I fixed it. I desoldered all the diodes to the knobs and added them back one by one. It was a faulty trigger level knob. I unsoldered the knob and took it apart. It seemed ok. I put it back and now it is working again.
I wrote this here so If someone else will have the same problem. Unsolder all diodes and put them back one by one and test the knob that have the diodes back. It will stop working and you will know which one is it.
Post time 2020-10-10 17:00:50