RP Install help

[WyldBill]

I'm embarking on my first RP install in an older Bachmann 2-6-2 loco. After I opened up the shell I found this....

I expected to see a can motor and some wires. I'm not so sure what to do with this. Any suggestions on how (or if) I can connect this to an LM-3S module?
Thanks,
WyldBill

[nodcc4me]

I can't see the picture too well, so I can't tell what that is, but is there room in the tender, and wires going to it from the locomotive? I have always installed LMs in the tender and have installed several Spectrum locos. If the engine has a headlight there should be 4 wires, and it should be easy to figure which ones go to the light or the pickups. Yours does not look like a Spectrum, and may be different.

[WyldBill]

Hi Al,
The loco is a Bachmann, it does not have any wires running from the headlight. It does have 3/4" long stiff wires that come out of the bulb and sit against the metal frame. There is plenty of space in the tender to install the LM....but there are no wires at all coming from the white plastic casing which is the motor. Maybe this photo will help

Thanks,
WyldBill

[nodcc4me]

Bill, I have not seen that setup in a steamer, but there must be at least two wires coming from the wheels to the motor. It sounds like the tender is out of the equation as far as pickups go. If you have room in the locomotive for the LM, you will have to find the two track pickup wires, cut them midway between the wheels and the motor, and connect them to the red and black wires on the LM harness. Then connect the orange and black harness wires to the loose ends of the motor wires.

The white and blue harness wires connect to those long, stiff wires that go to the bulb.

I doubt there will be room for a speaker in the loco, but if you want sound, you can mount the speaker in the tender and run the brown harness wires to it.

If there is not enough room for the module in the loco, you could put it in the tender, but you would have all the wires running between the loco and tender, which might not look too good and may cause the tender to derail frequently.

If you are able to pull it off, please post some pics. 

[G8B4Life]

It looks like this is the one: https://hoseeker.org/assemblyexplosionbachmann/bachmann262prairiediagram1990.jpg.

It appears to be an old split frame design, that is each side of the frame carries the track power to the motor; the light being connected to each side of the frame pretty much confirms that. Not an impossible install but a difficult one. The biggest thing is you need to find the electrical path from the frame to the motor brush housings and isolate that path so you can connect the LM to the motor.

Going by what I can see in the diagram, the track pick ups have a spring tab on them which will press against the frame to pass the power. If you soldered the LM pickup wires to the tabs and then insulated the join with heat shrink tube the frame will then become insulated from the track power. You could then solder the LM motor wires directly to each motor brush housing (the two brass rivet looking things either side of the motor shaft). Your pics aren't big and clear enough to see what's happening in that area for me to say for certain what you could do though. You would need to isolate the headlight and smoke unit from the frame too.

Now where to put the LM. The tender is an obvious choice but as Al mentioned you'd have 6 wires running from the tender to the loco.You could possibly fit a pickup kit to the tender if one exists and do your track pickup there instead. Another option is if there isn't enough room on top the frame to fit an LM between the frame and the shell you could file/grind a spot out of the frame for it if you have enough length and width available.

- Tim

[WyldBill]

Hi Tim,
I found that exact same diagram late last night. So that is an old pancake motor in there. What you said make sense....if I were to use track power. But I'm planning on installing a battery in the tender along with the LM so that cuts down on the number of wires to the loco. My only question now is where the motor wires get soldered in.
Maybe this photo is clearer....

I'm not sure what the round items are in the middle of the white plastic housing....possibly brushes like you mentioned. Would I solder wires from the LM to the metal tabs in front of those round holes?
Thanks,
WyldBill

[G8B4Life]

Yep, that's an old pancake motor all right. Should be fine to use with RP though. The good thing about pancakes is generally that can be taken apart to clean the commutator.

Unfortunately your pictures are just coming out too small to see any detail (and of course the diagram is of the wrong side of the loco!) but having seen and dealt with lots of pancakes in my time I can say this based on what I can see in the pic.

The two brass coloured "round items" will be the brush holders. If you took the tabs away you would find (normally) a coil spring and the carbon brush inside (makes for easy carbon brush replacement!). The tabs are where you would solder the LM motor leads (or possibly you could solder the LM motor leads to a pair of small solder eyelets and then just sandwich the eyelets between the frame and tab with the screw that secures down the tabs, but it's too hard to see if that's viable from the pic).

Going battery power will make the install more complicated with all the extra stuff to do but probably make the install easier from a loco wiring perspective. Don't forget though by soldering the LM motor wires to the tabs the frame also has motor power so you would still need to isolate the track pickups from the frame, and also the headlights and smoke unit from the frame as well.

- Tim

[WyldBill]

Tim,
I was planning on taking the loco apart to look at it more thoroughly. Good to hear that a pancake motor will work fine with RP! My plan was to connect the motor wires to the metal tabs going into the brush holders. Does it matter which is positive and which is negative?

I have a lot of experience with RC vehicles so going with battery power is something I'm familiar with. The amount of space in the tender should allow all components to fit nicely, as long as I can get the correct battery size. (They are a little hard to find right now)

Thanks,
WyldBill

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