singer 29k71 troubles

[b2k]

After replacing a broken nail, the machine started skipping nearly all stitches.

On a closer examination I found this:

I think that is a broken thread retaining spring, at least judging from the parts manual it seems to miss the paddle head.
If that is the case I suppose to have found the culprit.
In this case, how difficult is to replace this part? Do I have to unmount the whole needle bar?

And, if this is not the problem, what could be the cause of the missing stitches?

[Trox]

Sure you have pushed the new needle all the way up- and the needle was brand new? Ask CowboyBob (Toledo industrial Sewing machine), he has a lot of Singer parts and know these machines. Are you sure that part broke just now.

Tor

[Wizcrafts]

It sure looks like a broken off paddle spring to me. That means there is nothing holding the thread loop in place. It must be replaced.

Once the new spring and screws are ordered, begin dismantling the needle bar at the top. Everything in its way must be removed  to allow it to come out the top. Also remove the needle mounting clamp!

There are two tiny screws holding the paddle shaped check spring in place. In most cases, at least one will have been filed down on one edge to clear the barrel it rides in. If you reuse these screws, make sure you replace them into the same holes. If you install new screws, if you feel tightness when turning or lifting the needle bar, you may need to file the side or sides of the screws to clear the barrel.