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Have a 20-3642-1, 3 rail/2 rail ps3 locomotive that has no track power (3 rail) going to the boards.  Center rail power goes thru the  drawbar to the tender and the outside rail has continuity in the tender.  I suspect the ground wire that is sticking up in the air on the left side of the attached picture is supposed to attach to the upper right connector on the 3/2 rail switch.  The service manual  chapter 11, pages 41 and 42 shows a wiring diagram.  The ground wire may have come off from somewhere.  I do not want to cause a dead short.

I suspect that it broke loose from the top row, right side.  The right side of that switch  is the 3 rail position.

Both engine and tender boards test good on my PS3 Test Assembly.

Can anyone be of assistance?

BruceLight Mikado switch


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  • Light Mikado switch
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I do not see which wire is broken on left, looks like heat shrink?  Anyway you need to trace the wires for sure.  Normally black to black.  The engine should send center rail pickup over one wire, and right side wheel on the other.  The left side chassis ground wheels of the engine make contact to tender via the drawbar metal pin that touches tender post.

Look at the solder joints on switch, one should show being broken, or have strands of wire still attached.  G

Bruce, your a tech.  That black jumper wire does no good on the switch with out an input.  So most likely your upper left black solder joint has a broken look to the solder where the loose black wire would join the jumper.  BUT trace it out.

As far as making it permanent 3 rail that is simple.  Get the center rail pickup wires and the ground wires going to the correct place.  I normally go in the engine and repurpose those right side wheel wires to AC ground with a jumper to the chassis.  Then both engine and tender provide an over the wire ground.

Basic wiring stuff here.   G

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