OK since people wanted to see them here are some shots of how I 'fixed' the rotary encoder pots on my oscilloscope. Hopefully it's not too many pics or too large.
1. After removing the top cover this is the control board on the front of the machine.
2. I removed this little daughter board. It came right out.
3. I then removed four phillips head screws with a small screw driver.
4. That free'd up the board from the chassis. Now I had to remove two flat flex cables to get the board out.
5. There was one at the bottom. I used a small flat head to push the connector free.
6. And another one at the side of the board.
7. Here is the top and bottom of the board.
8. The idea is to take apart the rotary encoders for cleaning. They consist of a shaft, a contact plate, a shell and a mounting plate. The mounting plate is soldered on to the board (two big solder pools) for stability but you do not have to remove it. You just need to desolder the three pins that lead to the contact plate (at one end and between the two big solder pools).
9. I used an iron and solder sucker to desolder the pins.
10. Then I turned the board over and used a small flat head to very carefully bend over the four straps that hold the encoder to the mounting plate. They bend easily so be careful.
11. Then the encoder (except the mounting plate) should pull right out.
12. Here is the encoder from the bottom. I sprayed it with Deoxit at this point.
13. Then I carefully removed the contact plate from the shell.
14. The shaft will also come out at this point. My pots were loaded with a greasy oil that I cleaned off of everything with paper towels and Q-tips.
15. I then inspected the contacts to make sure they were sticking out at this angle and lined up closely enough. They need to be at this angle to ensure contact with the metalized surface on the bottom of the shaft. Be very careful.
16. After reassembling the encoder and placing it back into it's mounting plate, I carefully bent the four straps back over to hold it together. Be careful here as well but make sure you get the straps bent back so that they hold everything firm.
17. Then solder the three pins back on and you are done.