Here is the latest progress. I have been taking advantage of summer to do outdoor things, haven't given up on the radio.
I put the tuner unit back together yesterday and today. Overall my method is: take it apart as much as i can, clean everything up, re-assemble with as many original parts as possible but don't go overboard using old parts if they are not good enough.
So turns out that hot zinc dip was probably not the best idea. Many threaded holes and tight clearances needed to be cleaned up to fit, that took a lot of time with files and sand paper and thread chasers. The movement should operate easily without any oil when all the parts are clean. Once it's together you do oil it and then it really gets smooth.
There was a lot of taking it apart to re-assemble in a different order. I should have made a few more notes about the disassembly order.
I am posting only photos from the successful order-of-assembly path. This means i have a fewer images to share, but on the plus side, when you look at any of my photos you will see a partially assembled state that should not require any disassembly if you reproduce that specific state during your work.
Attached photos: - tuner unit chassis - how to compare button return springs, I discovered that the earliest versions of this radio used substantially weaker button return springs. - weak spring vs newer stiffer spring, my springs got mixed up, but putting them back to back we can clearly see a difference in compression. - installing the buttons, us an alligator clip to temporarily hold them in place - all buttons installed
The button retaining part had a soft rubber strip on it that cushions the buttons return and prevents rattling on metal. I have replaced it with adhesive felt. It is a bit difficult to see in the photo, but there is a felt on both edges of that retaining part that the buttons extend through.
When using non-automotive grade self adhesive felt, i go around the edges with a dab of crazy glue to ensure the low quality adhesive won't let go.
second post with more pictures to follow shortly -s
