I know this topic is of interest to a number of people, since there were a lot of comments regarding not being able to open up this model for servicing. So I will attach photos, show you what I saw/did, and then comment and ask questions about the wiring.
Member Chris was right, his method for opening the roof worked like a charm You need to push down slightly on the ladder rungs on top of the roof to slightly bend the ladder, and then use a flat head eye class screw driver or small from the bottom of the frame (you cannot do this the sides, for sure), and then insert the flat between the frame and the lowest ladder rung and gently pry-the ladder rails will quickly pop out of their mounting holes with no resistance. Once you do that, you can remove the four deep set screws which attach to the roof from the bottom of the frame, and the roof will come off without effort.
The chimney flue is mounted on a horizontal plate, which you can just lift out of the way. The seating and orientation of this plate is intuitive.
The wiring looking a little tricky than what I thought I would find, and would appreciate some thoughts. There are eight incandescent bulbs on a board, which is screwed to the roof. As of this writing, I don't even know how many of those are still illuminating, but am going to find out. It does not look it is so easy to just cut the leads and solder in new LED's. As it looks the marker lights are depending on that board wiring. From what I can see from the marker lights, mine work-but there would be no changing them. There is no bulb there, inserted into a shell or lens. It looks like the molded marker light is itself the bulb. There is just wiring going through a hole in the car body to the marker light on the other side.
Secondly, the marker lights seem to get their power from two copper contact strips, wired into the the light board, which then make contact with two grommets on each side (each pair of grommets must be for positive and negative terminals, I guess) I have noticed that both the grommets and the contact strips have a lot dirt/crud on them. So if I clean them, that may improve things, as far as the marker lights are concerned.
So that leaves, what to do about the incandescent bulbs? If I cut the leads, then the marker lights are not going to work, anymore. If I try soldering the LED's to the copper contract strips, then I am going to end up still with flickering incandescent lights and steady LED lights.
Does anyone think I can get away with cutting and removing the light board, and using WAGO connectors connect new wiring for the LED's and maintain also the connection for the markers? Ended up being a bit more of a project than I thought, but maybe it will work out.
