I have several boxes of unused equipment and unbuilt kits that I acquired for my previous layout which I dismantled before putting them to use. One of those items is an Athearn BB Trainmaster which I acquired shortly before I began dismantling the old DC layout and which has never been out of the box. I haven't even put the stanchion on it yet. My current layout is DCC and I recently replaced a basic Digitrax DH126 decoder with a LokPilot on one of my C-Liners so I have a spare decoder and thought I might as well put it to use and add the Trainmaster to the roster. It seems to me that I read in these forums some issues with installing a decoder in a BB loco but I can't remember specifically what those were. I think it had something to do with making sure to isolate everything from the frame but I'm fuzzy on the details. Is there something I need to know about putting a decoder in an Athearn BB loco.
Also, as I remember from my previous layout, a KD #5 was not a good fit for a BB loco but I never did figure out which KD should be used. Does anyone have the answer to that.
John,
You want to verify/make sure that the (+) & (-) motor contacts are completely isolated from the chassis. Otherwise, you run the risk of frying your decoder if you short it at a turnount or from a derailment. You then solder the motor wires onto the motor contacts of the decoder, or the orange & gray wires coming from the decoder.
The Kadee Athearn HO-Coupler Conversions webpage states to use a #37/#147 coupler and the #252 gearbox.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Hello All,
John-NYBWI have several boxes of unused equipment and unbuilt kits that I acquired for my previous layout which I dismantled before putting them to use. One of those items is an Athearn BB Trainmaster which I acquired shortly before I began dismantling the old DC layout and which has never been out of the box. I haven't even put the stanchion on it yet. My current layout is DCC and I recently replaced a basic Digitrax DH126 decoder with a LokPilot on one of my C-Liners so I have a spare decoder and thought I might as well put it to use and add the Trainmaster to the roster. It seems to me that I read in these forums some issues with installing a decoder in a BB loco but I can't remember specifically what those were. I think it had something to do with making sure to isolate everything from the frame but I'm fuzzy on the details. Is there something I need to know about putting a decoder in an Athearn BB loco.
One of those items is an Athearn BB Trainmaster which I acquired shortly before I began dismantling the old DC layout and which has never been out of the box. I haven't even put the stanchion on it yet.
My current layout is DCC and I recently replaced a basic Digitrax DH126 decoder with a LokPilot on one of my C-Liners so I have a spare decoder and thought I might as well put it to use and add the Trainmaster to the roster.
It seems to me that I read in these forums some issues with installing a decoder in a BB loco but I can't remember specifically what those were.
I think it had something to do with making sure to isolate everything from the frame but I'm fuzzy on the details. Is there something I need to know about putting a decoder in an Athearn BB loco.
(Breaking up large blocks of intimidating text into more readable sentences makes answering questions easier.)
Have you removed the shell to see what you are dealing with as far as space for the decoder?
Yes, you will need to electrically isolate the motor power from the frame path.
With DCC decoder installations the power from the track needs to first pass through the decoder from the wheels (black & red wires on the decoder) then from the decoder to the motor (gray & orange wires).
If the motor is not electrically isolated, to allow the decoder to perform its intended function- -in this case- -motor control, you will fry the decoder.
When it comes to electrically isolating the motor I'm a "suspenders & belt" kind of guy.
The motor brushes are held in place with clips.
On the top of the motor, this clip runs between the two (2) gear towers of the trucks with an L-shaped bracket to transmit one side of the track power to the corresponding side of the motor.
The clip on the bottom of the motor has two (2) prongs that connect that side of the motor to the frame. The wheel contacts on that side of the trucks, through another L-bracket, connect directly to the frame, making the frame an electrical path.
Good for DC, bad for DCC.
To isolate the motor from the frame the L-brackets from both the top of the trucks need to be cut. I use diagonal cutters to perform this surgery.
I also "shorten" the top bracket so it only holds the motor brushes in place resulting in no contact between the top L-brackets of the trucks and the top clip of the motor.
Then, I push the two prongs from the bottom motor brush clip flush, with the tip of a flat blade screwdriver.
I also swap the bottom motor brush clip with the top- -shortened- -motor brush clip.
