Black Sheep's back!
I read the 'Model railroader's guide to DCC' and in the book I figured out how to convert the 'OLD SCHOOL' Athearn units, but I have a few Bachmann Spectrum engines that I am wanting to convert to DCC and the book does not even mention how to do that, or even if it can be done to those engines.
Is it possible to convert an open spoke BACHMANN SPECTRUM engine to DCC, and if you can, how would you do it,
Thank, Black Sheep 25
You can install DCC in any DC locomotive. Although the particulars for a Bachmann are different from an Athearn, the underlying principles are always the same in every case. The generic how-to steps below will apply to ANY loco, but you'll have to figure out how to perform them on your particular engine.
1. First, test the stall current on your motor. Read http://www.tonystrainexchange.com/download/DCC-for-Beginners-tte8x11.pdf, page 8 in the middle for a description on how to do this. The stall current will tell you the theoretical maximum current that your motor would ever draw, in a worst-case scenario, so you can choose a decoder with an appropriate current rating and reduce the risk of burning it out.
2. Electrically isolate the motor from the frame. In DC, there are two electrical connections that run the motor - one that is connected to the right side rail, and one that is connected to the left side rail. (At this point, disconnect any wires that go to lights, etc. from the motor.) Bachmann used to (still does?) use a "split frame" electrical pickup to feed the motor. The loco frame itself was split in half, with each half insulated from the other down the center. The current traveled from the metal wheels, through the frame itself, and to the motor electrical leads by physical connection to the frame halves. In other cases, there may be wires running from the frame or wheel wipers directly to the electrical leads on the motor. For DCC, the only electrical connection the motor must make are two wires going to the decoder. The electricity from the rails must NOT reach the motor directly - it has to go through the decoder first. That means you have to electrically insulate the motor from the frame to ensure there is no unintentional electrical connection between them. This is usually done with electrical tape or similar material. Depending on how tight a fit it is inside your loco, this may prove challenging, but not impossible.
3. Connect the two decoder motor wires to the two electrical leads from the motor. (Follow the decoder's wiring diagram to make sure this is done correctly). Connect the two electrical power wires from the decoder to the appropriate power pickup connection from each rail (again, refer to decoder's instructions). For a split frame design, each wire can go to the appropriate half of the frame. Connect each wire by soldering or by drilling/tapping a small screw in an convenient place on the frame. (For more reliability, connect wires directly to whatever is picking up power from the wheels - wipers, metal truck frames, etc. The fewer "mechanical" connections between the rail head and the decoder, the better)
4. Connect light wires to the appropriate decoder wires. As always, follow the decoder's instructions to do this correctly.
Dan Stokes
My other car is a tunnel motor
stokesda wrote: 4. Connect light wires to the appropriate decoder wires. As always, follow the decoder's instructions to do this correctly.
Black Sheep 25, this is all spot on advice given above. Here is some info specifically for the Bachmann Spectrum
1. I have not had a Spectrum with a stall current above 1 amp and a bit.
2. TERMINOLOGY: I assume by open spoke you are referring to a steam locomotive. Or did you mean open frame motor....which I don't believe are in any Bachmann Spectrums. I think I have only seen can motors in them. However older ones are not isolated from the frame so you will have to take the steps mentioned in the posts above.
3. THE GOOD NEWS: When all the steps are written down, the process can seem intimidating to read. Be heartened. After a few conversions, I find a diesel with a split frame can be hardwired as described above in less than an hour. A steam locomotive with an NMRA plug would be faster, unless you are planning to change the bulbs to LEDs (although some newer Spectrums have one and sometimes both front and rear lights as LEDs. They can vary like this. I had a decapod with an incandescent headlight and an LED in the tender and no NMRA plug.)
4. Changing the headlight to LED in a Spectrum Steamer can be very, very difficult, particularly getting the shell open and off the loco without breaking something. Bachmann Support doesn't recommend trying to get the shell of some steamer models at all.
If you have an older Spectrum steam loco that needs to be hardwired one can still get enough access to the motor....it is just getting to the headlight that can be very hard. So I have just connected the existing incandescent headlight to the decoder in several. As mentioned check with the decoder instructions.
5. MORE DETAILS ON LIGHTS IN THE OLDER SPLIT FRAME DIESELS: You cannot leave the lights having a power contact with the top of the loco frame. With the older split frame diesels you have two choices: If your want to keep the existing incandescent lights, be sure to snip off the copper contact tabs that come down from the light board in the top of the loco shell to contact the top of the loco frame. You can solder the decoder light wires to the solder tabs that remain on the light board. Be sure to make your contacts where the resistors on the board are still in the circuit to do their job, that is, don't solder between them and the bulb. (Sorry, I don't have a loco open at the moment to add a picture).
or if you are interested:
It takes a little more time, but get a better light if you remove the light board and remove the bulbs. Then solder in the LEDs where the bulbs were at the ends of the existing light board. Now you have to remove the existing resistors (I tested this by blowing out an LED to be sure) because their rating is wrong for an LED. Replace them with the typical kind of resistor for an LED (750 ohm 1/8w or similar) as recommended by your decoder. Connect the blue and white decoder leads correctly to the LEDs for polarity as shown in many websites. Then screw the converted lightboard back into the top of the shell.
6. A drawback to connecting the lights in any fashion to the Spectrum diesels (existing bulbs or new LEDs) is that the shell is then permanently connected to the decoder on the frame by the light wires (unless you go to the trouble to add microconnectors that can be separated as needed to separate the shell completely). You sort of have to decide how long you want the light wires to be (because you will have to add to the blue and white decoder wires). I like them long enough to lay the shell upside down beside the loco because that makes the whole wiring process easy, but then I have to contend with rather long wires to carefully tuck out of the way when reassembling the shell and frame.
7. As always, test your conversion on a programming track before applying track power to your loco. I have to kind of balance the shell loosely atop the frame to do this.
Most newer Spectrum locos have an 8 pin plug in the tender. But beware of eratic throttle responce if you do not cut the cap from the spectrum board. Check out the TCS website for more info. WWW.tcsdcc.com. Click on instalation pictures.
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Hey guys,
I thought I better clarify what I was asking, I screwed up with an explanition of the engine I am wanting to convert. The engine in question is a 'Bachmann Spectrum F7 diesel that has a CAN Motor inside.'
If someone knows how to convert this engine, please let me know and what system you would recommend.
Black Sheep 25
A thousand Apologies for any confusion.