Tony Sestito said:
-When you crank it, there's a distinct low-pitched hum you can hear through the speakers.
Hey Tony - know why it hums?
...
It doesn't know the words!
Has the volume changed over time? If not it just might be the output of the cartridge relative to the gain of the phono section. Might be totally normal to need to turn up the volume a notch.
Edit: Just reread your post and it sounds like it did change. Cartridge failures are rare, they're just a long strand of coiled wire, but it does happen. Are the channels balanced? I would probably start with checking the wiring from the RCA plugs to the cartridge connection pins, center pins and grounds, being careful not to do bad things to the stylus. The low output and hum might be due to a crappy connection. Assuming you have an ohm meter, also check the resistance from the center pin to outside ground. Should be similar, and you should find reference values on vinylengine.com
In reply to jwagner (Forum Supporter) :
I think my first step is to hose the cartridge wires down with some Deoxit. That stuff works miracles; it has saved a bunch of my stuff in the past. I will probably clean the RCAs too. They are hard-wired, so it might be a good idea to check those connections on the inside. Hoping it's just dirty connections.
Tony Sestito said:
This used to be a common scenario: in the 1970s or 1980s a young guy would buy some large, high quality speakers for their stereo system. Later, they'd meet someone and get married, and eventually their wife would decide those things took up too much space or didn't fit with the decorating scheme, and they would be relegated to the basement or attic. Eventually, the family would have a garage sale and the speakers would be put on the sale with a $10 or $20 price tag. I picked up a couple pairs of speakers that way, and since I'm single I decide the decorating scheme. 
This many years on, it probably doesn't happen as often anymore.
In reply to stuart in mn :
I don't know much of the history on who owned these ones, but they came in with a really junky Magnavox all in one stereo from the late 80's. It was one of those ones that looks like stacked components, but everything is attached. There was no way that thing could have effectively powered these speakers. So, I am guessing they did get relegated to garage duty at one point because 80's woodgrain was out of style in their fancy rich people house. 😆
