I have an old 12" Sunfire True Signature Subwoofer from 2002. Sunfire will not repair this because it is too old so I am looking to repair this myself if it is salvagable. I have a mysterious problem that I'm hoping someone on the forum will have experienced before that can help point me to the problem component. The problem is that I have an 80 hz harmonic at lower volume levels.
My example source is the initial track of Dark Side of the moon. The heart beat runs at 40-60 hz but I also get a big pop at 80 hz at every beat. The magnitude of the pop goes down as the input signal increases so it is pretty intermittent overall - but very annoying.
So any thoughts on whether the amp may be doing this or whether I have a driver gone bad?
As an update to this, I was able to do the circuit board repair based on other information on the web - several capacitors had gone bad. To avoid the problem in the future I had to upgrade this to dual PSA XV15s and have retired the sunfire to my PC. Anyone with some patience should be able to complete this repair the same way I did
There was a workaround suggested to short two pins on an IC to avoid the power save feature - I do not recommend this as it appears to have made my sub perform worse.
I went through the capacitors listed with a capacitance meter and found several bad caps - got them from Mouser and I've been up and running ever since. I fortunately did not have issues with any other components on the board