Hey guys and gals, I do electronics repairs for the company I work for in addition to being a show and events tech, and am having a problem with an Ashley EQ and wanted to bounce the issue off of some of you techs that have bench diagnostics experience... It is an Ashley two-channel rack mount 31 band EQ. Inside of the box is four boards total that interface each other on ribbon cables. There are two boards mounted to the back panel and two boards mounted to the front. The rear boards are I/O boards, and the power supply is built onto the Ch2 lower rear board. The front boards have the actual slide potentiometers and likely do all of the actual processing. The problem I'm facing is that both channels have an intermittent self noise that is very distracting, both when hooked up balanced and unbalanced. I say intermittent because it will test fine in the shop, even after many hours of use, but once it's taken to a customer site it will act up again. Granted I have been able to make it act up in the shop but it comes and goes, and not on any definite time interval. Channel one is better than channel 2, as ch2 is almost unusable with how much noise it imparts. It's a very smooth white noise sounding sound that doesn't vary much. An increase of EQ gain increases volume of self noise. The bad news is that this EQ has been dropped repeatedly - I keep telling some of the techs I have to work with that dropping gear is bad but to no avail...anyway once when the unit was dropped I opened it up and both of the ribbon cables connecting the I/O to the front boards had dislodged along with the safety fuse. Reconnected everything and found the self noise. Also when I tore the unit completely apart once I found a structural solder trace that helps hold the part of the board where the slide pots are to the processor part (perpendicularly) had broken and pulled its trace off of the board. It does not, however, appear to be electronically relevant and does not have continuity to either ground or hot rails (on either end of the joint). Any ideas as to what specific component this problem could be attributed to? My theory is that it has to be something in the power supply, since it is the only thing that relates the two channels together or it is an identical problem with an identical component common to both channels, that would have sustained damage during the same event. Thanks.