The pins of the connection from input output board (1 to 6) to the A/D Board are shorten to the back casing.
Isolating the caseing in this area whith tape solved the problem.
nice mixing everyone
(pictures come later)
My board started doing this a year ago on 2 channels. I thought it was the mics, then compression or a setting. Then cables or receivers. I opened up the m20d and sprayed contact solution on the ribbon connectors and re-seated them. Worked great for about 3 months, now it is doing it again on 4 channels. 3 mic channels and one line in acoustic guitar channel. What to do what to do.