My last wiring question, I promise!

[rha90272]

I'm wiring up a number of Lionel O-gauge UCS control tracks. I hook up wires 1,2,4 (from left to right, coming out of the controller) to terminals 1,2,4 of the UCS track (numbered left to right). I hook wire 3 from the controller to a fixed 15v power terminal, for steady power independent of the variable voltage to the track. That same fixed power terminal also powers the fixed voltage plugs on the switches.

When I push the "unload" button, it works as it should. But when I push the "uncouple" button, all the lights dim (nearly out) on all the switches, as if I've got a short. Variable voltage to the track is unaffected.

I've tried this with two different new controllers, and two different new UCS tracks, so I don't believe it's a short in either the controllers or the UCS tracks.

This seems so simple. What is going wrong? Thanks for any help.
Bob A.

[chuck]

Have you tried testing the UCS tracks independant of the rest of the layout?  The coil used for the uncoupler magnet does pull a lot of power and if held continuously might have suffered damage.  The enamel coating on the coil wires may have started to degrade and the coil is partialy shorting out internaly.

[lionelsoni]

The coil operates for both uncoupling and unloading; so I doubt that a bad coil is the problem.

[chuck]

Pulled out my copy of the Greenberg PW repair/operating manual.  There are a couple of notes regarding wiring for fixed voltage operation including warnings about use of a common ground and variations on the controller regarding the use of pins 3 and 4.  These were "switched" for mechanical reasons and the change is only important to note when used in a fixed voltage envirnonment.  This is covered  on pages 636-640.  You can probably download the same info from Olsen's library:

http://pictures.olsenstoy.com/first.htm

Select Library from the blue/gray bar near the top of the page

[lionelsoni]

Here is a link directly to the UCS schematic:

http://pictures.olsenstoy.com/cd/swt/stcrcs3.pdf