I've seen locos with a board built in with an 8 pin or the 9 pin plug on them then a separate decoder plugs into that. I cannot find these little boards anywhere. They appear to have some simple surge protection and some resistors for the lights already built in. Seems a good idea to have a board to mount the decoder to instead of wiring the decoder right to the train.

Does anyone know where to get these small boards?

I have a burned out head light on my Baldwin 4-4-0 and I am trying to figure out how to replace the LED. Do I pop the light face out from the front of the lamp? Do I have to disassemble the whole engine? Any done this before?

I actually have two of these, one I got on ebay for like $60 and one I just got new. BOTH exhibited a wobble problem, the new one about 15 minutes out of the box. After some digging I discovered there is a quartering problem. essentially the wheels have spit axles and the wheels on an axle can get turned slightly from running in a tight curve or if the train derailed. This causes a gear binding and a wobble so the train will stutter at slow speeds and make a clicking noise and wobble at high speed.

I found the easy way to fix this is to:
1. Determine which wheel is out of alignment. For me it was the driver wheel connected to the motor (the third from the front). You can determine this by holding the loco in place and turn up throttle till you see the wheel wobble. Or you can do a quarter test by holding the engine in place and run it to get the rods all the way down on one side then look at the other side. The wheel that is not perfectly 90 degrees is probably the one.
2. Unhook tender from loco but do not disconnect wire. There should be enough wire to do the next step. Place the tender on the track.
3. Hold the loco in your palm with the top of the loco in your palm and cab down that way you can see the wheels from the bottom. The tender acts as the pick up so make sure its on the track with both trucks.
4. Turn up the throttle till you get a spoke with a hole to the bottom of the train in the wheel half that is out of alignment.
5. Using a small screwdriver like a jewelers screw driver, push it through the wheel half that is misaligned from the side through the spoke so the blade comes out under the loco between the two wheels. You're effectively going to jam the wheel.
6. Turn up throttle to get the wheels to turn but not too much. Just enough for the screw driver to jam the wheel on one side. You may even feel that wheel slip a bit. Back off the throttle or use a little reverse to alleviate tension.
7. Test train by removing screw driver and see if it runs smooth. If not you will have to do the same thing only run the engine in reverse when jamming the wheel.
8. Keep doing this until the engine runs smooth.

Either that or return the engine to Backmann for a replacement. The stupid split axle design is causing these wheels to misalign.

You can also use a thumb method to adjust the wheels.
1. Again hold the loco upside down on your palm. Use that hand to hold one side of the wheel stiff.
2. Use your other hand and thumb to push the other side of the wheel assembly in the opposite direction into you feel a slight shift.
3. Try train and keep adjusting back and forth till the problem cleans up.