MTh SUper 381E - nice loco - dead short

I always look at the pick-up wires rubbing where they enter the frame on their O scale engines. I've not worked with these.

I feel your pain Jim, it’s a pain sometimes maybe try running it without the shell to see where loose wires tend to rub etc. 

Yes, it can be run without the shell.  Four screws secure the center frame, two tabs at each end and four plugs for the lights.  Just worked on one Friday.  If it still shorts, look for pinched wires or one pickup shorting at the tab near the rollers or the spring contact inside the pickup.  If it's conventional, the solder tabs on the armature can contact the tab for the spring pickup.

Jon G posted:

Yes, it can be run without the shell.  Four screws secure the center frame, two tabs at each end and four plugs for the lights.  Just worked on one Friday.  If it still shorts, look for pinched wires or one pickup shorting at the tab near the rollers or the spring contact inside the pickup.  If it's conventional, the solder tabs on the armature can contact the tab for the spring pickup.

Jon - was hoping to hear from you and thanks. Two Bild a Loco DC versions. I'll pull the plates off the bottom of each and see what I can see.

Thanks a bunch

Jim

Dennis Holler posted:

I feel your pain Jim, it’s a pain sometimes maybe try running it without the shell to see where loose wires tend to rub etc. 

Good idea Dennis - should have done that the first time, but these aren't too hard to pull apart.

Jim

Follow up: started by removing each of the bild a loco base plates. THERE was the culprit - the spring for the contact rollers was making contact with the frame of the baseplate - on the end. Chinese quality control at work. The sheet metal baseplate bends in with a slot for the fiber insulator at the end of the spring - not bent at at 90 degree angle.

I got to do my 'red and tacky' and oil thing while in there. No shell removal this time.

Pulled out a couple of State cars just to check. All is good.

Thanks Jon and Dennis for your help!

Jim

Jim Waterman posted:

Follow up: started by removing each of the bild a loco base plates. THERE was the culprit - the spring for the contact rollers was making contact with the frame of the baseplate - on the end. Chinese quality control at work. The sheet metal baseplate bends in with a slot for the fiber insulator at the end of the spring - not bent at at 90 degree angle.

I got to do my 'red and tacky' and oil thing while in there. No shell removal this time.

Pulled out a couple of State cars just to check. All is good.

Thanks Jon and Dennis for your help!

Jim

Jim,

Glad to hear you got it going.

If you get a chance post a movie.

good eye. stuff like that is hard to see.

You guys are too fast. The Build-a-loco pickup plate is always a problem with MTH. It happens to me on my 400e all the time.

George

This is a problem on some of the build a loco baseplates.  The later ones should have the an extension of the insulator under the spring contact to prevent it from shorting on the baseplate frame when the contact is depressed.  If it doesn't, I glue a piece of insulator under the contact.