Hi Jogen, The only thing I can do is to replace the input pot…. if the imbalance is very bad then this will fix it, but the tracking on the input pot is always a problem.
If you would like me to look at it then please send it to me at the Sound House. With all these JoeMeek units I charge a flat fee of £25 plus the cost of returning the unit.
I can’t guarantee to fix everything, but if it’s fixable, then there’s a good chance! 
Ted