Model Train Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Several of my steam locos from the MPC era (2-4-2s, 4-4-2s, etc.) have the 2-position E-unit with a double-wound motor field. These were all made during the 1970s. In several cases the E-units become balky and refuse to reverse once the loco has fully warmed up. It often takes multiple presses of the circuit breaker to change direction, and sometimes the loco will stall and take a pretty high voltage to get started again.

Has anyone else experienced this? The heavy die-cast 4-4-2s are the usual culprits, but even my plastic 2-4-2 gets balky once in a while. The 2-position E-unit has almost no parts; rather than the E-unit I suspect a brush contact issue, or something expanding with temperature. It's hard to troubleshoot because it seems to work fine with the shell off. Does anyone care to speculate on the cause and how it could be remedied?

P.S., I thought about installing the mechanism from a Postwar 249 which are very reliable. This would work for the 2-4-2, but the front wheels aren't quartered or tapped for the tandem driving rod arrangement on the 4-4-2. Thanks!
 

·
Admin
Joined
·
45,485 Posts
Have you used something like a silicon contact cleaner to thoroughly clean the plunger on one of the units? How about using a heat gun (carefully) or a hair dryer to heat up the E-Unit so you can see what's happening. It helps to block the locomotive up and connect wires so you can run it stationary. I use JAX blocks that allow me to run like it's on track, but it doesn't go anywhere.
 

·
Registered
Joined
·
1,266 Posts
I have not seen the MPC locomotive you have but your problems are typical of the poor quality trains MPC was producing during that era. :( Replacing the e-unit with a postwar three position version would be a definite upgrade. You may also want to consider installing an electronic e-unit circuit board in the tender.

This sort of thing makes me wonder how much money MPC (can you guess what I think the C stands for?) saved on 2 vs. 3 position e-units? I'm guess less than the cost of a couple of 16 inch softballs for the summer picnic. :D
 
1 - 3 of 3 Posts
Top