Crumar Musical Instruments User Group.

Hi, I'm new to this group and was hoping I could get some advice from 
the community:

I have a rather beat-up Trilogy that I've been tinkering around with. 
It has some problems that I've been working around, but I was hoping 
someone here would know if there's anything I can do to fix it 
without paying more than I spent for the machine (which was very 
little).

The string sound works beautifully, but it has problems with the 
organ and synth sounds.
With the organ sound, it makes a popping noise at the beggining and 
end of each key press.  The sounds are fine so long as you always 
have one note going, so I can work around that problem to some extent.

My main problem is with the synth sound. The volumes on some keys are 
significantly lower than the rest, most notably the D, E, and A flat.

I'm crossing my fingers that different volumes for each note is some 
adjustment I could quickly change inside the machine, but I rather 
suspect that getting this corrected will be costly.

Thanks for any help or advice!