I’m hoping you all can help me with a motor issue. A while ago, I purchased a blue box Proto 2000 SD9 from eBay. I have now just gotten around to adding a DCC sound decoder. I put in a TCS WOW Sound WDK-ATL-3 kit, which fits in the loco beautifully. Unfortunately, all of the internal wiring was black, so I tried to the best of my knowledge to add correct color wiring re: NMRA. When I finished the install and put the loco on my programming track, the sound on the loco started up immediately, the new led front and rear lights work great, but the motor does not run. Well, it does TRY to run. It makes a buzzing noise and I see the armiture trying to move, then it stops trying to turn and the buzzing continues.
Would the issue with the motor possible be caused by a mixup in the positive and negative motor wires, the right and left truck wires, both, or none of the above? I see the motor start to turn, then stop.
Does the motor buzz all of the time it is on a powered DCC track or just when you apply the throttle? if it Buzzes all the time you might have a track power wire/ wires connected to the motor, usually that causes other issues to though, and you said the sound and functions were working like they should. If it only buzzes when you throttle up then it sounds like the motor is binding somehow. Did you test run it on DC before the decoder installation? Those blue box proto SD9s are getting pretty old, I’m wondering if the grease in the trucks solidified a bit or somthing else in the drive line is off. Hope you can get it figured out, I have one without sound, they’re really nice running loco’s when they work properly.
Did it run OK in DC? Always a good idea to check first and check the current draw, too as Jamie mentions. As long as the motor is trying to turn the decoder wiring is probably OK. Won’t matter if motor + or - are switched.
Try “rolling” each wheel with the locomotive upside down in your hand. If any of the wheels can be spun with pressure from your thumb you have a cracked gear.
So, I suspect there may be the cracked gear syndrome at play here? You can carefully pry the bottom cover off the trucks and check both the gear condition and grease.
I clean the grease out and replace it with the LaBelle PTFE stuff just as a routine precaution.
Extreme cases of cracked gears can jam the mechanism - not terribly likely, but it could be. If you turn the armature by hand, does it spin all the way around? If so - I’d say electricla issue, a buzz sounds like a direct connection between the track pickups and the motor, as menthioned. If it DOESN’T turn, then you’re looking at a mechanical issue and the bozz is just the motor TRYING to spin.
Well the good news is it sounds like you got the decoder wiring all right. If it’s possible to remove the trucks from the locomotive you would be able spin each of the trucks gearing individually and get an idea where the binding is happening. If you open up the gearboxes to clean the old grease be on the lookout for foreign objects to. I once had a Kato SD70mac bind up after getting a single grain of ballast into a gearbox on one of its trucks. I was amazed that something so tiny could do that…
Thanks for all the suggestions! I decided to take everything apart and it turns out the rear cardan shaft was frozen. And of course, when I tried to work it loose, the shaft broke! So, now I need a new worm gear package. Does anyone know where I can get a replacement?
Shop around, sometimes these kits can be found on ebay or some of the discound hobby suppliers. It has been a while since I’ve had my Proto SD7/9s apart so I don’t recall exactly what style of drive shaft is in there.
It is identified in the parts list as 584739 SD9 Worm Gear Package w/worm retainer clip. (Contains: Bearings, washers, worms, joint bushings and cardan shaft)
I looked at the site and cant really tell what kind of drive I have…hex or not hex. The worm couplings on the hex drive look the same but I don’t think the flywheel is a hex. It has the same t type end as the worm gear side. Any thoughts?
Is the drive shaft one piece with the T or dog bone shape on both ends? It can have a hex drive on the fly wheel side and the T shape on the worm gear side.
If it has the T shape on both ends, there would be a slot on the fly wheel side that the shaft fits into, just like the worm gear end.
I don’t have a P2K SD7/9 to look at, but I do have some GP’s. Ill go see what I have on mine.
I checked mine, and all of the P2K’s I have, have the “knuckle” (like a drive shaft) end, so mine are the spline shafts.
If they don’t have a replacement shaft for the T on both ends, maybe the flywheel connection comes out and can be replaced with the hex. The hex part is only on the flywheel end.
Same thing. Gerolamo Cardano is the guy who invented the things somewhere in the 1500’s. Most people these days just call it a drive shaft, but some places still refer to it as a Cardan shaft.
Don’t know if the flywheel connection is removeable, but I will give it a look. Haven’t heard back from Walthers on a possible replacement yet. I may have to look into trying to change the whole thing over to a hex system if possible.
was a mechanic for years and the two are not the same to me what i call a carden shaft is from diff to hub with a double u joint at one end , or a carden joint.