Just a brief update, I did have a look at the cartridge from the 50H, an ADC, and it was indeed miswired. I was able to correct that and tried it on the 750 and its working much better. It still has a bit of hum, but I haven't cleaned the contacts on it yet.
I'm also starting to think that my stylus is damaged on the Stanton cartridge. That would be sad as I think its an original stylus, which I gather are getting quite rare. I was already a bit suspicious as it seemed to be "riding low", with the body of the stylus holder just barely off the record. Looking at it, the cantilever also looks a bit crooked to me. I also have a fair amount of "woosh" noise that I though was still a motor or idler or bearing issue, but that went away with the ADC cartridge. I also felt like I was having to crank the volume up pretty high with Stanton, which seemed better with the ADC. I tried taking some photos of the tip with my phone, but they are pretty bad
. The stanton tip does look a little wonky to me though. I should be able to get a better look in the next week when we start getting our new lab at work set up and the microscopes come out of storage.
Here's the Stanton:
And here's the ADC:
With both cartridges still have some tracking/skipping problems, particularly near the beginning of records, so still have some work to do. I picked up a few clean records from a local store and the behavior is still the same, so I don't think that's it. I also ordered a couple brand new, but didn't want to play them until I'm sure my tips are ok.
Overall though I'm encouraged by how its sounding now with the ADC cartridge, which makes me think I'm getting close!
I did find a listing for the L piece that holds the spindle from a 10H, can anyone verify if they are the same? Maybe monk you can see if yours looks like the pictures of the 50H/750 ones above? The only thing that looks off is the brass piece sticking out at the far end from the spindle. Though I didn't disassemble mine that far, I'm not sure that but is the same. It seems like it would be much simpler to to just replace the whole part if I can find one than trying to repair the one that broke...
http://www.ebay.com/itm/332138477819?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT