Electronic Creations Co. one tube wonder phonograph

[comradesvox]

Hi. I am working on restoring an old "one tube wonder" phonograph for my dad. The only brand name I see on it is "Electronic Creations Co." It uses a single 25L6GT tube with the 90v motor in series with the tube filament.

I already replaced the electrolytic filters. I am attaching photos. I still have pretty low volume and get mechanical humming when using 33 or 45 speeds. From what I can tell I need to do at least the following:

1. Replace the selenium rectifier with a modern diode and appropriate ballast resistor. If you look at the photos it seems there is already some sort of ballast resistor in series with the selenium rectifier but it reads pretty low (don't remember right now).
2. Clean/lube the motor and replace grommets.
3. Replace the cathode resistor. It is reading about 230 ohms but I was told by forum member radiotvnut that it should be 150. If you look at the photos you will see that the stripes are pink, green, pink - so I guess with age what I am seeing as pink bands are really supposed to be brown.
4. Volume pot is intermittent - needs cleaning.
5. Wax/paper tone cap needs replacing (haven't got to it yet).
6. The difficult part - he also advised that most likely the crystal cartridge is going bad. Part number is MT-14 and it is a dual "flippable" cartridge (78 and LP). Not quite sure how to proceed with that - radiotvnut points out that I need 3v to drive the power tube and these cartridges are no longer being made new. I really don't want to get into building a preamp stage but if I get a lower voltage cartridge just MAYBE I can build out a single-ended op-amp preamp with a voltage gain of maybe 2 or 3? Getting the proper DC though would involve a voltage divider so to keep things simple I would like to avoid this.

In any case, I just figured I would throw these ideas out. These one-tube record players are new to me. I have worked on old tube radios before, and old analog organs/amps from the 60s, but never something like this.