Unless it is a Soundtraxx decoder, any other Bachmann with DCC on board are hit or miss. The first thing I do is take out the chokes on the circuit board and solder wires in their place, next I take out the capasitors, Then I replace the decoder. The first thing you will notice after that is all the buzzing and humming goes away, the slow speed is 90% better and you will be a lot happier. "Thats just how I fix it". Bachmann makes nice trains but I am not a big fan of how they do their DCC on board stuff. I know when I buy a DCC on board loco is I have work to do. but I like doing that kind of stuff. I am tinkering with a Bachmann 2-10-0 decapod now.
Truck.
You do not have to remove the inductors. With the capacitors removedby just clipping them off, the inductors are a moot point. I and many others had to only remove the capacitors.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
What looks like resistor are inductors. Notice the L! and L2 labels. The capacitors will be labeled with a C and the resistors are labeled with a R.
A PC board in my 44 ton, the inductor is actually a wire wound device. You can see the wire coils.
The ones you see on yours are ferrite type inductors.
The capacitors are sometimes yellow, The surface mount capacitors are quite tiny. Look for the C. Might be C1 and C2. I snip them of with a small pair of wire cutters.
The decoder installation shown in this link is a bit out of date, and it's for a different loco, but it does show clearly where the capacitors are that need to be clipped.
http://www.gatewaynmra.org/dcc/engines/bach-280.htm
Note too that the Bachmann 4-8-4 is not part of their "Spectrum" line but is in their lower-level line, so may not be as well built (or run as well) as a Spectrum engine no matter what. However, clipping the capacitors and adding a good decoder (preferably one with Back EMF - I prefer TCS ones as their instructions for setting the CV's are so clear) will make an improvement.