Athearn RTR 21 pin Light Board Outputs

[nebrzephyr]

Does anyone know how the "tabs" labelled F3, F4, etc on the Athearn 21 pin light board correspond to the pins on a 21 pin decoder? For example, pin 15 on the decoder is AUX1 (Output 3), but what tab on the light board corresponds to that? I haven't been able to figure it out, probably something simple I'm missing.

TIA. Bob

[edwardsutorik]

Seems you could figure that out with a VOM, used as a continuity tester. Clip one probe to the tab labelled F3, and start going down the holes in the jack until you find the one (and only one) hole that is continuous.


Ed

[jonklein611]

Some info in this thread:

atlasrescueforum.proboards.com/thread/7165/new-athearn-loco-pin-adapter

It appears that the new Athearn light board pin outs match the 21 pin standard. For example, by default AUX1 is mapped to F3. So, I have this engine configured F0= head light (both directions), F1= rear light (both directions), and F3= ditch lights.

Careful, there are two 21 pin standards:

The discrepancy between the standards really ONLY affects AUX3 and AUX4. Technically it affects all Group 8 Functions but TCS and Soundtraxx do not offer decoders that use AUX5 and AUX6 at this time.



This means the differences in the standards generally only apply to 6 (or more) function decoders.



The net effect you will see if using an incompatible combination is that AUX3 and AUX4 will not work properly.



All other features of any decoder remain the same and are fully compatible with any model.



If you don't need any of this for your application, none of this matters.



If you do, validate your application and shop wisely.

NEM660 and NRMA:

www.sbs4dcc.com/tutorialstipstricks/21mtcconnector.html

[nebrzephyr]

Thanks guys for the info. Have it figured out now.

Bob

[amsnick]

Hi,

When you want more working outputs or functions the Decoder Buddy will provide 8 outputs that all work well with LEDs. There are, on request 0 ohm resistor boards available that can be used with 14 volt lamps and LEDs with resistors already installed in line. There is also a 750 ohm version for 1.5 volt lamps found in older locomotives. Make your request by email at www.nixtrainz.com they are not available elsewhere at this time.

Nick

[nebrzephyr]

Jul 5, 2019 11:42:08 GMT -8 amsnick said:

Hi,

When you want more working outputs or functions the Decoder Buddy will provide 8 outputs that all work well with LEDs. There are, on request 0 ohm resistor boards available that can be used with 14 volt lamps and LEDs with resistors already installed in line. There is also a 750 ohm version for 1.5 volt lamps found in older locomotives. Make your request by email at www.nixtrainz.com they are not available elsewhere at this time.

Nick

Thanks for the feedback. However, on older engines I'm using my own custom PCB.

Bob

[craigz]

Jul 5, 2019 11:42:08 GMT -8 amsnick said:

Hi,

When you want more working outputs or functions the Decoder Buddy will provide 8 outputs that all work well with LEDs. There are, on request 0 ohm resistor boards available that can be used with 14 volt lamps and LEDs with resistors already installed in line. There is also a 750 ohm version for 1.5 volt lamps found in older locomotives. Make your request by email at www.nixtrainz.com they are not available elsewhere at this time.

Nick

Nick, so your board does indeed have the circuitry needed to light the 'logic output only' functions that exist on Loksound decoders?

[amsnick]

Hi Craig, Yes, 8 identical lighting outputs. The logic outputs are converted on the Decoder Buddy.

Nick