Hey guys
Im having a problem with my Atheran GP-38. The problem is that there is no power to the rear truck the front one is fine but nothing in the back. I have checked everything the clip is touching the metal clip on the truck So im stumped to what the problem can be???
any help would be great
thanks
Jeremy
Have you checked the truck pivot? Athearn locos use the truck pivot as one conductor and the metal strip across the top of the motor as the other (replacing this strip with wire is a good idea too). I had this problem with my DD35A where one truck pivot was slightly bent, causing the loco to wobble and not pick up properly. Best way to check this is to take the rear truck off and check if the pivot is level - use a pair of pliers to gently straighten it if it’s not.
Hope this is of help!
Make sure the top cover of the gear box on the truck is firmly in place and is holding the worm gear down. It does not take much free play or a loose cap for the worm gear to disengage from the gearbox, causing that truck to lose power. If necessary, remove the top cover and make sure the worm gear bearings are properly seated, and then snap the cover back on.
Truck wiring is one side of wheels to the tab, tab to motor, motor to frame and the return is frame to truck frame to other side of wheels. You more likely got something in the truck itself which is either binding the gears or is not allowing the worm gear to make contact. Start with removing the truck and seeing if it move freely. The smallest of debrise can stop it. I’ve just had to disassemble a rear truck for an Athearn SW1500 which had a plastic chip in there from somewhere.
I have tried these suggestions and still nothing, Im really stumped on this one
Jeremy
When you say there is no power to the truck, do you mean mechanical motion from the motor, or that it has no electrical pickup? My earlier suggestion was assuming you meant the truck was not being turned by the motor. If you meant no electrical power pickup, it might be caused by dirty pickups. Most Athearn locomotives pick up their electrical power from the truck through a bronze wiper that touches the axles, and if a lot of dirt got into this part of the truck, it might be acting like an insulator. Without disassembling the truck, it’s hard to see if this might be the problem. If you have a voltmeter that can test for continuity or resistance, check the reading between the wheels and the metal bracket on the truck. If you get an Ohms reading of infinity or the continuity check doesn’t produce a tone, then the truck will have to be disassembled and cleaned.
Sounds like a broken shaft or ‘U’-joint. Possibly the shaft just slipped out of one end or the other at assembly.
JeremyB,
I can think of two things that might have happened.
1 - There is a gear missing from the truck. I know this is unlikely, but I have a DD35 that is still missing a gear from the front truck.
2 - The universal joint in the flywheel is “freewheeling”. The plastic inserts in the flywheel can sometimes break free from the metal of the flywheel. It looks OK, but just turns inside the flywheel. It could be either the end with the drive shaft from the motor or the end with the universal. The drive shaft to the truck keeps everything in place, but not tight. I bet this is your problem. If it is, replace the flywheel
Mark C.
Super glue the plastic u joint onto the shaft…it’s loose either at the flywheel or on the wormgear of the affected truck…yo9u could rough up the shaft with some sand paper first if you want.