Doepfer

I did a search of the database and didn't see anything describing this.

I just got a used a-132 dual voltage controlled amplifier.  The upper VCA is functioning properly.  The lower VCA is not working properly.  It has a very low output and "thumps" or "pops" when it opens/closes no matter what signal I use to open it.  There's a very large difference in the upper and lower channels.  

I was passing audio through it and opening it with an LFO.  The upper channel behaves as expected but the lower does not with the same signals.  

I also have another A-132 and both channels function very similar and are similar to the upper channel on the problematic module.

Anyone have any ideas where to look for the problem?