Hello Mark,
 
those switches are the Q-switches. One dedicated to each filter. They are two position ones, with off being up and down being on; when on, the q-switch gives you about 8 db of boost at the cutoff frequency you select on the filter.
 
The dimmer should be inside the electronics cavity.
 
Valentino

Valentino,
 
Thanks for the reply!  That clears most of it up.  I am still foggy on the function of a Q-filter.  I have heard of the term but cannot find any technical info.  Is it a range of frequencies boosted or is there any actual filtering as the name suggests?  Is there  a cutoff frequency selection found in the electronics cavity?
Mark

Mark; a good discussion of the filter and Q switch can be found here:
http://club.alembicguitars.net/Images/393/7213.html

The little trimpots in the cavity are for gain only, won't affect the sound at all. The dimmer is usually a large silver pot (which is actually a Series I volume pot that failed noise tests, but still works as a variable resistor just fine).  
 
Feel free to write or call me for more details.

Thank you for the explanations!  I can see the whole picture now!
Mark

It?s been a long time but I finally got around to opening the rear electronics cover and I do not see a dimmer pot for the LEDs.  I only see a fixed resistor on the LED switch.  Is it possible some basses are shipped without a dimmer pot ? or am I just not seeing it?  If there was one there, would it be connected in series with the fixed resistor?
Many thanks!
Mark

It's more than possible, many do. If you post a picture of the electronics cavity, I can confirm for you. It is usually a big silver pot, close to an inch in diameter. I'd be surprised if you missed it.
 
I can get you details and materials to add it if it was overlooked.

 
Hi Mica,
I apologize for being so slow to reply (I had to find out how to compress photos)
Here's the electronics - the upper left blue resistor looks like the only current limiting resistance for LEDS that it has.  It would be very nice to be able to dim now and then   What do I need?
Many thanks, Mark

Mica,
 
Would it be possible to obtain the missing LED pot and installation instructions?
 
Many thanks,
Mark

Sure thing! Send me an email with your shipping address, and I'll mark the photo with instructions and send you the pot. If you have any  questions after you get it, let me know.

Thank you Mica!  I sent an email with my address on 11/16/2006 - I hope I sent it to the right address.
 
Mark

Hi Mark - yup, I got it in both places. I'll gather up the goods and ship to you early next week.

Many many thanks, Mica!
 
Mark