[Solved] MidTom section not working

Hi,

I have built the Nava 1.02, everything is working except the midtom section. It does make some noise, at least the oscilator seems to work (reacts also to pitch potmeter). But it's overal output is very quiet, it seems to me that the envelope(s) isn't working correctly. In the audio fragment I have placed a note on step 1 of the sequencer. As you can hear it also has a very long decay.

Also VR15 is behaving really change.. (as you can hear in the middle part of the audio clip), only the first few millimeters are making a difference in sound, everything beyond that makes pure noise.

I checked all the components, AFAIK everything is mounted correctly. I suspect IC23 (m5218l) being faulty, does that makes sense? I also did notice a visible anomaly at this IC (see photo #1). I think this component was already this way when I received it, because I noticed it already during the build itself.

Any suggestions?

Photos:
https://imgur.com/a/S8nHcvH

Audio:
http://portal.studiorepairservice.nl/midtom.wav

Happy new year & kind regards,

Bastiaan

Considering the behaviour of VR15 and it being connected to IC23, a quick check would be to swap out that 5218 with one from another instrument.

So I swapped the m5218l with the one of the hi-tom section. The mid-tom section now works, so the problem was in fact IC23.

Case closed.