I got a good deal on a "non-working" Tektronix SC504 scope. It was very dirty, missing the front shield that covers the tube (both a filter and protection for the user), and it had some broken knobs as well.
I was able to clean it fairly well. The main bezel around the tube has some worn off paint I will likely sand and repaint.
I was able to super glue the Volt/div knob for Ch1 after removing the broken piece of the shaft using a carefully bent coat hangar.
I got a new blue filter/shield from Sphere. I also got a new knob pair for the intensity and focus controls.
The fiberglass shaft for the focus pot goes all the way from the back out through the center of the intensity pot shaft (which is hollow) to the front of the instrument. This shaft had broken off at the tip, and there was nothing extending out past the end of the intensity pot shaft (which is hollow). With nothing sticking out there was nothing to which to mount a replacement focus knob. These knobs are on the top left of the unit face.
See below for fix, but I cut the shaft and spliced it with some vinyl tubing. This let me slide the front part of the shaft forwards and back out through the hole to mount the new knob.
There is an internal switch to switch between using the timebase vernier as a variable timebase like most scope have, or instead as a variable Hold Off. Someone had left the switch right in between the two settings which meant it would not do any horizontal sweep at all. I fixed this, and cleaned all the pots/switches as well.
I am pretty excited to have this little 80 MHz dual trace scope working again. It even supports true X-Y!
Here you can see the output of my recently restored Wavetek 145 20MHz Function/Pulse gen. The top trace is obviously a sine wave, while the bottom is the pulsed Sync output, which I am using for triggering. The scope also has an external trigger I could use instead, and a button that lets you view whatever waveform is being used for triggering.