Brutus 1206D started squeaking (like a bird) today

My Brutus bxi1206D started making the sub squeak today, in a way that I've never heard a sub/amp make noise. It's not a whiney ground issue, I've had those before and this sounds nothing like that. This time you can see the woofer cone shake in and out slowly and the sub literally sounds like a squeaky door opening and closing or a tiny bird chirping. Also, if you turn up the volume it still powers the sub fine, but it makes that squeaky noise.

I opened it up and replaced a few leaky capacitors, however, that did nothing to alleviate the squeaky noise. I looked more closely and found a lead on one fet that wasn't even soldered! wow! So I soldered that and it still squeaks.

Any thoughts? Thank you!!
 
With both unplugged, there is no noise. It also increases linearly with volume; to a certain extent and then plateaus. I didn't think of plugging one in at a time.

I also tested it on my bench to eliminate issues related to the car/wiring and it does the same thing running on a power supply at my work bench.
 
Perry, I believe you've solved this one for me before.

This sounds like the same issue I had with a 1206d, the sound it produced sounded like an Atari and if you push on the sub by hand with the amp turned on it sounds like the coils are rubbing except that it was "squeakier" than normal coil rub. When I opened it there was no drive signal to any outputs.

If that's the case it may be Q11 or nearby resistor on the driver card. In my case it was a 270ohm smd resistor tied to Q11.
 
Now that I think about it, my issue may have been Q11 AND the resistor because blindly replaced Q11 first, when that didn't fix it I found an open resistor tied to it.

As a side note I'm not sure if unplugging the RCAs would've stopped the noise on mine but I could see how a small amount of signal could make the problem apparent. I took it straight to the bench and saw no drive signal so I had no need to feed a signal into it at that point.
 
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With the amp powered on with no RCAs connected, push on the sub with your hand. Does it sound like it's rubbing? Turn off the amp and push on the sub, is it no longer "rubbing" or squeaking? Plus when you play music it sounds VERY distorted. Those are the exact symptoms I was having and if it's what you are experiencing then I'm 99% sure it's Q11.

3/4 the way down the board from the power terminals (near the RCA jacks) is the audio driver board. It's soldered in vertically, Q11 is in the upper left. I believe it is a MMBTA42, it's marked 1D.

The 270ohm resister was just below that, don't remember the board designation but it will have 271 written on it.

If you confirm that all is well with the RCAs I would recommend just blindly replacing Q11 and check to see if any nearby resistors are open as well but it may just be the Q11 transistor.
 
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