PS1 Bottom Board Coupler Won't Fire

Well, couple of things.

#1 the upper PS1 board is what triggers this to fire. So it could be a connection to the upper board or even firmware or setting problem. Did you also do an 18 Reset?

#2 The transistor is UNDER the huge capacitor, so you have to remove that first (sometimes they used hot glue). The capacitor is part of the circuit and stores track voltage- Just saying be careful that huge cap may still have decent charge in it.

Side view- again under the capacitor

Also see PS1 troubleshooting https://mthtrains.com/sites/de...shooting%20chart.pdf

Again, key in there is option 10

Remember, these resets are the chip and upper PS1 board. The lower power board you have pictured doesn't store or retain any settings. It's outputs and functions are all controlled by the upper PS1 logic board.

HI if coupler wont fire generally the capacitor is defective! they use FET for coupler triggering!

Alan

Thanks Vernon & Alan for the technical help.

I will fit a good top board to this bottom board, and see what happens.

And yes....I found out about stored voltage in these capacitors the hard way. I checked this one with the multimeter and got good readings, so I can rule out the capacitor.

I will also try the "feature 10" reset, and see how that goes.

Thank you again gentlemen.

Peter.....Buco Australia.

Update:

Added a good top board, and when powered up on my test station, it had distorted sounds. Shut it down immediately and took a closer look at this bottom board.

That's when I noticed the 337 regulator was very loose, to the point where I could easily remove it with my fingers. Looked at the "traces" on the circuit board where the three prongs of the regulator connect, and I could not see any of the trace material left at any of the connection points.

There was no point in trying to resolder the regulator back onto the board, as there is no continuous trace on the board to complete the connection.

This bottom board is now relegated to the "spare parts" bin.

Thanks for everyone's help.

Peter.....Buco Australia.

YOU'RE welcome Buco! Alan

I believe you first have to go to "full throttle" (~18V) in neutral to "arm" the coupler fire. From the Premier PS1 FM Trainmaster manual:

1. Put your engine in NEUTRAL and turn the throttle all the way up.
2. Press the transformer whistle button to “Arm" the coupler. (You
will hear a “Clank").
3. After arming the coupler, press the whistle button again to open
the coupler.

When the knuckle fires open you will hear the buzzing of the coil energizing and the sound of the air lines coming apart. It can best be described as a CHA-CHUSHHH sound. The coupler doesn’t have to be fired in NEUTRAL. Once the coupler is armed it can be fired in Forward, Neutral or Reverse. However, you may find that the coupler doesn’t open when firing the coupler at high speeds. Reduce the voltage setting on your
transformer if this occurs and run your engine at a slower speed before firing the coupler.

This works with my Premier PS1 FM Trainmaster on my Z-1000 controller. You also need to ensure that the "two-arrow" switch (across from the smoke "on-off" switch) is set with the switch pointing to the coupler you want to operate.