Go to ground zero and start over without making the system so complicated. Unbridge the amp to eliminate that wiring as a source of failure. I would take out the ICBM and the sub for starters and hook up the speakers to make sure the Russound amp is fine with your speakers. You probably blew some fuses in the down channels. If I am reading your post correctly it sounds like you are feeding the output of the Russound amp to the sub input. Normally powered sub inputs are not amplified before the sub. I would think the sub outs from the ICBM would go right to the sub, not to the amp. Connect the sub to the main sub output and test to make sure it works correctly. I would then connect the sub very carefully per the manual. Make sure all your connections are clean and keep the volume way down. Test the system with the ICBM out of it.