richg1998The loco light picks up from the frame and the wire from the tender. The light is not in series but in parallel with the motor leads.
This is sort of what I assumed. But when I removed the boiler from the loco frame, there was only one wire that connected to the top motor brush. Checking things electrically I could tell that one side of the light was connected to this same lead. But since there was not a second wire from anywhere else on the boiler to the frame, I don't know how the other lead of the light connects to form the electrical return path. This will bear some other looking into.
richg1998You could use some Kapton tape for insulation but would need a nylon screw for attaching.
Yes, I was thinking electrical tape. The nylon screw may be a problem if the mounting screw turns out to be metric as shown on some of the MDC diagrams. Another thing to investigate.
richg1998Too much thickness tape and you will have a sloppy fit between the motor worm and worm gear on the secondary shaft. You will have to shim the rear of the motor a little. This will be a challenge.
Actually, when I was trying to get the thing to run on DC, it would just sit there and do nothing. Then I removed the motor and connected leads directly and the motor ran. Reinstalled motor and nothing. I finally figured out that the worm was engaged too deeply into the worm gear. I ended up shimming the motor with 0.035 inch of Kadee washer on the mounting screw between the frame and the motor. So a little tape thickness might actually be helpful.
Thanks for the info.
Regards
The plastic housing fits into the spot where the open frame motor fits. According to the link you included, look at how the motor fits in your loco. I do know some locos have one brush internally connected to the motor frame. That would requite isolating the frame of the motor.
My MDC boxcab with open frame motor does not have that arraignment. One brush connects to the frame with a wire. The other brush to the left rail pickup with another wire which in your case is from the tender. The loco light picks up from the frame and the wire from the tender. The light is not in series but in parallel with the motor leads. My old MDC are like that.
MDC upgraded the loco motors before being sold to Athearn is what you see in my attached photo and they kept the same basic frame but went to the plastic motor housing and a better motor.
This was probably easier for me to visualize as I have been a mechanical/electrical mechanic for may years. No doubt your mileage may vary.
The motor may not be an issue like someone in the other forum mentions.
You could use some Kapton tape for insulation but would need a nylon screw for attaching. Kapton tape is thin and strong. I get my Kapton tape from Litchfield Station, a DCC supplier. Too much thickness tape and you will have a sloppy fit between the motor worm and worm gear on the secondary shaft. You will have to shim the rear of the motor a little. This will be a challenge.
Others will comment.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
richg1998One motor brush connects to the frame. Remove this connection. Connect the orange and grey wires to the brushes. Red wire to the frame, black wire for the left rail which comes from the tender.
Thanks, but I don't think I have what you are describing. What I have looks something like this: http://www.hoseeker.org/assemblyexplosionMdc/Assembly%20Explosion%2020L-2%202-8-0%20Narrow%20Gauge%20Onside%20Frame.jpg. There is no connection from the lower brush to the locomotive frame. I believe that the brush is electrically connected to the motor frame, and the motor frame connects to the engine frame with one screw to complete the circuit. Also, your posted picture seems to show that the motor is supported in a plastic cradle, which would make isolating the motor frame from the engine frame easy. The model I have does not have this cradle, so unless the motor in the photo is shorter (less tall) than the original to compensate for the cradle thickness, that assembly won't fit.
Also, the head light wire seems to be in series with the wire that comes from the tender (but I haven't unraveled it yet to be sure), so this would require another set of wires to the decoder. But that is a problem to be solved later.
Measure the motor current with a multimeter and 12 volts DC with drivers slipping. If not much higher than 0.5 amp, a SoundTraxx Micro-Tsunami, 0.75 amps, will work just fine. Don't know about the standard Tsunami decoder size. Check the SoundTraxx site for decoder dimensions.
One motor brush connects to the frame. Remove this connection. Connect the orange and grey wires to the brushes. Red wire to the frame, black wire for the left rail which comes from the tender.
I have done this with the older MDC locos using a Micro but in HO scale but I used a new Roundhouse tender frame from Athearn. The old MDC tender frames are mostly weight and not much room. No, Athearn does not make this loco any more.
You also might try replacing the motor with the newer open frame motor with skewed armature that is now in the Roundhouse locos. They run very nice and a little under 0.5 amps.
At the HO Seeker site you can see the insides of the newer loco diagrams at the HO Seeker site. The motors are available for $5.00 for a pair from River City Railroad at ebay. The gear drives look the same as Hon3 and HO. You can add a flywheel also as the motors have double shafts.
Below is a photo of what the drives look like. Might work for the HOn3. At least I would try it as I would like the challenge. The 4-4-0, 2-6-0, 2-8-0 have identical arraignment. I suspect the Hon3 was just a little narrower.
Our Club has an MDC HOn3 outside frame 2-8-0 that we would like to potentially add a sound and motor decoder. This model appears to be an earlier version than what I can view on the HOSeeker site.
Has anyone put a sound/motor decoder into one of these, and if so, could you tell me what decoder was used? If there is a link to somewhere that would show the installation (I presume that it would be in the tender), that would be appreciated.
Also, I took the boiler off the frame to see how the motor is mounted. The motor is a Japanese open frame with the brushes mounted at noon and 6. The upper brush seems to be insulated from the motor frame, but the lower brush is grounded to the motor frame which is then further grounded to the locomotive frame through the motor attachment screw. Obviously the motor needs to be isolated from the frame. I'm curious as to what motor mounting method would be recommended, as I'm not necessarily willing to rely on a "goop" attachment instead of something that would allow motor removal if required.
Any thoughts on this?
Thanks
(PS: I am posting another question on regearing this engine in the general forum to avoid cluttering up this post too much.)