I have an ancient Athearn Blue Box SD40-2 in Conrail paint that in recent time has started to act like the prototype-terrible. While it still runs, the motor is old and worn and has a hard time getting the unit to move at all. It has stalled many a hook up to a train, and since I’m replacing my power pack, should I have my unit rebuilt or scrapped?
Have it rebuilt. It’s not hard to change out the motor. Get a replacement motor that already has the flywheels attached. You’ll save yourself from some aggravation. While you’re at it you might consider converting it to hex drive.
I still run several Blue Box SD40-2’s on my layout with the original motors with circuit boards from the newer RTR units… I also have the newer RTR SD40-2’s. You could try to swap motors from a RTR SD40-2 with the hex drive shafts and circuit board. Go to Athearn’s web site and look for parts, or maybe eBay. Earl…
Several things come to mind.
First off, the electrical pickup arrangement with the sliding contacts between the motor top strap and the power strips coming up from the trucks. You ought to hard wire that path just on general principles. Get some 1/4 inch “Fastons” from your local hardware store. They slide onto the truck power strips. Run wires from the Fastons to the top strap and solder them.
Check out the gears in the gear towers. Clean thoroughly to remove tiny bits of invisible black plastic flash from the gear trains.
Clean the commutator with GooGone.
Check the brushes and replace if necessary.
Remove any flash from the drive shafts and U- joints.
Clean the wheels.
The SD40-2 had scale hood width, and very decent detailed sideframes for the trucks. In other words, many of the reasons why guys decide to retire a worn out Athearn EMD don’t apply to the SD40-2. I’d remotor.
Dave Nelson
Thank you all for replying. I think I’ll see what the new power pack does with the old beast. The new pack is a MRC Tech 4 280 Dual Power. If it still won’t run eith the Tech 4, I’ll have the motor replaced.
B30
How old is it? If it is rubber band drive I would up grade the drive system to gear.
If you are DC and like the engine it is worth up grading! Like others I would clean it real well, check the brushes and clean the armature before I decided to re-motor.
You will spend around $30.00 to $40.00 for a new motor and today unless you are real lucky that won’t buy much of a engine.
If you are DCC, that is a different question with it being a hot frame.
DC is so much easier to fix, but I still love DCC so I am not starting a war.
Cuda Ken
Ken,The SD40-2 was never equipped with a rubber band drive…
The SD40-2 is one of the better BB locomotives and its right up there with the SW1000,SW1500,GP38-2 ,GP40-2 and the GP50…
While the other BB locomotives are nice I fully believe Athearn out did themselves with the above mention locomotives.
Before you go replacing the motor, have you tried giving it a tune-up? If the motor works at all, it can be made into at least a decent runner again.
Are the brush springs giving sufficient tension on the brushes, or have they flattened out? If they’re flattened, stretch them back out until they stick out of the motor about 1/4" without the brush clip.
Is the commutator (segmented part of the motor where the brushes touch) clean and free turning? If not, you can clean it up with TV tuner cleaner (I think), or maybe alcohol. It should be bright and shiny.
Have you oiled all of the motor and worm bearings?
If the motor’s hopeless, you can get a new one from Athearn. There are also remotor kits available from A Line, Helix Humper, and NWSL. They sell anywhere from $30 to $50, depending on what you get, and they’re all very good quality options.