Audiophase CD188 stereo modification

[SpeakerBoy 64]

The stereo i currently own is an Audiophase model CD188. I opened it up today to get back a screw for my glasses that fell in through the cd tray, and while i was looking around i found three knobs on the main circuit board; little small metal cube with a circle cutout on top, with a colored knob inset inside. Being as curious as i am, i was about to start messing with them but thought i'd ask what they could do, before i blow something up.

Note: i googled the model number and brand and only got two results.

One is blue, one is orange, and one is yellow.

i cant the friggin usb cord for the camera so no pics for now.