure a pencil is a good choice as the graphite conducts.

John

Well, you would always have the faders grounded by their mounting tabs, wouldn’t you?

Certainly the case with audio pots and just as likely in this situation.

Support the board better - it shouldn’t be able to wobble about with such a small push .

how about a wide angle still shot

Is it a mulfunction of the slider pots? Dooes their resistance vary when shaken?
Cneck it out with a multimeter. …

Tell us about that dispay that has the glitch.