In June, I tuned-up a Challenge 21MP for Andrew Huot at Big River Bindery in Davenport, Iowa. He also has an Asbern ADR-1 that had a gummed up oscillator. I hadn’t serviced one before, so this was a great opportunity to see what it’s innards look like. The main difference is the crescent is set into a collar that is attached to the end of the tube at with socket head caps screws.
