Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
good job!
all my old pancake versions were retired long ago, replaced by the spectrum version, but if I run across any more, I'll know how to update them.
I finally finished repowering my old Bachmann DD40 with a better mechanism. Now that it's done and working, I thought I'd post a "how to" topic on how I repowered it.
The original 4-wheel-drive mechanism was a poor runner, no matter how much I did to make it better (it does run a little better than before, but still not great). I decided to repower mine with Athearn trucks and a pair of good quality (yet inexpensive ) Mabuchi motors with flywheels.
I had to completely cut out the sections of the frame where the old trucks were mounted, and make separate frames for each truck, kind of like an old Mantua diesel. The motors are mounted on each end of the fuel tank, using flipped over A Line stick on weights, which are glued to the frame. The tape on the bottom of the weights is the same as what A Line sells for motor mounting, so you don't have to worry about the motors coming loose.
I used parts cut off from the Bachmann sideframes and some extra brake cylinders to detail the Athearn trucks. It still doesn't look quite like the DDA40X trucks, but it's close enough to look good. You can also see what the home-made front truck mount looks like in the picture. All the Athearn wheels were replaced with NWSL 40" wheels, which roll quieter, look better, conduct electricity better, and grip the track more.
I had to move some of the parts on the PC board around just enough to clear the flywheel. Some were as easy as bending them out of the way, but the large black cylinder-shaped part had to be partially unsoldered and moved closer to the PC board.
To support the front truck, I had to put whatever I could in the bottom of the cab. The stick-on lead worked well for the large open area, and then I filled the steps with whatever I could find, which was some extra plastic from a model truck.
To make the DD40 look a little more realistic, I made the walkway in the middle of the hood out of some copper sheet and glued it in place, making sure it was properly lined up with the doorways in the shell. It really does make the engine look a lot better.
All assembled! Everything is held together by super glue, so it should hold together fine as long as I'm careful. I filled the front pilot, but the rear pilot was left open so it wouldn't drag cars off the track on curves. Some of the rear coupler box had to be cut off to clear the shell.
Since I used Athearn trucks, it's not a real quiet runner, but that should hopefully improve with some run time. Other than the noise, it's now an excellent runner. The speed control is excellent, it runs smooth at all speeds, it draws less than 0.2 amps running free (which surprised me), and with a weight of, I'm guessing, over 2lb. and 16 wheel drive, it should be one of my strongest pullers. I probably spent between $70 and $80 on everything, and the engine originally cost me only $5 at a train show. Even so, I'm happy with how it turned out.
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