I asked this question within an older thread, so it probably got overlooked. Wondering about the DCC board in the Bachmann 44 tonner, there are a couple of "Chokes?" and a "capacitor?", I recall something about being able to remove these and improve the running. The biggest problem I see with these great little engines is the pick-ups. The tabs on the trucks have no springiness and lose touch with the under chassis contact area, has anyone successfully hard wired through from the trucks to the chassis? Ted (Teditor) Freeman From The Land Down Under.
The whole DCC board can be removed. I did this and replaced the area on top of the chassis with RC air plane lead weights. The only thing I remember is the wires are not wired tot he board intuitively you have to cross them from one side to the other to get the NMRA wiring standard. As for the contact tabs I have not done that yet but it would be like doing it for the LL SW and bypassing those stupid shell mounted wiper strips. Mike
I bet you could solder micro-trains coupler springs to the trucks' tabs, where they touch the underside of the chassis (maybe with another bit of brass soldered atop the spring) and it would help conductivity. Bendy wipers are the worst!
Sounds like an interesting way to overcome the problem, a bit masochistic maybe, I will see how I go and report back. The DCC board modifications (if feasible) are the other problem that needs an answer.
OK, I have done the pickups successfully, the original pickups have little raised dimples, I trimmed the M/T's coupler springs to about 2 thirds their length after soldering them in place, otherwise there was excessive tension pushing the springs sideways. I will be giving the loco a test run tomorrow night at the club, I have a test track at home, but left my handpiece at the club. If any answers to the rest of my question come up, I will do whats needed before testing, otherwise I will consider I misread somewhere and leave the chokes and capacitor as is.
I pulled out my board and just attached the wires to the 2 screws that were used to hold down the board. Guess technically mine is now wired backwards, but that doesn't matter to me. You can cross the wires if you like. Also the capacitor in my photo is not needed and I no longer have it.
Sorry if I have created any confusion, I wish to retain the Bachmann Decoder, just wondered about removal of the aforementioned items. I went on the Ask the Bachmann site and found a reference, according to them, the items in question are a legal requirement in some areas, so instead of picking and choosing, they equip all the locos as such. They are as I suspected, related to noise interference, the degree of which I am about to find out.
Easy as pie! If only their steam tenders were this easy Haha.... Feel free to drop me a PM if you're not gonna use that board, trade for a MTL boxcar or something?
Tried tho loco tonight at the club, found the pickups on the back of the wheels needed a bit of tuning to maintain contact, the Micro-Trains coupler springs worked a treat, though with them at full length, they either push the truck back out or tend to flex out the side, only about one third to a half of the spring is needed to maintain good contact. The removal of the chokes and the capacitor had no ill effects, I will place some lead in the cab area previously taken up by the capacitor, any extra weight in these little fella's should be a bonus. Thanks to everyone for the input.
Been having similar issues with the contact strips. Can you post a photo of what you did with the springs? (Sounds better than soldering wires from the trucks to the frames!)
I would put the capacitor back. As someone said, the chokes are simply to reduce noise- radio interference. But I'm pretty certain the purpose of the capcitor is to absorb pulses when running the loco with an analog DC throttle. In DCC decoders, the loco does not need pulses from the throttle since the decoder makes them. You could run a DCC loco (like this one) on pure DC and it would run fine. In fact, some pulse analog throttles confuse the decoder. You'll also notice 4 black diodes next to the yellow capacitor. Well 4 diodes arranged a certain way make a bridge rectifier. The capacitor is there to smooth out any bumps in the resulting half waves. This is designed to feed pure DC to the electrical components that follow. To those familiar with electronics projects, this is a totaly standard power supply for components. I'd put it back. (in the orientation it came out- there is a plus side and a minus side.)
I haven't got the best camera in the world, I haven't posted photos before, but then, come to think of it, I haven't worked on a Bachmann 44 tonner before, I'll see what I can do.
I don't run the loco on DC, tests last night at the club showed no ill effects and there were other locos running at the same time (NCE DCC). We ran another non converted 44 tonner with this modified one and performance speed wise didn't seem to make much of a difference, however, the ability to start moving was much enhanced with the pick-up mods, I will keep the capacitor in my spares box (boxes)(I seldom throw anything away), time will tell I guess!
The Choke or "inductor" and "Cap" work together to absorb any sort of Sinusoidal wave in the electrical signal as a electronic filter.(First year electronics from ten years ago coming back to me). The Cap will work in line with current flow as it will charge until full and then begin discharging when there is a voltage difference across it. So it will be continuously charge and discharge as the voltage is "used" by the motor to produce mechanical work. The Chokes are normally parallel to the motor and will absorb the other side of the Sinusoidal wave than the cap would. On straight DC they are not required in North America however they are legally required in the EU so Bman includes them in all their DCC boards. As I said I ripped my Board out and added lead above the frame (about 3/16ths worth) as well as crossed the wires so it dose not run backwards as chris333s would in his pic.
I think I may have succeeded, the photos are not great, but hopefully show enough. The tab on the truck is tinned with solder, a modified toothpick is used to hold the N scale Micro-Trains coupler spring, apply flux to the tinned tab and spring, hold in place with the toothpick and touch with the soldering iron (the toothpick stops the solder from wicking all the way up). Cut the spring about half to two thirds (I use Xuron 9180 Photo-etch Scissors), the truck should go back in the chassis with a slight compression noticeable once installed, if you leave the full length spring, it will either push the truck back out, mesh with the worm incorrectly or squeeze out the side (the amount of tension needed is a bit of trial and error). The running quality (pick-up wise) is vastly improved. Removal of the chokes and capacitor have not detracted the performance, I placed lead weight in the cab area where the capacitor previously sat, this was only 3 grams, but as the loco only weighs 35 grams any way, it is almost a 10% increase. We tested the loco by hauling a six car Kato Bi-level commuter set around the club layout, the photo shows the train climbing a 3% grade without effort.
Has anyone else had a go at these modifications yet, I have another 44 tonner as well as a 70 tonner I think could benefit from the same treatment. I realize that the Bachmann decoder is not the best, but it works OK, just has limited functions, in these tiny locos, I don't think that's real relevant, slow speed start may improve with a better decoder, but at this stage I am happy with how it is going.
Thanks for the photos! At some point I'll try to improve the contact points in this way: I've got about 3-4 spare 44-T trucks I've ordered from Bmann, all with wonky contact strips that could benefit from a mod like this. As for the decoder: some people have replaced the stock with a DZ125 or other. I think the stock decoder works alright (for this loco: for Bmanns steamers I've replaced them with DZ125s), and slow-speed improves especially if you reset the CV speed value to "0" (it comes programmed at "10" or something large like that). Impressive that you got it to haul all those bi-levels up a grade like that: most pull 6-8 boxcars max on flat.
A bit of an update, I have just completed modifying another 44 tonner and also a 70 tonner. No changes have been made to the 70tonners PCB fittings, but I did do the spring thing on the truck/chassis pick-up points. This time though, I used the Mico-Trains Truck Restraining Springs, these have a more open coil and didn't require trimming, the 70 tonner didn't seem to suffer quite as much with the pickups, but I went with the modification anyway, "Jus cause I could". Ted (Teditor) Freeman From the Land Down Under.
