Bachmann K27 Titan large scale decoder no so

[krinor62]

Hello,

In the mean time I tried my Bachmann K-27 with my new Digitrax DCC system. I can get the locomotive to run in DCC; I can turn the various lights on and off and I can program CVs. So the decoder works in principle. However, I do not get any sound. I installed a 3'' speaker from Soundtraxx. I cheked the voltage when the locomotive is on. I cannot detect any voltage on the Pins which lead to the speaker. So I do not think that the speaker is the problem. I also tried to program the CVs which turn the sound on and off at start up as described in the manual. The programming seems to work but it has no effect on the sound. Has anyone had a similar problem? I am not sure if I missed anything or if the decoder has a problem.

Best regards

Krinor

[Kevin Strong]

I don't believe the Titan uses the pins to send sound to the speaker; you've got to wire the speaker directly to the screw terminals. The older "Quantum" boards had a 2-pin socket on the board itself to connect the speaker, so on the K-27 I've got in the workshop with the older Quantum installed, the speaker connects to that socket. It didn't use the pins, either. On the Titan, it's J2, pins 1 and 3 (front speaker) and pins 4 and 5 (rear speaker). Try wiring the speaker to one or the other of those screw terminals. It doesn't matter which, really. By default, all the sounds are balanced equally between the two speakers.

That's how I've got the Titan in my Climax wired.

Know also that if you want to use the optical chuff circuits to trigger the chuffs, you'll have to invert the signal coming from the chuff circuit on the board to do so. There's instructions on how to do this elsewhere on Bachmann's web site, under DCC references. Otherwise, you can use the BEMF-controlled chuff of the Titan. I've not had consistent luck with that with the older Quantums on the K-27s, but I'm told it's improved on the new Titan boards. I've not had opportunity to try that combination yet.

Later,

K

[krinor62]

Hello Kevin,

Thank you for your reply. My Titan board has the socket for the speaker, too. That's what I used to connect the speaker. I will try directly wiring the speaker to the screw terminal.

Thanks

Jan

[krinor62]

Eureka, we got sound

Kevin, your tip to directly connect the speaker helped me solve the problem! When I connected the speakers directly, I got full sound. So I checked the original wiring provided in the tender of the locomotive. The culprit was one of the connections I had soldiered to the speaker. It looked good (that is why it did not occur to me that the connection was bad) but was not connecting properly. Applying a little more tin solved the problem.

I am absolutely happy that everything is now working as expected even if I had to spent a whole day trying to solve the problem by programming the decoder. Stupid ey? At least I am now comfortable with programming.  

Now with sound programming is even easier as you can turn on the "talk back" feature. The decoder repeats the value of the CV you programmed which helps to avoid mistakes.

Thanks again to the Bachmann forum. You guys are really great!