Andy, one of the things I remember from my days of vacuum tube amplifiers was the ( I think) fact that replacing one multi cap with several individual axial leaded capacitors did not give as good a common mode noise rejection. In other words I might not totally eliminate the hum only reduce it. Then I would not know if I had actually cured the problem or merely shifted it. Hence my quest for a tech with actual experience on that particular instrument. From what I remember most of the power supplies of that era was of a design called a "pi" filter with some additional bypass caps and ripple filters. The caps were built into one case to reduce ripple and hum. Essential for sound equipment but nice for other stuff. This organ instrument power supply has two cans.Not just one like I remember. One of them being negative common case and the other positive case. In this particular circuit one cap is 2000 uF and three being of 1000 uF value. Negative case. The other capacitor is positive case and onecap value is 1500 uF the other being 500uF. All voltage ratings is 35V DC. The positive case is a surprise to me. I only worked on sound equipment as a hobby. I built my first stereo system system from parts scrounged from the trash bin and 17 inch Admiral B&W TV when I was 15 years old. Lacking schematics I had a lot of trouble getting the components values right. But by picking over the junked chassis in a radio TV repair store; I eventually figuered out which tube related to what function and then copied the parts assemblies associated with each stage. But AC hum was always a problem. On a TV you got dark band creeping across the screen and with sound amplifiers By the time I finished school and was actually working in the electronics industry things had shifted to solid state components and we were working on digital circuits.