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Broadway Limited Sharknose - 21 Pinout Questions.

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gregeusa:

G8B4Life:

--- Quote from: OccamsRazor on August 05, 2024, 06:09:31 PM ---Sorry...

I tried to upload them as JPG but the system said they were too big. GIF. Same... :o The only thing GIMP would convert them to that was remotely within the size limit and that the system allowed me to upload was WEBP :(

--- End quote ---

No need to apologise, you weren't to know. I don't know how a JPG was "too big" though, unless you had no compression at all; the maximum size per image here is quite generous.

Anyway after looking there are a couple of things.

1. You've put the front light (J1:Pin 2) on output 1 (White) which is standard but you've put the rear light (J1:Pin 3) on output 4 (not standard) instead of output 2 (yellow). There is nothing wrong with this but understand that if you use automatic change headlights on direction then this won't work, the front headlight will go out on changing to reverse but the rear light will not come on. In your case the front markers will change because you've got them hooked up to output 2.

2. You've had the Common hooked up to a wire labelled +3.3v. I hope you have not damaged whatever's at the end of that wire that's expecting 3.3v and not the near 15v that you gave it.

Just sitting on the track in the forwards direction do the front and rear headlights work? From what I can see that you've done they should as J1 appears to be designed for amplified outputs.

This leaves everything attached to J7. Going by the inclusion of +3.3v and ground on this jumper I'm lead to believe that these are designed for logic level (+5v) outputs (which is a thing with 21MTC decoders). RailPro obviously doesn't have any 5v outputs. If you follow the wires for pin's 1, 2, or 3 on J7 you should, if I'm correct, find them connected to some little transistors (which could even be on the bottom of the motherboard).

Without knowing what's on the end of the wires (just LED's, a circuit board with other components on it etc) it's hard to say any more.  I guess trying to map the pins of the 21MTC connector to the pins in the jumpers is not a possibility?

- Tim

OccamsRazor:
Okay...

Pulled out the multi-meter and traced out all of the lighting circuits.

Immediately found my problem!

Turns out that the J1 and J7 sockets go to a row of surface mount resistors on the bottom of the MTC motherboard, (to reduce the voltage to the lights I am guessing). Bypassing the board was feeding a straight 13-15 Volts to the lights, (causing an "Output Short" error), and not making them very happy.

The Rear Light cluster is simple. Two wires. (J1:Pin4 = Rear Anode = RP Blue Common + and J1:Pin3 = Rear Cathode = RP Output 4 Violet) Since they are LED's and don't appreciate being zapped with 13-15 Volts I installed a 1k Ohm 1/4W resistor on the Cathode and Bob's Your Uncle!

The Front Light cluster was a bit more involved.

The mini light board has some surface mount resistors for the Frt Light but they DID NOT reduce the voltage! (Ask me how I know! :( ) Not sure of the resistor value or if they are supposed to add in serial to the resistors on the MB or if they are there for some other function?

Anyway... Frt. Mini Light board is:
J7:Pin5 = Common +3.3V for the Anode + of the # Boards and the Front Markers. (NOT FOR THE FRT LIGHT!)
J1:Pin1 = Front Light Anode +
J1:Pin2 = Front Light Cathode -
J7:Pin1 = # Boards Cathodes -
J7:Pin2 = Marker Lights Cathodes -

Soo... With the replacement of one burnt out headlamp later I ended up with:

J7:Pin5 to the RP Blue Common +.
J1:Pin1 to the RP Blue Common +.
J1:Pin2 with a 1k Ohm 1/4W resistor to RP Output 1 (White)
J7:Pin2 with a 1k Ohm 1/4W resistor to RP Output 2 (Yellow)
J7:Pin1 with a 1k Ohm 1/4W resistor to RP Output 3 (Green)

(Hence the reason why the Rear Light is on Output 4 (Violet). (See! There is a method to my madness!)

Now everything works! Even bidirectionally! I even added the MARS light feature to the front light even though I am not sure if the B&O Sharknose used one... Sue me!  ::)

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