Linnies, need your help...

I recently purchased a used LP-12 which came with a Troika mc cartridge. The cartridge wires seem permanently attached to the cartridge body and connect to pins located at the headshell-arm tube junction. Don't most cartridges have pins on the rear of the body that attach to wires protruding from the arm tube? I want to replace the cartridge but it seems that this configuration is unique. Perhaps I should just get the Troika re-tipped. Any advice/info would be appreciated.
You can replace the Troika quite easily. To use a new cartridge, you can get headshell leads (basically little wires with a clip at each end) to connect between that new cartridge and the tonearm. Most places that sell cartridges also will sell these leads. The wires that you see on the Troika are basically a set of headshell leads which are permanently attached to the Troika. This was a design feature--Linn claimed it gave better performance by reducing the number of connections and solder joints in the signal path.

In addition, you can have the Troika rebuilt. I believe that Linn offers this service. (See their web, then click on "How to Buy Linn" then "Linn Direct." for details). Rebuilding the Troika may be a good choice. It was once top of the line, and some people consider the Troika to be the best cartridge ever for the LP12. Others, of course, think otherwise.

Good luck!
Jc2000 said it all -- i.e., no problem there. Just to add that IMO, you could consider investing in upgrading the LP12 &/or arm to latest specs (if it isn't already), and keep the Troika (retipping, depending on wear). The Troika is, indeed, one of the best sounding cartridges for the traditional LP12 configuration and easy to set up, too: I expect it'll keep you happy -- it's a very musical TT combo!
One point that I should have made in my last post is something you may already know. When installing a cartridge on a Linn tonearm, the tonearm should be removed from the turntable when tightening the cartridge's bolts. If left in place, the arm's bearings could be harmed. You may know this, already, but I thought I should mention it--better to be safe than sorry....