What tomearm ?

mcmvmx

Do you know of a technician that does that ?

Steve at VAS in NJ. He's an expert, reasonably priced and usually has fast turnaround times.

@rossb , Excuse me, all 9" Pro-Ject and Rega arms have a spindle to pivot spec of 222 mm. I even think the hole is the same size but I'm not sure of that. 
MCMVMX , look for a used Rega arm. They are around. If you took the Pro Ject arm apart you should be easily able to put a Rega arm on. 
Hang in there,

Mike

I screwed up!! The Pro Ject arm spec is 212 mm. So, you would have to move the arm 1 cm away from the spindle. That is not too far and the base may cover the hole. It will work but you will have to enlarge the hole a bit.

If the OP cannot reassemble the arm or re-solder the wires I don't really  see how he is going to drill new holes in his plinth to install a Rega arm.  And that's assuming he wanted to in the first place. The Rega is not a drop in replacement, and as I said in my first response, the turntable would need surgery to accommodate it. It's not worth it and would look terrible, even if it could be done.

Sending the arm to a technician to reassemble is the most sensible option.

New Jersey is quite a ways from Mesa, AZ. Why not search for a more nearby dealer who would be kind enough to take on this job? I found this list of 10 places, not all of which are suitable but it’s a start, by doing a Firefox search:https://www.yelp.com/search?cflt=hifi&find_loc=Mesa%2C+AZ
Audio is a focal and local world.  One of the stores on this list may be able to recommend a repair person, even if they themselves cannot do the job.