Joseph, it’s unlikely that there’s anything wrong with the old SC2 V1.05 other than wear in the input gain pot…. that’s the most common cause of unequal gain in the channels. This was particularly so with the ‘Omeg’ pots used at the time (easy to identify…. take the knob off and look at the shaft, if it’s black plastic, it’s an ‘Omeg’.) Later units used ‘Alpha’ pots which are superior.
It’s true that some LDR cells do deteriorate with time, but in the SC2 version 1.05 I remember we used a type of cell that is well sealed and I have not found one ‘aged’ yet.
Back to gain shifts…. this is a constant problem with all 2-channel systems; the accuracy of the pot tracks has to be VERY good to meet a criterion of even plus or minus 1dB. The old ‘Omeg’ pots had backlash between the tracks and were notoriously poor in this respect.
Yes, I do have stocks of the parts for the SC2, but not those input gain pots, we now use ‘Alpha’ pots and switches.