I've really got to get rid of those stickers.
This kit came in pretty unloved condition, and much of the hardware was poked. Still, the brain works fine, though the "mix" knob was broken off, and the headphone and mix output sound like arse. I figured it was time to put my electronic engineering training, and ready access to tools at my work to use, and refurbish this beast during my lunch breaks.
A very dirty, dinged up SDS 9 brain.
First up, I had to take it apart. I took lots of photos while I did this to make sure I could remember how to put it back together.
I then vacuumed out as much dust as I could.
Below left is the broken mix output knob. Notice how it doesn't have a "shaft" like the one on the right.
This was about all the time left in my lunch hour, though still had enough time to carefully give the faceplate a scrub with some good ol' detergent and water. Next up, soldering in a replacement potentiometer and testing.