K-line Plymouth Switcher Smoke Unit questions

Quite sure unit does not have a fan

Smoke just puffs as it goes around.

They are fan driven! 🙂 It's super impressive the smoke output in such a tiny loco. I didnt have the housing or motor in the picture unfortunately.

Here's a video of another one in the fleet!

39 ohms is correct. They are powered by track power. It does have a small fan like a window fan, not a typical squirrel cage fan. Might just be stuck. Fan runs on 5v on the pc board its mounted on.

Pete

Thank you for verifying the smoke resistor! The motor fan is good I bench tested that. The 10v cap was no good I tested it with my Peak capacitance meter.  Just couldn't find any information on that resistor and mine is alot bigger than the ones in pictures online

FWIW, I've found that for some reason K-Line screwed up the design of the smoke power supply on at least one run of those.  They wired the filter capacitor AFTER the regulator, which or course feeds the regulator half-wave unfiltered DC power from the diode.  This makes the regulator useless, and it doesn't take that long to cook it.

The cap should be a 35V capacitor and wired between the output of the diode and ground before the regulator.  The 10V cap you found is a dead giveaway that you have the screwed up wiring!  Don't bother putting it back together the way it was, you'll have the same problem soon.

@gunrunnerjohn posted:

FWIW, I've found that for some reason K-Line screwed up the design of the smoke power supply on at least one run of those.  They wired the filter capacitor AFTER the regulator, which or course feeds the regulator half-wave unfiltered DC power from the diode.  This makes the regulator useless, and it doesn't take that long to cook it.

The cap should be a 35V capacitor and wired between the output of the diode and ground before the regulator.  The 10V cap you found is a dead giveaway that you have the screwed up wiring!  Don't bother putting it back together the way it was, you'll have the same problem soon.

Thank you very much for the information! I saw the post about yours (and the awesome tmcc one too
) and was hoping it wasn't the wrong wiring version lol. Is it an easy diy fix, using the correct 35v cap?

@p8ntballer789 posted:

Thank you very much for the information! I saw the post about yours (and the awesome tmcc one too
) and was hoping it wasn't the wrong wiring version lol. Is it an easy diy fix, using the correct 35v cap?

Yep, you just have to do a couple trace cuts and wiring to wire it up like it should have been done.  I had two of them that had the same screwed up circuit board.  I hacked up a diagram I had, here's what the regulator should be wired like.  C1 is a 35V cap.

@gunrunnerjohn posted:

Yep, you just have to do a couple trace cuts and wiring to wire it up like it should have been done.  I had two of them that had the same screwed up circuit board.  I hacked up a diagram I had, here's what the regulator should be wired like.  C1 is a 35V cap.

THANK YOU!!! I will give it a shot and hopefully revive another loco, thanks to you!

Might actually be easier to leave a cap on the regulator output and add another on to the input after the diode. Typically the three terminal regulators use them in both places with the larger one on the input

https://www.ti.com/lit/ds/syml...Fwww.google.com%252F

Pete

@Norton posted:

Might actually be easier to leave a cap on the regulator output and add another on to the input after the diode. Typically the three terminal regulators use them in both places with the larger one on the input

https://www.ti.com/lit/ds/syml...Fwww.google.com%252F

Pete

Appreciate the information and spec sheet! Will have to look into this as well

@p8ntballer789 posted:

Appreciate the information and spec sheet! Will have to look into this as well

The values aren’t that critical so to a degree bigger is OK. One other reason the regulators are failing is having to deal with the half wave rectified. No cap and half wave means two strikes against it.

Pete

If you guys don't mind me asking, is this new board I recieved the "correct" board? (labeled new in sharpie, and has blue cap) It has a 10v cap on it, like my bad board.. Trainz had it for $15 so added it with my order. The traces look similar but I'm still a rookie with this stuff. Thanks for all the help!

The new board is the same as your old board. You need to add a cap to the input of the regulator. Input is tied to the cathode (line) of the diode. Plus side of the cap goes there. Negative side of the cap goes to center lead of the regulator, not necessarily right at the regulator but to the ground plane that its connected to. Trick will be to make sure the smoke unit and shell clears it.

Pete

The screwed up with their "update", how quaint.

Thank you Pete and John, really appreciate you both taking the time to teach me how to repair them! I will attempt to correct both boards once the workbench clears up. I think I like repairing/tinkering more than running trains sometimes Thanks again!