Turbosound

Everyone should know the level of ineptitude that exists in this company. I have been trying for nearly 4 months to simply order replacement parts. I was just informed via email that they were never ordered! I have been without an entire touring system for months because of this issue and now this! As an industry veteran of over 35 years, I have never encountered a company who cares any less than this one. it's really quite pitiful!

I have a Turbosound ip 1000 that has been carefully used, never beatup or pushed to a clipping point. 
Recently, I've got a hissing, static noise from it and I can completely turn the volume down to MUTE and the hissing persists. At full volume the hissing is about the same. 
I've hit the terminals with electronics cleaner to no good result. 
This unit has no firmware or capacity for it. No USB input, so it's not firmware.
Thoughts?

So here is our setup,  2- TBV118L-AN subs (4 total) stacked on each side of the stage being run aux fed. There's an xlr coming out of the aux on our Midas M-32 going into an xlr splitter box to split the mono cable into two xlr cables going to left and right stacks. The issue is you can hear alot of subs on each side but it pretty much disappears in the center. Almost like a phase issue we had a long time ago with our old passive system where one side of the subs had the + and - wired backwards causing the subs to cancel each other out in the middle. But I don't see how that could be the issue here with xlr closed system all the way?