Thanks to everyone for their inputs.  Very enlightening!

As to my original issues, I intend to discard the printed circuit board and install the decoder per the standard decoder installation requirements.  This is easier than trying to decipher the circuit board, and also allows more flexibility in the mounting of the decoder.

Happy railroading!

The SD-45 (DCC ready) was tested on DC and everything worked fine: motor, direction and lights.

I then installed a NCE D13SRP decoder in the engine.  After removing the jumper board, the decoder's NMRA plug was installed per the marking on the engine's circuit board.  The following was observed: the engine ran but it's direction of travel was long-hood forward (reverse of what it should be) and neither LED would light.  I reversed the NMRA connector and the engine ran properly (short-hood forward) but again neither LED would light.  The decoder was removed and the jumper board was reinstalled and again everything functioned normally.

From reading other literature, it seems this engine has capacitors and inductors that are used to prevent radio noise when operated on DC power, and these are required to be removed for proper DCC operation.   There are 2 inductors (L1 & L2) and 4 capacitors (C1, C3, C4 & C5).

L1, L2, C4 & C5 appear to be in the motor circuit and C1 & C3 may be related to the LED's circuitry.

Questions:
Are all components listed above to be removed?  If not, which ones?
Are any additionl component changes required to get the LED's to work properly?

Thanks for your inputs.

Here is how it's done:

The body shell is held in place by the two coupler boxes.
1. Remove both coupler assemblies from the engine by removing the mounting screws, then pulling out the coupler and box.
2. Disengage the alternator (simulated) plastic wire from one of the lead trucks by gently prying it loose from the truck.
3. Carefully pry the body shell away (upward) from the chassis keeping an eye on the alternator wire so it does not snag.

That's it!

I recently acquired a Spectrum SD-45 (Item No. 82706).  How can the body shell be removed?  I removed the fuel tank cover and two screws were revealed, but it does not seem that these have anything to do with retaining the shell.  The details on this locomotive are quite fragile and I do not want to damage them out of ignorance.  Your help is appreciated!