That is not a desirable result!  Thanks for this.  Maybe I'll sell for parts or see if as you suggest there's a dumpster dive for me on eBay.

Not knowing how this player is build... If you already know that cartridge is ok and you have multimeter to measure resistance. Just take the cartridge out and I assume you see connectors. Then in the other end of arm must be wires coming out. Are they visible ? Might be 4 of them. Measure resistance of all of them, the correct wire shows 0 oHms if it is ok. Check those wires like that, you shoud get 4 results with 0 oHms. Do also crosscheck that the wires are not short circuited.

Ismo

I disassembled the top and took a look at the tonearm.  The wires from the arm to the 8005073 Board (Muting PCB4) are solidly connected.  Upon further look it seems the break(s) are likely at the head, where the black plastic cartridge receptacle meets the metal tonearm tube.  When I touch it there's a gap that easily forms so my guess is the wires are severed at the head. 

Pictures attached.

Pic of wires attached to pcb

Tonearm receptacle "gap" where wires likely broken??

How do I remove this from the metal tonearm? Heat gun and slight tug??

It is possible that someone may have tried to remove the cartridge by “unscrewing” it thereby stressing and breaking the connections at its socket. This would be evident if the junction of the black holder and arm tube were loose. Assuming one can remove the holder, I am not familiar with how the wires were attached as I’ve never attempted this type of repair. B&0 only offered the arm complete as a part. 

Don’t bother trying to repair vs, replace. Note the sonic weld along the sides. Likely the connector was first wired and then the halves welded. Unless the break occurred downstream from the connector you are out of luck. The only safe way to check is to totally free up the other wiring end giving it a few inches of slack before attempting to remove the mount making sure you label the wires. Heat is a problem as you can easily melt the plastic. Careful rotation may be the better choice to break the glue seal but it’s hard to prevent torquing the arm bearings and holding such a thin-walled tube without damage is no easier. While you technically have “nothing to lose”, unless it is already free to rotate, I don’t see a path to success. Perhaps there is someone who has done this, but I would not have attempted it when I was a tech. 

Don’t bother trying to repair vs, replace. Note the sonic weld along the sides. Likely the connector was first wired and then the halves welded. Unless the break occurred downstream from the connector you are out of luck. The only safe way to check is to totally free up the other wiring end giving it a few inches of slack before attempting to remove the mount making sure you label the wires. Heat is a problem as you can easily melt the plastic. Careful rotation may be the better choice to break the glue seal but it’s hard to prevent torquing the arm bearings and holding such a thin-walled tube without damage is no easier. While you technically have “nothing to lose”, unless it is already free to rotate, I don’t see a path to success. Perhaps there is someone who has done this, but I would not have attempted it when I was a tech.