Older legacy - electrocouplers sometimes don't work

First off, many of them don't work with less than 16-17 volts on the track.  The older Legacy until around 2011 used the R4LC to fire the couplers, the later Legacy has the RCMC and a totally different coupler circuit and are more tolerant of low track voltages.

Thanks John for the formation.  I will have to check the on track voltage again.   My ZW-L shows just over 18 volts.  I run two lines - heavy wire.  Not to open a can of smoke.  (pun intended)   What smoke units did Lionel use and did they switch around 2011 also.    I have an older KLine that still smokes like an old sailor. 

Check the actual voltage on the track where the locomotive is, that's what will determine coupler operation.  You might put it on a test track with a direct transformer connection and see if they work there.

As for the smoke units, they use similar smoke units, but the smoke unit regulator circuit is all different.  The older Legacy used a discrete voltage regulator for the smoke unit in conjunction with modular electronics package.  Since 2011, Legacy has the RCMC, an integrated electronics board that handles all the the functions.

Gregg I have had the same problem.  You can try new Lionel couplers OR use MTH Proto 1 couplers.  They come in 2 lengths and I have used the shorter one to draw engines or engine to car distance closer together.  I have replaced Lionel Atlas and K-Lime couplers with MTH ones.  The MTH couplers tend to work better and kick the connected piece apart much better then old Lionel couplers.

For some balky couplers, I take them apart and smooth the operating surfaces.  This not only makes them work better, but they close much smoother and easier.  Done properly, you can couple up very easily without bashing the locomotive into the cars.

John and Bruce thanks for the help.   

I have noticed that the plunger spring in some couplers are a different gauge wire and stiffer than in others. These are usually the ones that are balky openers. Replacing the spring helps.

Finding a source for the proper springs is the tricky part Carl.   You're right, the spring should be a very weak spring, too much tension and they don't open.

When testing Lionel couplers before installation, is it ok to apply 16 volts ac to check if they work? 

Yep, just don't keep it on them long, they will over heat in a few seconds.  They get full track voltage for around 1/2 second in actual operation.  I test them at 12VAC, if they work on that, they'll work in almost any environment.

I checked track voltage at various spots - just under 18 volts on the entire layout.   I noticed when I do the couplers the lights on the unit blink.   Only having problems with this one train - 2009 Legacy SD80 -  worked before -  everything else works on train.    Some type of board issue?  To be honest the build quality on this locomotive has been not good in my view not sure if I will repair if needed to send in.

I'd actually suspect some conductivity issue with the wiring, not a board issue.  Look closely at the wiring from the pickup rollers to the motherboard.

gunrunnerjohn posted:

I'd actually suspect some conductivity issue with the wiring, not a board issue.  Look closely at the wiring from the pickup rollers to the motherboard.

Thanks John for your knowledge.  

Agree with John on this. Have a check of the wiring to the electro coupler.

I just had this issue with a early Legacy Lionmaster Challenger. I removed and reseated the coupler connector to the circuit board and it now works fine.

Nick