Shruthi 4 Pole Filter Modes not responding - SOLVED

This is the third Shruthi I’ve built, and I’ve never had any issues in the past. I built this 4 pole, and everything seems to be workign ok, with the exception that when I go into filter and try to change the filter modes, I hear no change. I do hear a change in the resonance modes when I change that value from Liquid to wobbly to ms, but not when I change from LP4 to anything else. Any ideas?

Is the 1x6 connector inserted between the two boards?

Absolutely. There is some wiggle room vertically between the boards, but not too much, and moving it up and down doesn’t fix the issue.


You’ll have to probe the 74hc595 on the filter board. Can you observe voltage changes on its pins 15, 1, 2, 3, 4, 5 when you change filter mode?

Please post a picture of your board.

Probed the 595 and it came up intermittent, so I removed the chip and re-soldered my IC socket. Must have been a bad cold solder joint that I couldn’t see, because now it works. I used blue LEDs and they are very directional, so I need to resolder the LEDs.
Thanks so much!