My 2343 Santa Fe F3 e-unit was not cycling. I removed the e-unit and found the drum could not rotate. On further examination, the black plastic insulating material in the e-unit drum appeared to be fractured and swelled so that the black material protruded significantly beyond the boundaries of the drum. I tried to press the black insulating material back into the drum with needle nose pliers, but it would not move. The e-unit teeth are all intact.
I have never seen a failure like this and I have no idea what caused the failure. The e-unit had been functioning normally the last time I tried it. I have been operating the loco in the forward position with the e-unit lever in the ‘OFF’ position recently. Has anyone seen a failure like this before and what do you think caused the failure?
I’ve run across E-units with distorted or shruken drums from time to time. I don;'t know the cause with any certainty, but I assume the problem is caused by contaminated plastic. I think the drums that I saw with the problem were shiney red or light green, with an appearance somewhat like celuloid.
Regardless, I don’t see any alternative to replacing the drum. I keep a supply of e-unit rebuild parts on hand, as they are commonly needed.
I removed the e-unit drum and attempted a repair because I don’t have a replacement drum. I used vise-grips to squeeze most of the black insulating material back into the drum. I then used a Dremel tool to grind off any remaining material that protruded beyond the drum. The e-unit is now working properly. I don’t know how long the repair will last. I will still replace the drum when I can get a replacement.
The odd thing is the e-unit was working fine when I purchased the engine about 2 months ago. When I tried to activate the e-unit yesterday, the drum would not rotate and I can see why. I have no idea what happened to the drum in the 2-month time period between when it was working fine and yesterday, when it would not rotate.
Thank you for the reply. I don’t recall seeing any evidence of a short in the two months I have had the loco. i.e. I didn’t see any erratic engine operation or flickering lights. The transformer is a modern ZW with 180W bricks. The bricks trip quickly whenever any short occurs on the layout. If there was sufficient heat to cause the distortion in the drum, the fingers should have showed some distress and they looked fine. I wonder if the previous owner might have sprayed some type of contact cleaner that might have attacked the insulating material. I am still puzzled by the condition of the drum.
I’ve never seen a drum that bad before. Even if the fingers don’t appear to be damaged, they may not be exerting enough pressure on the drum, which would lead to arcing and heat. I’d do a total rebuild on that e unit asap.
It is strange, maybe someone has the answer. I think a cleaner would have damaged all of the part. in this case the damage appears to be on one end and some of the cogs. Thus my heat theory.
I’ve seen one like that, too. Looked like heat did it to me, so I’ll go along with Sir James’ short theory. Mine was so mangled the drum had come out of its holes and was wedged in the e unit frame. There was some pitting (arc marks) on the two contact bands on the deformed side–they could be either pre or post mortem, tho. Dang, I was keeping that around as an oddity until just recently when I decided to toss it; woulda sent a picture. Oh well.
I have never seen a drum distort like this but I would also go along with the overheating theory. If it is due to overheating I would think that you would find one or more of the feelers to be overheated and distorted. It could have resulted from poor contact with the drum feelers (corroded contact, not enough feeler pressure or worn feelers). Another possibility is excessive current flow due to a binding or poorly lubricated motor, or from pulling too much freight for a long period of time. If you have an ampmeter, check the amount of current flow compared to similar engines. I would also recommend a new drum, 4 feelers and 2 feeler rebuild.
My first thought was aging of the plastic. Not all plastics are created equal and some crack or warp over time. Some vintage army men have proven my theory but I Vote for the heat on this one.
I checked both sets of fingers when I had the e-unit apart and they looked fine with no pitting or heat discoloration or distortion. I checked the current draw and the engine is drawing 2 amps at 10VAC at a normal run speed. The engine is a 2343 Santa Fe. It is pulling the dummy A unit and 5 postwar cars. All of the cars and the engines are well lubricated.
I often (like most every day) fall asleep when running my trains. So the train runs about 1 to 1 1/2 hours until I wake up again. The long run times have probably occurred on this 2343 engine less then a dozen times because I also run other trains on my layout. Maybe that is still too much running.
Earl, perhaps you should consider installing a shut off timer, such as found on bathroom heat lamp circuits, on your mauin layout powersupply. Not much point in having the trains running for a long time while you nap.[zzz]
I don’t know what it is, but I invariably fall asleep watching ‘O’-Gauge train videos too. It takes me three or more attempts at a train video before I will get through the whole thing.
I will invariably fall asleep when I go into my train room to run the trains after lunch. Naps with trains running in the background can’t be beat!
