The manual can be found here. Note which manual to use by the serial number of your unit.
Summary of DIP switch settings
1 ON lowers the frequency of the low range (only).
2 ON lowers the frequencies of low and high ranges.
3 ON increases the sensitivity of the envelope generator to all but the quietest part of the input signal.
4 ON greatly increases the sensitivity of the envelope generator to the loudest part of the input signal.
5 ON increases the response of down-drive.
6 ON enables the low-battery light to function as an sweep-limit indicator.
I had one.
Main complaint... The on/off button was intermittant.
I didn't think it sounded bad, and liked the DIP switch mods.
The unit takes alot of heat for not being a true clone, and apparently bad blood between the new/old owner of the patent (I'm not sure I have the story straight here, someone else might chime in).
In the end, I did what the original designer reccomended and sold it and got an original MuIII (the guy I sold it to fixed the button and says he loves it for Pedal Steel, which is what I used it for at the time).