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It was more work than I anticipated, but I think it turned out well. I replaced all the knobs that had chips in them and did the volume output mod while I had the chassis out.
One last thing I'm still planning to do is to convert the loop to series. BUT, I'm trying to keep the amp as much in the spirit of the original as possible. So I'm thinking I will get creative and do the loop mod by changing the mix pot to a 5-way rotary switch where far left is loop bypass, far right is series fx, and the 3 in-between positions are 25/75, 50/50, and 75/25 splits using resistors.