I replaced the 3-section electrolytic and all the paper caps. Also, two way out of tolerance resistors.
Next, I popped the tubes back in and did a slow power up while monitoring the B+ voltage. The loop antenna is integral to the cabinet so I just clipped in a short test lead. After fiddling with the controls, I heard some familiar local stations
Next up, I'll clean the scratchy controls with DeOxit, slide it back in the cabinet and use the proper antenna. I'm also going to replace the 6K6 output tube which tested borderline good.