Kato NW-2 wiring mod help (mod completed

[scubaterry]

When I bought my Kato NW-2 I had the HS tech install the decoder for me due to at that time my lack of experience. Today I began a project of painting various Loco's to NYC colors. Upon taking the NW-2 apart I realized the wiring is differant than I have seen on other loco's. Apparently both halves of the metal weight are isolated and a brass strip rests on each side contacting both trucks by friction alone. That may explain why after a year the loco would not run as reliably as it did when new. SO with that said I am pondering on whether to get rid of the brass strips and solder fine wires to the small brass tip on the trucks. Problem is there is not much surface on the small tab on the trucks. I think if I could figure out how to take the truck apart I could do it. Anyone out there "been there done that" or have any comments before I tackle it?
Terry[8D]

[scubaterry]

Anyone have any experience with this?
Terry[8D]

[jeffers_mz]

I have the loco, but no decoder and no problems, it runs smooth as silk. From soldering track, I can say i'd much rather solder nickle steel than brass, the oxidation doesn't seem to have an affinity for solder, makes it want to bead up. If you can get to it to clean it well that may not be a problem. If there was an alternative way to wire necessary leads, even involving drilling the weight, I'd consider it, the loco has pulling power enough to spare a few grams.

[cacole]

What scale and year of manufacture is your engine? I have put decoders into 4 Kato NW-2 HO-scale models a few years ago, and none of mine were wired anywhere near what you are trying to describe.

On the HO scale versions, the frame halves need to be separated to get to the motor brush contact wipers that press against each side for electrical pickup. The decoder's output wires are soldered to these contact strips, which then MUST BE insulated from ever touching the frame again.

[SMassey]

OK this could be caused by a few different things.

I do have this loco and I have converted one to DCC and it runs just fine. But I did notice when I made my conversion that there was a few different spots that could be a problem. On my loco I put an "N" scale decoder in the fuel tank area (Had to grind away some metal) This could be a problem due to smaller electronics but an HO decoder would not fit anywhere but in the cab (did not want to have the decoder visable or the windows painted black). The "N" decoder was rated for my NW-2's amp draw and so far so good for me.

By putting the decoder inside the tank I needed to run wires up the frame to the top for the lights. These wires run really close to the motor and may eventually need to be reinsulated due to the sheething being worn off. Again so far my wires are not touching the motor so there is no problem there.

The origional design of this loco puts power to the actual frame of the loco. This is fine for DCC but you have to isolate the motor and the lights. I cut the PC boards to isolate the lights and as for the motor I just used black electrical tape to isolate where it could touch the frame and let the trucks energize the frame like it did in DC. I soldered the decoders pickup wires right to the copper strips that span between the trucks, there is not enough room to run and merge wires from the front and rear truck the strip works just fine.

Make sure that strip is clean and put a little electrically conductive grease on the contact points to make sure you have a good connection. You can find this grease at most auto part stores in the towing section.

I dont need to tell you to make sure the track and wheels are clean that as we know is a given for our railroads.

Check that all wires are in good shape and that your frame halves are still insulated from one and another. Even if the halves are still insulated you may need to take the loco apart and check the motor area in case a little grease from the motor and the dust from the brushes has not build up in that area causing a small intermittent short in the loco's frame.

Also make sure that the decoder is not fried. I have one that only works when it wants to and that is not that often so I just removed the decoder and retired it from service.

I hope this helps you get your loco up and running again.

[scubaterry]

cacole - It all ready has a decoder in it. I bought it at my LHS about three or so years ago and its HO scale. Actually there is nothing wrong with it. I just noticed that I could improve on the electrical pickup for the trucks. I have no intention of removing the two halves. that would be a headache. I did get adventurous and took the side frame off one truck and removed the brass flat that connects the two wheels and makes contact with the brass strip. The right side will be easy as there are two screws holding the two halves together with a plastic nut on the other side to isolate the two halves. I can solder a wire from one truck to the other and connect the red wire from the decoder and the truck wire to one of the screws. The left side will be more of a challenge as there are no existing screws. I found a small place below the cab that I can drill a small hole for a screw head and tap it for attaching the left side, I think If I clean the brass good and use a quality rosin core flux I can get a wire soldered to it. If I am all hosed up on my theory someone let me know. But after looking at it dissasembled it appears to be cut and dried. I have noticed (with no maintenance) over the last year or so it does not run nearly as smoothly as before. I could probably fix the problem by cleaning up the brass strip and brass truck contacts. It just seems to make sense to hard wire the whole thing while I have it apar insteadt.
Terry[8D]

[SMassey]

The material that the frames are made of do not solder at all. The frames are made from an aluminum alloy that is not of very good quality but has more weight than other grades of aluminum. check what I have said above you may inprove performance with a little cleaning. It also sounds like you may need to have the motor cleaned as well. If you run this loco at low speeds and have a load on the motor alot (like most of us do to our switchers) you may also have a high level of carbon buildup on the armeture of the motor. Most LHS's that handle R/C cars can provide you with a bru***o clean the carbon off the copper plates of the motor. Remember if you use any type of electric contact cleaner that you will have to reoil the bushings at either end of the motor. I dont recomend using a pencil eraser for this the shavings will get into everything in the motor and cause problems later on down the road. Due to the limited amount of space inside this loco I dont think removing those brass strips are a good idea. clean them and put some contact grease on them you should be fine. I have one converted to DCC and one that is still DC and they are both running just fine after almost a year of service with the contact strips just as the factory had them.

