Board repair for subwoofer

How loud do you listen? Do you run demanding levels of EDM music or are you more geared to average listening levels or perhaps classical? Point is you may not need 850 watts of power and can save a bit of $ by downsizing. What size is the driver? What ohm?

@gdaddy1 

I listen to only classical and jazz, and any acoustic music, but at realistic listening volumes.  I think that it’s a few vinyl records that I play that have a low rumble that causes the amplifier board of the subwoofers to detonate.  They are the Martin Logan Balanced Force 212 subwoofers, which have 2 12 inch woofers (drivers); RCA impedance is 10,000 ohms.

Disconnect that board and throw it in the trash.

Call it a passive sub and run it with an external amp such as this one from fosi audio, might be good enough.

https://www.suncoastaudiodirect.com/products/fosi-audio-tp-02-tda7498e-subwoofer-amplifier-receiver-mini-hi-fi-class-d-professional-integrated-amp-for-sub-bass-shakers-220w?_pos=1&_psq=Fosi+tp&_ss=e&_v=1.0

@deep_333 

A problem is that there are two drivers, each with an 850 class D amplifier, in one sealed cabinet.  I would need to get two 850 W amplifiers on the same signal from the pre-amplifier, or some satisfactory combination that could drive both woofers from one RCA line.

You can find plate amplifiers from Dayton at Parts Express or fancier Hypex models at Madisound and miniDSP.  besides physical fit and power I encourage you to get something with good DSP capabilities so you can properly tune the sub.  If you are inexperienced, stay away from Hypex as their software is a PITA and stick to Dyaton or miniDSP.