Seeking schematic - DCM Loudspeakers Sub2 - B&K Components 8/12/92

Hello! This is a bit of a message in a bottle, but here goes: I am looking for a schematic for a sub amp board.

The subwoofer was built in Ann Arbor Michigan by DCM Loudspeakers. The Model is: Sub2.

The board inside is labeled:

(C) B&K Components Ltd
8/12/92

So, yes, that means old... but before it developed a problem the two sub speakers (one downward, one forward firing) used to sound wonderful.

Now, with just power applied, it sounds like a Harly-Davidson popping.

I would like to take it in for repair... but a schematic will help the audio tech troubleshoot.

If anyone knows where I might get a copy of that B&K schematic, i would really appreciate it.

Thanks!