I've recently assembled the A1 Acro, w/ Scribe and seem to be having a problem w/ the scribe.

It was working (e.g. pen up / pen down). Now, however, it seems to be pushing the servo non-stop. e.g. running the arm solid.

I've reset the blackbox, and started over, but, still, it persists.

 

I ordered another scribe, to try, and it worked for a while, however, once again, I've problems w/ the servo. Now, it appears that if I remove the spring tension, the servo will raise, and, indeed, will hold the pen lifter high. and, M3 S0.. will indeed lower the pen. However, if I don't remove the spring tension, the servo seems incapable of lifting.

Is this a bad batch of servos?

The rest of the machine, works pretty great.