Harman ST-5 Turntable RabcoTonearm and Cart

All,
Very new here so sorry for a somewhat basic question.  I did some google searches (found the manual for the HK ST-5) and searched this forum but did not find exactly what I am looking for.

I just picked up an ST-5 and knew it was going to need some work.  The cartridge is an Ortofon LM 10 but it looks like it is broken.  It is just a rectangular tube with "LM 10" on it and a tapered metal extension without a stylus protruding from the front.  The "neck" which attaches to the tonearm is not there and the red wire seems to have broken off from the clip.  I thought I could detach the tonearm to have a better look because in the manual it looked like I could do that.  I unscrewed the knurled nob where it meets the main assembly and I thought I could just pull the tone arm off the socket.  Instead, the aluminum tube came out but what looks like a sheathed wire stayed attached to the base of the tonearm assembly.  So my questions are:

1. Should I be able to detach the tonearm?  Can I just gently work the sheathed wire off of the main assembly on the turntable?
2. Now that I take a closer look, it seems only the green wire is still attached to what remains of the cartridge.  Is it easy to just strip off some insulation from the broken wires and resolder the clip or is it better to try to replace the entire wire assembly? (If easier to replace, can anyone suggest some sources?)
3. Is the cartridge itself broken or is the "neck" and stylus just additional pieces that are easy to purchase?

Thanks for any help and info.  I don't dabble that much with vintage equipment (or any equipment all that much, my current turntable is a Technics SLD2) and this was a bit of an impulse buy for me.  

Thanks!