putting sound decoder in spectrum j class

[ewing railroad]

i bought a sound decoder with speaker for my spectrum ho n&w 4-8-4 j class,plugged it in,train runs,but no lights front or back,do they have to be changed due to voltage increase on dcc?i am using a mrc prodigy express,also what is the best way to mount the speaker,tender has place for it,but how to secure speaker with best sound quality?any help is appreciated.one more question,how do i  mount the extra circuit board?secure it to the tender weight somehow?

[Doneldon]

ewing-

You can glue your speaker or mount it with screws. If you use screws, include a thin gasket to ensure a good
sonic seal. Rubber gasket material or even cardboard will usually work. How you mount the extra PCB is a
function of where you mount it. Since it's just sound (no motion) the tender would be a reasonable location.
Mount it there with double stick foam tape. (You can use that for mounting the speaker, too. Just cut it to
shape.)
                  -- D

[ewing railroad]

thanks for reply,sounds like good advice,what about the lights?they worked fine before in DC,did the switch to DCC fry them?changing the tender light won't be too bad,but very little room in the engine!any suggestions? Jim

[HDiedrichs]

I upgraded two Richmond spectrum 4-4-0s to Tsunami sound controllers. For the lights, if they are LED they are probably 2-3 volt LED and the output of the controller is probably 12 volts so if you wired it up directly, yeah you most likely fried the LED. You can test the LEDs by taking a 9 volt battery and a 1k ohm resistor and connect the cathode to ground and the anode to the resistor then to positive. Here's an example and how to calc the resistor.

http://www.instructables.com/id/LEDs-for-Beginners/step6/One-LED-with-a-resistor/

If the LED lights with a battery then you wired it wrong. I found that on my tsunami controller the so called positive lead for the head light was actually negative and the common negative actually was positive so I had to flip them (or the LEDs had flipped anode and cathode). So you can check that as well.

Get a volt meter to see the output of the controller chip. If its higher than the volt of the LED then you have to drop it down with a resistor. If its a lamp then the lamp is probably fine. The tsunami controller had an output of 12 volts to the head lamp and tail lamp and the LED was around 2 volts so thats a (12-2)/10ma = 1k ohm resistor. A 1k ohm resistor is usually a good general resistor to use.

So to diagnose see if the light can light up with a battery and resistor. If so then see what volt output is for controller and note which is positive from the controller and for the LED. Then connect lamp with 1k ohm resistor in series along the positive.