I have an N scale Arnold-Rapido S2 that I just purchased on eBay. After 5-10 minutes on the test track the rear truck started to click and jump. It’s obvious that the worm gear is slipping and riding over the gear beneath it, for some reason. Does anyone have any general advice on fixing this? Better yet, is there an N scaler with an Arnold-Rapido S2 out there that knows the disassembly sequence for this thing? The wheels come off easily (they’re not the problem - the symptom is still there) but after that it’s not obvious. And this loco has a lot of very delicate handrails (not sure if they’re original or added detailing) which make me very cautious about applying force. -JB
Are you sure that it is not a cracked axle gear, symptoms are consistent.
Yes. When I remove the axles entirely (which is about all I’ve been able to do so far), it still does it.
-JB
Although obvious to me, it may have slipped through unnoticed…are all rotating axles able to turn? Sometimes grit or gunk acts like a brake on rotating surfaces, and the result is a frozen axle. Since the gears are plastic, and probably journaled in plastic there will be flexibility that lets the gears skip.
Once you have determined that all related rotating objects are indeed free to do it, then you might try shimming one end of the motor to adjust the angle of its driveshaft. Loosen a thread or bolt, and slip thin styrene or even thin cardboard under that end.
Is the worm going into the truck verticaly or is it mounted on the top of the truck going horizontaly? If it’s horizontal then you could try putting thin plastic strips between the worm bearings and the worm retainer.
I assume horizontal, from the way it behaves. But since the disassembly sequence is not obvious (at least to me), I haven’t yet gotten in there to have a look. Thanks for the suggestion.
-JB
The wheel axles were, but I suspect some other axle/gear is jamming. There was a noticable amount of free oil when I took the truck apart. I sopped it up with a Q-tip but it’s clear that somebody over-lubricated things at some point.
Thanks for the suggestion. I’m just going to have to try harder to get the thing apart, I guess.
-JB
Slipping gears do not usually skip, snap, and jump. Sounds a lot more like a cracked gear to me too.