[scubaterry]

OK Mike you talked me out of it. I wasn't actually going to solder to the body. I was going to solder a small wire to the truck brass tabs and solder that wire to the decoder wire. Thats the way my P2K locos are wired. I figured a hard wire job had to be better than a brass friction contact. I have some Conducta lube will that work by putting a small bit on the brass strip where it contacts the truck brass point to improve conductivity? How much work is it to take the two body halves apart? I know its only two screws holding it together but how hard is it to put back together? Tks for the info.
Terry[8D]

[scubaterry]

Mike I just realized I had missed your first post. I just read it and yes I also have an N scale decoder (in the cab). I also had the wires soldered to the brass strips from the decoder. Acutally I think maybe I was not very clear on my first post. There is nothing wrong with the loco it runs fine just not as fine as it did several years ago when I bought it. I have six loco's that are from other RR and I decided to paint the bodies on a couple of them today so I can decal them for the NYC. That is when I discovered the brass strips on the loco. I was just thinking that It could be done better by soldering the trucks together and then up to the decoder leads. Maybe I could solder the truck tab to the brass strip that is connecting to it giving it a friction point and a hard soldered point? Maybe I am inventing a solution when there is no problem.
Terry[8D]

[SMassey]

Taking the halves of the loco apart is not that hard. After the body comes off there is a small printed circuit board in the front that needs to be pulled out. Remove the 2 screws that to through the frame sides (dont lose the plastic nuts on the back side) then open the frames up. The trucks will then come free and you should see the motor assembly and gearing. There are little bushings on the ends of the worm gears and also one side of the frame has 2 little brass springs behind the worm gears. Make sure to be careful not to lose any of those parts. The motor is a typical Kato motor that you can see the open end bell and see if your armeture is carboned up. If so get a "Comm Brush" (short for Commutor Brush) and turn the motor while pushing this brush against the comm. (the comm or commutor is the part of the armeture that the brushes contact usually made of copper or brass).

Yes I think you are trying to find a solution where no problem exists [8D] just a little TLc and cleaning is all I think you need from what you have said.

PS make sure to put what ever the HS put in the frames to isolate the motor from the frames if not you will fry the decoder.

[scubaterry]

Mike how about conducta lube? Doesn't that clean comm brushes?
Terry[8D]

[SMassey]

No that will mess them up and cause a really nice hard to remove gum coating on the comm. If you put any type of lubricant on the comm and brushed you will only cause yourself more trouble. The best way to have your brush/comm contact surface is dry and clean. A little carbon scoring will be normal. Plus you want the "dust" to fall off the motor so it will not short the plates together if you put any type or grease or oil on the comm surface the "dust" will stay possibly shorting the comm. That is bad! [:P]

[dacort]

I have a Kato NW-2 that I wired much as you described. I removed the contact strips that fit on the frame above the fuel tank and substituted wires that are soldered to the metal parts of the truck frames on both sides. One truck is wired to the decoder, and both trucks are wired to each other.

I also went a step further and added some additional brass contact wipers made of thin brass rod that rub on the wheels for more positive contact. Since then I've had far fewer problems with the engine stalling.

[bogp40]

QUOTE: Originally posted by dacort

I have a Kato NW-2 that I wired much as you described. I removed the contact strips that fit on the frame above the fuel tank and substituted wires that are soldered to the metal parts of the truck frames on both sides. One truck is wired to the decoder, and both trucks are wired to each other.

I also went a step further and added some additional brass contact wipers made of thin brass rod that rub on the wheels for more positive contact. Since then I've had far fewer problems with the engine stalling.

Great idea, I have been having problems w/ those nasty bronze wipers lately. Just wasn't looking forward to pulling it apart just yet. But that's the solution. Thanks
Bob K.

[scubaterry]

Dan thats exactly what I was trying to explain (very poorly). So you have both trucks on a side wired together and then up to the appropriate decoder wire. That is the simplist way to do it. I was trying to make it hard by wanting to use the metal body as a grounding point when in fact that contact is eliminated when you get rid of the brass strip. How did you make room for the wires running the length of the body? I know it is a tight fit. I guess with the brass strip gone you could lay the wire along the same path?? That's why I love this site everyone has a different perspective. Can you elaborate more on the additional brass wipers? Thanks to everyone for your input.
Terry [8D]

[rolleiman]

QUOTE: Originally posted by scubaterry

When I bought my Kato NW-2 I had the HS tech install the decoder for me due to at that time my lack of experience. Today I began a project of painting various Loco's to NYC colors. Upon taking the NW-2 apart I realized the wiring is differant than I have seen on other loco's. Apparently both halves of the metal weight are isolated and a brass strip rests on each side contacting both trucks by friction alone. That may explain why after a year the loco would not run as reliably as it did when new. SO with that said I am pondering on whether to get rid of the brass strips and solder fine wires to the small brass tip on the trucks. Problem is there is not much surface on the small tab on the trucks. I think if I could figure out how to take the truck apart I could do it. Anyone out there "been there done that" or have any comments before I tackle it?
Terry[8D]

Terry, I haven't read through all of the other responses in detail so forgive if this is all repeat. It Sounds like your installer isolated the motor from the frame and used the frame as track pickup just as originally shipped. That's all fine and well until the pickup begins to wear out (or it gets dirty).

