pioneer head unit blown?

I'm not a pro with car audio but i do all of it myslef, and on a very tight budget. i have a older pioneer supertuner D head unit, pioneer 4x6's in the front, and pioneer 6x9's in the rear, with a total of 5 bargain subs-2 pioneer premier IMPP 12"s in a ported homemade box, with a mitzu 2000w 4ch amp, both subs bridged. One  pioneer cheapo 12" i got in a trade, a 10" visonik i got at wal-mart, both hooked up to a sentrek-480rms dual channel amp- and a 15" optimus bridged of a legacy 1000w 2 ch  amp, which gives me constant headaches. 

I have the mitzu on rca's, and the other two on "high-output" from the right-rear speaker. i had a bass-tester cd in and maxed out my amps, and think i fried my head unit. right in the middle of the tones it made a kind of "pop" and turned off my mitzu amp-it had lights and thermal protect on, but then i noticed the door speakers were acting goofy...popping and crackling-still reproducing the music, but my front-left speaker was not reproducing the mid-range, and the highs were very muted... i have a few problems with polarity,--old wires, but everything was fine before...

And the legacy and the sentrek both worked, sort of,  but the mitzu, when i pulled the rca's, made it seem better-but still broken. the speakers-with the rca's in the mitzu amp, picked up my engine whine and would pop and crackle on bumps... im very broke and i don't want all those subs to go to waste, i love my subs like children, and have become something of a conversation starter in my small town, please help!

Yes, a system like that is probably good for catfish.