The usual cause is old sticky lube. The needle startes slamming back and forth, eventually hitting the pin hard enough to snap it. With no stop, the the shaft then rotates 360 degrees and wads up the coil spring meant to return the needle to zero. With the shaft now immobile and no lube, the shaft and bushing it rides in, wear out.
Best to disconnect the cable soon as the needle gets jerky.
I'm sure there's someone over there to fix it - I repair them, but bet you wouldn't want to send it all the way here in the US.