To ensure complete motor isolation I apply a coat of Liquid Electrical Tape to the inside of the frame. Again, "suspenders & belt".
Now the motor is completely isolated from the frame.
I then solder wires; red & black (NMRA standard) wires from the nubs of the previously cut L-brackets; now isolated track power, and connect them to the corresponding wires to the decoder.
The motor outputs (gray & orange) of the decoder are then soldered to the corresponding; positive & negative motor brush clips on the now isolated motor.
If, when testing the now installed decoder, the unit runs in the opposite direction of the DCC controller, I don't change the CVs. Insted, I resolder the orange & gray wires to the opposite motor brush clips.
This way I don't have to remap the lighting functions.
Good luck, and as always...
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Hello
While this example shows a BB SD9 the procedure will be similar and these photos will supplement the advice given above by jjdamnit:
https://tcsdcc.com/installation/ho-scale/1070
Remember to carefully remove the motor brush clips before soldering!
Good luck soldering to the plated steel truck contacts. Try to file away some of the plating, use flux and plenty of "localized" heat and pre-tin the spot where the wire will attach. Clip a heat sink between the tab and the truck (needlenose pliers with a rubber band around the handle)
I don't trust vinyl electrical tape to insulate the bottom motor location. Clip the prongs as jj advises but use Kapton tape, two layers actually, to insure it never gets compromised.
Good Luck, Ed
I would order some of these from Athearn. Replaces the old push in motor mounts.
https://www.athearn.com/Products/Default.aspx?ProdID=ATH84028
Thanks for posting that link, ba&prr! I have two Stewart "Athearn" chassis and that will be replacing the soft motor mounts on both of them.
gmpullmanI don't trust vinyl electrical tape to insulate the bottom motor location.
Neither do I!
That's why I recommended Liquid Electrical Tape.
If you are not familiar with this product it is a thick, viscous, liquid that is "painted" on with the brush built into the cap.
Multiple layers can be built up, thus providing a greater electronic barrier.
Unfortunately, this is an acetone-based liquid and gives off strong fumes while curing.
Allowing to cure in a well-ventilated area or outdoors is definitely advised.
gmpullman...use Kapton tape, two layers actually, to insure (SIC) it never gets compromised.
I too am a big fan of Kapton Tape.
Unfortunately, in areas of friction or movement between components I have experienced a breaching of the material.
Multiple layers help.
In areas where I know movement (friction) may occur I prefer multiple layers of Liquid Electrical Tape.
I don't mean to be contrary. I just wanted to clarify the difference between electrical tape: vinyl or PVC, and the Liquid Electrical Tape product.
Thanks to all for all the excellent suggestions. I thought I remembered reading about issues with decoder installations in a Athearn BB diesel but couldn't remember exactly what they were. On my old DC layout, I had lots of BB diesels and as I remember, they all looked very similar on the inside with the size of the components being the primary variable. I cleaned house last year and sold off most of my BB diesels to my LHS. Didn't get a lot for them but I didn't expect a lot.
The Trainmaster was one I held on to because it was unused even though I think I bought it about 25 years ago. It should be an interesting addition to the roster. It will be my only 6 axle diesel and I'm going to repaint it for my fictional railroad, a basic black with some gold trim.
I have plenty of Kapton tape and I just located my jar of Liquid Electric Tape which I've used before. I'll put both to good use on this project. I intend to follow the "suspenders and a belt" approach. Insulating tape is very cheap compared to the cost of even a basic decoder.
jjdamnitNeither do I! That's why I recommended Liquid Electrical Tape.
Your methods are good , I was mainly pointing out the somewhat sloppy use of the vinyl tape as depicted in the TCS photos shown on their site.
On the lower motor clip, I flatten out the sprong part of the clip and solder it so it is flat. There is no way the clip can touch the frame then.
woodone On the lower motor clip, I flatten out the sprong part of the clip and solder it so it is flat. There is no way the clip can touch the frame then.
I converted my first Blue Box loco today, an SW-7. I just swapped the top with the bottom springs then soldered the orange/grey wires to the copper strips. I did cover the frame where the motor sits with kapton tape for extra protection.
Joe
Modelling 70's Rock Island in the UK