DBX 160XT Microphonic Problem (Solutions?)

I've mentioned before about how my ancient DBX compressor has gone microphonic over the years and will pick up CB truckers and stuff. I'm wondering where the problem is at within the unit? If I knew what was causing it then I'd have a better idea of how much it would take to fix it. I can tell you that it will do it with any cable. I've tried everything from Pro Performers to Monster cable. Actually it seems the most quiet with a really old Switchcraft stereo insert cable I have. Any ideas what component in the DBX unit is microphonic? I've never heard of one doing this before mine. It was a very expensive compressor and I'd like to fix it at some point if the cost is reasonable, or if I can do it myself.

The only component that will exhibit this type of behavior would be a vacuum tube. If the dbx has tubes, replace them.

This advice applies only if the unit is truly "microphonic". It could be that "microphonic" is not the right term, if what you're experiencing is actually RFI from a grounding and/or shielding issue. In that case, you'd best hand it over to a competent technician to troubleshoot.