If the clip just broke off from the wire, the fix should be easy. First, get a soldering iron and remove the remnants of the old wire and solder from the clip's eyelet. Have someone hold the end of the clip with a needle nose pliers, but don't damage the clip. If you broke the clip at the wire termination, you can still solder onto the clip, on the outside of the center piece.
After that is done, fix the clip. I'll ass/u/me that is was too tight? Then try to spread the two leafs of the clip apart a little. Use another cartridge pin as a gauge to check.
If you need to trim some wire off of the lead, that will be a tricky part, I'm hoping there is a little wire left for you, otherwise, this will be a bitch, but you can do it.
The other thing that you could do it solder a short piece of wire to the clip and solder the other end to the clip with the white wire. These are both connected to the RCA shields (also part of the coil loop) and are connected together in the preamp anyway. That could be another fix, and way easier. Always use a needle nose to put on the clips and don't force them. If the clip is too tight, spread them apart a bit.
Wayner