Can anyone identify for me where each wire from the circuit board in the tender ultimately goes to (eg. headlight, motor ...)?  Thanks.

How do I remove the smokebox front of the Spectrum 2-10-2 to replace the headlight bulb/LED?  If I have to remove the boiler to do that, how do I remove the boiler? 

I want to install an MRC DC sound decoder in my Spectrum 2-10-2.  Do I just unplug the DCC decoder in the tender and plug in the sound decoder in its place?  I operate on analog DC.