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Discussion Starter #1
I have a Bachmann train set 4-8-4 (#806 from the overland Limited set) which runs quite nicely and is in the greyhound scheme, which is what I want to pull my gray UP passenger coaches. I am going to convert this to DCC with sound. The tender already has a provision for an oval speaker, and I have one on the way to fit it. The decoder go in the locomotive, since there is plenty of room for it, and that means less wires running between loco and tender! (Always a good thing!)
Here is the locomotive and tender:

Here i have the shell off, the motor removed, and the light board and smoke unit removed. The cavity where the board was is where I plan to put the decoder.



I have a question about the motor. There are capacitors and resistors attached to it.


Can I simply remove these? I plan to install a resistor in the wire going to the headlight, and the smoke unit will not be reinstalled. I would much prefer to solder the orange and gray decoder wires straight to the motor terminals.
All in all, this looks like it should be a fairly simple install.
I love a challenge!
 

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Yeah just take them off, I thought they made a difference but have not seen any difference in performance with them on or off.
 

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The capacitors maintain a phase difference between the stationary coils. This is usually for starting the motor. The resistors help this action but also are current limiting, to keep from burning up the motor should an over voltage condition occur. I would keep them for their safety factors, and if there is enough room for the DCC board, why remove what is working. Over 30 year as an electronic tech in and out of the Navy I always used the adage if it ain't broken don't fix it.
 

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I'm sure those capacitors aren't for changing the phase, a .1uf cap wouldn't make a dent in the phase. In addition, that's a DC motor, phase simply isn't an issue.

The caps are for spike suppression, the .4 ohm resistors are there for the same reason. It's probably desirable to have them, but it really depends on the DCC encoder, I'm sure most motors don't have them.
 

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In regards to the resistors, what is the possibility that the motor isn't a 12 volt motor?
 

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almost none. It is a Bachmann motor (same type in an SD40-2) and I had to replace mine when I did it's DCC install and the new one did not have those resistors. I contacted them to be safe and they said it was fine. I think it is used more for there shaky decoders they use on their engines. I replaced the original DCC one from them with a DCC&Sound one. Most decoders available today have the things like silent drive, and smooth operation built in.
 

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The capacitors maintain a phase difference between the stationary coils. This is usually for starting the motor. The resistors help this action but also are current limiting, to keep from burning up the motor should an over voltage condition occur. I would keep them for their safety factors, and if there is enough room for the DCC board, why remove what is working. Over 30 year as an electronic tech in and out of the Navy I always used the adage if it ain't broken don't fix it.
DC motors in HO and N have no fixed coils, they only have a coil powered armature.;)

Like Gunrunnerjohn said they are for spike suppression.
The reason for the resistors are to cut out on the back feed to the decoders.
Both are counter productive to a good DCC decoders operation.
John they are not ENcoders they are DEcoders,:D They decode the signal that the command station encodes.;)


I'm sure those capacitors aren't for changing the phase, a .1uf cap wouldn't make a dent in the phase. In addition, that's a DC motor, phase simply isn't an issue.

The caps are for spike suppression, the .4 ohm resistors are there for the same reason. It's probably desirable to have them, but it really depends on the DCC encoder, I'm sure most motors don't have them.
In regards to the resistors, what is the possibility that the motor isn't a 12 volt motor?
In HO, it's very likely for it to be 12V or greater.:cool:
Most HO motors are actually good for up to 18V.:)
 

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when you install the oval speaker i would like to see the pictures my tender don't look like there is enough room without drilling thru the weight
 

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Discussion Starter #15
Okay, the speaker is here. It's not a very big speaker, because, as you mentioned, there isn't a great deal of room for one.
This is the speaker I bought:
http://www.ebay.com/itm/160778463388?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
It is an 8 ohm speaker, and the mounting holes line up perfectly with the holes in the tender's speaker plate.
I used a drill, marked with a piece of tape so as not to drill through the plastic detail piece located under one of the mounting holes on the tenders speaker plate. I drilled both mounting holes on the plate.

The detail piece I am referring to is in the upper right hand corner. This goes towards the rear of the tender.

I used 2 2-56x1/4" screws to secure the speaker to the plate. Here is a pic of the other side of the speaker.

After drilling the holes in the mounting plate, I used a 2-56 tap to thread the holes. Some people don't bother tapping plastic, but I do.
Here is the speaker mounted to the plate.


Here the plate has been inserted into the tender. "Houston, we have a problem." You can see that the speaker extends into the tender past the slot where the two weights slide in.


I think what I will do is cut the weights in thirds and the slide two in the slot, gluing them in place. The remainder will be glued on top of them or glued to the tender in the front half (a combination of both.)
Power for the speaker and rear tender light will be supplied via a 4 pin mini connector plug between loco and tender.
I haven't quite decided how to do the rear light, as this engine didn't come with a function back up light. i may have to some very careful drilling to the casting to be able to get a light back there.
 

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Discussion Starter #17
It's the front. Just use a small screwdriver on the top front of the tender, between the front panel and the top of the shell, and the front will come loose from the shell. It's just a snug press fit. A small jewelers screwdriver is what I used.
 

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Thanks for the help now i can get the sound decoder installed when i decide what 1 i am gona use! BTW what sound decoder did you use im thinking of a tusiumi sound decoder i already have a dh123 in the engine!
 
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