I've been in progress of converting my Own NW-2 to DCC.. You should notice that there are tabs coming out from behind each truck sideframe that rub on those bronze strips on the frame. What you want to do is A, Remove those strips, and B, Cut the tabs off of the trucks and solder wires to the remaining part.. You kind of have to see it to understand what I'm talking about.. To do it, you'll have to pull the side frames off to free the bronze bearing strips that hold the axles. Once you have them loose, simply clean off a spot, tin it with solder and then attach a wire. Depending on where the decoder is mounted (top or in the fuel tank area) you'll have to route those truck wires To the decoder. On mine, I milled slots in the sides of the frame halves to route the wires. The decoder itself (Lenz 077, iirc), is mounted in a creavice milled out in the nose of the frame under the headlight. You have to make sure though that nothing sticks out.. The frame is a Very tight fit in the body as you probably noticed in getting the thing apart. If you need to see it, let me know and I'll snap a few pictures.

Good luck.

[scubaterry]

Jeff why remove the tab on the truck? I figured I would just remove the brass strip altogether and solder a wire to the truck tab. Connecting both trucks on each side together and then to the red/blk decoder wires. Tks for your input.
Terry [8D]

[rolleiman]

QUOTE: Originally posted by scubaterry

Jeff why remove the tab on the truck? I figured I would just remove the brass strip altogether and solder a wire to the truck tab. Connecting both trucks on each side together and then to the red/blk decoder wires. Tks for your input.
Terry [8D]

On mine, I'm actually using the frame halves to conduct power to the cab for the rear light since there's no easy way to route wires in there. I didn't want track power interfearing in any way with the lighting circuit. If the tabs are left in place, I feared that they would bump the frame and short the decoder. This is still a work in progress but since I've already milled away about 5-10 percent of the body weight, I'm past the point of no return. I've probably made the whole thing a lot more difficult than it needed to be but I'm kind of screwy that way [}:)]. Anyway, Cutting the tabs just insures that track pickup remains only as track pickup.

[SMassey]

Hmmm I never thought of putting the decoder in the nose under the light. There is alot of extra metal there that could be milled away pretty easily. I may try that with my NW-2 that is still DC.

Thanks

[scubaterry]

Jeff - Tks for the info sounds like a prudent thing to do taking the tabs off. In my case the rear light wires are running down the crack between the two halves. They fit nicely and are out of the way. So I don't have to worry about the trucks touching the frame. I was planning on filing just a bit of body just above the tab anyway just to make sure the tab didn't interfere with the body on turns. I know what you mean by being too far into it to stop now. That sounds like most of my projects. This has been a great thread I have learned allot. I feel confident that I can now go in and make this a better model.
Next I am going to tackle my two Kato RS-2's. It has a similar setup with brass strips. I read a thread several years ago on how to hard wire them so they are more reliable. Of course I can't remember squat about the thread but it has been done.
I really like the Kato loco's. I just wi***hey would come out with some of the older models something in the 1940 -1960 range.
Terry [8D]

[scubaterry]

Well I completed the truck wiring mod today. I drilled small holes in the tip of each brass tab on the trucks and soldered fine flexible wire. Connected each truck on a side and then to the appropriate decoder wire. Put it on the track and it worked fine, however it has low end problems. I have to crank the DT-400 up to 18 before it begins to move. Once it moves at that point it seems totally normal. I can feel and hear vibrations as low as 5 on the throttle but it does not move until 18. I thought maby my new wire was rubbing a wheel or something but could find no probem there. I then set the Vstart and acc CV's to 0, cleaned the track and loco wheels to eliminate sources of problems. So I guess next step will be to get the Comm brush and clean the commutators and see if that will do it. The problem is I can't remember exactly how it ran before all this. It has stayed in the box most of its life. Any ideas on anything else I should check.
I also painted and decaled (for NYC) my 1984 Ath BB F7A. It looks really sharp. OF course the decals could be a little straighter.
Terry[8D]

[dacort]

My NW-2 developed a problem where one truck would stop moving while the other kept spinning, making it run very badly. I pulled my hair out for a long time on this one, as it was intermittent and very hard to track down. Eventually I figured out that one of the universals on the motor was spinning on the motor shaft. A little glue fixed that and ever since it's run great.

[scubaterry]

Dan thanks for the info I will check it out however I doubt that is it because once it gets moving it runs fine. It acc and decc correctly. It just needs a bunch of juice to get rolling. I think something must be rubbing or as someone said yesterday the motor commutator might need cleaning??
Terry[8D]