Well, if you have the two places the spring attaches to both intact and if the arm pivots correctly, you could use any weak small spring you could fit in there, including a rubber band like the orthodontists use or one that you cut from a balloon or bike inner tube. It just has to be strong enough to swing that arm forwards, and weak enough not to wear out the pivot or break off either of the attachment points. Of course, an exact replacement spring steel one would be good (and the least likely to deteriorate and/or give off contaminating particles), and the original has a 10 mm coil length contracted, 17 mm installed, coil portion extends to 21 mm when arm full to the rear, 2 mm outer diameter. Add another 2.5 mm total for the attachment point loops. If you do pop the cover there's another spring similar (but possibly shorter) to it used as the head assembly retractor, just in case you need a visual to go on. Hey, just improvise! You could be the only person in the world transferring data assisted by a spring made from a toy balloon! [] ]'>