American flyer/Lionel 3 position electric reverse unit

Which number diesels are you inquiring about? Some early Lionel/AF diesels had double wound fields somewhat like the Gilbert originals. Succeeding models had can motors.

Rich

All these units have a can motor.  I am referring to the electronic reversing unit.   IC central GP20 SP GP20  SF GP20 and Chessie GP20//////////

A Dallee unit should work although nothing is cheap.

Rich

Purchased Southern Pacific GP9 on ebay.  Does not run Everything looks brand new ......no wear anywhere. Checked wiring AOK .  Next is to install a Lionel E unit  that I bought years ago.  I wonder what causes these electronic E units to stop working?   

Jackie

@William Jack posted:

  I wonder what causes these electronic E units to stop working? 

#1 aging capacitors- electrolytic capacitors age and change value and also can have failure of the capacitor even when sitting on a shelf unused. Capacitors are often used in the storing of the status bit to cause the unit to sequence. If it cannot store it or the capacitor is shorted- then the circuit doesn't work.

#2 many of these used BJT transistors. A known issue of the BJT is thermal runaway. As current load is increased and temperature of the transistor junction rises- this causing even more heating in a self destructive feedback loop known as thermal runaway.

Follow up convo

What makes the Dallee reverse units different from the Lionel version? I'm not trying to endorse, just saying at a technical level what makes it different or better.

#1 uses small multi-layer ceramic and modern solid state capacitors rated for much, much, much longer total lifespan than older electrolytic capacitors.

#2 Uses MOSFET transistors which have much lower on state resistance, massively less heating than a BJT https://www.farnell.com/datasheets/2354030.pdf

Again, I'm just trying to give a fair technical reason- why do older electronic E-units fail, what was specific about that design, what is different about the 3rd party modern electronic E unit that makes it more robust and less failure prone over a long lifespan.

Bottom line- yes, the world got better at electronics and over time better more efficient and long lasting components were developed.

I’ve replaced a few of those E-units.  I’ve bought replacements from Jeff Kane (www.ttender.com) that work, but a Dallee 400 is a good substitute.