Sound board pinout?

[Flare]

I'd like to add a Keep Alive to my Heisler, but I don't know where the blue and black wires should go.

The easiest method of installation looks to be slipping the wires into the sound module plug, but I don't know which pins/holes are +12v and ground...

[dutchbuilder]

Maybe a silly answer, but ever thought of measuring it with a volt meter?

Ton

[Flare]

Nope.  I don't want to risk jumping the wrong pins and ruining it.

[dutchbuilder]

Flare, don't be scared to use a multi meter.They are so designed that you won't blow up your electronics.

Ton

[Flare]

Okay, I bought a multimeter and compared the pinout to the NMRA M21TC connector.

The ground pin is in the same position, but the +12v doesn't seem to be.


Of course after REMOVING the sound board I saw that the back has two through-holes lined with copper marked "+V" and a ground symbol;  Touching the meter's leads to these show I can solder the Keep Alive to them.

Thanks for your help, DB. 

[[email protected]]

Will those connections provide sound and motor stay alive, or just sound stay alive?

Reg Barron

[Flare]

The Keep Alive I ordered should arrive by the end of the week, I'll let you know how it works.

[jkemp]

The Keep Alive I ordered should arrive by the end of the week, I'll let you know how it works.

What keep alive did you purchase?

Somewhat new On30 member here, I would sure appreciate a report back on how your new components did once you have them installed and working for a while.

Thank you,

[Flare]

What keep alive did you purchase?

Somewhat new On30 member here, I would sure appreciate a report back on how your new components did once you have them installed and working for a while.

Thank you,

I ordered the KA3 version;  It seemed to be the best candidate after measuring the available space in the Heisler's bunker with the sound module installed.

I'll gladly post my results if I don't fry the loco in the process.

[Flare]

I installed the Keep Alive using the two soldering points on the sound module, but only the audio is being kept alive.

There is a marked hole on the 21-pin connector that I've confirmed is ground, but I still have no clue which pin is 'positive'.  I've reached out to the service department hoping they can solve the mystery.

[dutchbuilder]

I don't think there is a specific soldering point for +V.
The current comes into the circuit as a sort of alternating current and is rectified by diodes to direct current somewhere in the circuit.
There it is used to run the electronics.
If you do not have any experience with electronic components better ask someone who does because it is hard to explain without the schematics.
Schematics are most of the time hard to come by so someone has to reverse engineer them from the pcb.
.
Ton

[Flare]

The connector seems to be based on this NMRA 21MTC standard which has all the typical decoder wire colors, blue should be in there somewhere:



I've already made something smoke in there trying to find it with my multimeter, so I'm going to wait for a response from Bachmann.

[Hunt]

. . . I'm going to wait for a response from Bachmann.

Some observations –

• The motor decoder with the 21-pins for its add-on sound module does not follow the NMRA Standard 21-pin protocol but is unique SoundTraxx interface for use with the sound module sold by Bachmann.
  
• Your question likely will be ignored by Bach-man and Yardmaster or directed to Bachmann Service Dept. by one of them.  I do not expect Bachmann Service to have the necessary illustrated instructions to add a SoundTraxx Current Keeper or TCS Keep-Alive. While it can be done, it is not easily done as the board is not designed for it.   Advanced soldering skill required.
  
• Hearsay – SoundTraxx is not providing instructions.
  

[Hunt]

Hint –

A SoundTraxx CurrentKeeper or TCS Keep-Alive is not installed by wiring to any of the 21-pins.

[[email protected]]

Agree with Hunt.  A few years ago I was trying to add Stay Alive to the Porter.  My first Call to Soundtraxx resulted in a Polite NO, due to the need to solder to the circuit board.  I persisted and later George B found the correct points from one I of their engineers and sent it to me.  It required soldering the positive onto the center of the tiny circuit board.  The negative point was the same as the neg for the existing tiny sound only cap.  Many times the positive will be the blue light wire, but NOT on the Porter.  If you can find the positive and neg points on the bridge rectifiers, those could work.  Marcus Amman's Main North web page also has a lot of info on adding keep Alives to many decoders, plus some theory!  I never felt the need to add keep alive to my Heisler, since it almost never stalls. 

Reg Barron