Need tether wiring diagram for K-line TMCC F3 6-motor ABA set K-25301

"By the way, despite having rollers on all 3 units, the power pickup is in the lead A only.  There are no wires connected to the rollers in the B and trailing A."

That doesn't make sense, what are they there for? Could there be wires missing? Is there any evidence of them having been soldered/connected to something before? Or did K-Line make all the chassis the same regardless of final usage?

Dave

DC power to the motors and lights is from the lead unit thru the tether.   They would have to add additional tether wires to tie together each units pickups for the center and outside rails.  These would carry AC of course.

The 2 pickups on the lead A unit are working fine even through some old gargraves turnouts.  

I may use the pickups to add additional lighting or other features.  Otherwise I would remove the pickups.

Bob

gunrunnerjohn posted:

I found that MTH, for reasons I can only imagine, wired the green and red front/rear markers in parallel!  OOPS!  

Wow!  That's a pretty basic goof.

Fully aware of the issues of running LEDs in parallel, I added headlights and tail lights in some 1:48 vehicles.  My supply voltage was not high enough to supply the 6 LEDs in series (the cars had double headlights).  So I ran 2 white LEDs in series with a red LED on each side and then connected the strings parallel.   This was put in series with a CL2 LED driver.  As you said, if the tolerances are tight you can get away with it.  All the white and the red LEDs were from single batches.   I actually got lucky and the first 4 cars were fine.   Then #5 failed.  Over the next few months something interesting happened.  2 of the first 4 cars had one string of lights fail (all the voltage goes to the other string).  Clearly not a good longterm strategy.  I'll use a CL2 in series with each string in the future.

John

Any thoughts whether the rear headlight circuit on the board in the lead unit might be an easy fix?  If not, I'll supply the headlight and number board in the trailing unit off of track power.

Bob

You can run them in parallel if you add in a series resistor to each string.  As long as the resistor drops more voltage than the difference between the lowest voltage LED string and the highest voltage LED string, they will light.  If you have limited current, you'll have to adjust the resistors to balance the lighting.

gunrunnerjohn posted:

So does Lionel and MTH.

I just got a RailKing subway set in for repair, a lot of the green marker lights didn't work for some reason.  Of the four cars, one worked perfectly, the other three all had issues.  When I opened them up, I found that MTH, for reasons I can only imagine, wired the green and red front/rear markers in parallel!  OOPS!  The green LED's run at a higher voltage than the red ones, so unless you got really lucky with the variances in the specifications, you didn't get green markers!  The difference isn't much, just .2 volts, just enough to screw things up. 

 

Model number please?  Is this PS-3 or PS-2?  G

I got it in a box without any ID, but it appears to be the 30-20301-1 PS/3 set. The guy bought it used, so he didn't have any warranty, though it's pretty new from the ship date. I was a bit surprised to see the sub-standard workmanship. One car was totally shorted as they had assembled the little P/S board incorrectly and it was wedged into the frame and melted the wiring. The engine and two cars needed a resistor tweak to allow all the lights to light.

Have to keep a lookout.  Is it possible it was modified?  G

I don't think so, the cars obviously had never been opened, and there was no sign that anything was tampered with.  You can almost always tell when you're opening a "factory fresh" unit, the screws are REALLY tight.   There would be no reason to modify them not to work I would imagine.