Mr. Christmas music box bells not sounding

I was hoping for some advice on a Mr. Christmas music box with 6 bells, only 2 of which rang, and that was weakly.

The bell striker has a tiny ball, supported by a flexible wire which terminates into what looks more like a ball point pen spring. You can twist this counterclockwise and pull it out for inspection. I tried to use needle nose pliers to bend them slightly but realized that this will not be effective

By the way, when bells are barely audible, the comb tines drown them out, so, you can lay some masking tape down on the tines of the comb to muffle them to be able to hear faint ringing of the bells as you get them working.

Also, masking tape on the bells that ring clearly will then allow you to hear the differences among the weaker bell sounds as you work.

One other preliminary maneuver is to loosen the bell screw quite a bit. It is hard for me to see if a striker is actually hitting the bell when I hear no sound. Loosening it allows it to jiggle if struck.

I had a feeling that most of the problem has to do with not enough use. So I opened the bottom of the box and could look at the behaviour of each servo motor and bell striker apparatus. All but one actually moved as the disc rotated through a song.

I wiggled each arm and found that the non-functioning one actually had resistance at the beginning of its swing. Further, there were nice DC voltage spikes on my meter when the bell was SUPPOSED to be struck.

So I put a couple of drops of very fine motor oil (Leslie oil) at both ends of the motor shaft, working the arm back and forth and tipping the bo each way, hoping to get the oil at least just inside the shell of the motor.

That made all the difference. So I applied a small amount of oil to the other motor shafts, and gradually the volume of the bell sounds increased. It helped to manually wiggle the arms. I repeated the oiling once.

O have to say that now there is a dramatic sustained improvement, although the problematic striker sometimes needs a little flick of the finger. I suspect that this will resolve with further usage.

I have included a photos of the striker assembly. I found that I could rotate this counterclockwise, loosening it, repositioning and tightening. But I plan to apply a bit of glue where it joins the stem so no energy is lost from any looseness.

Also a photo of the underside of the box, cover removed.

So the advice I seek is whether using fine oil will create problems down the road if it thickens. Should I have tried graphite instead, and how would that be applied in such tight spaces?

Thanks in advance.