When I last ran my LGB 20273 LD1 the fan in the smoke unit began screeching quite loudly. I had to replace the unit once already due to a failed bushing on the fan motor. Today, I opened up the smoke unit to put a dab of oil on the motor bushing hoping to save the unit before the bushing destroyed itself. Removing the leading truck gives access to one screw keeping the loco smokebox in place. The front steam dome has a pin that retains the top of the smokebox. Taking the top off the dome gives access to a screw holding the dome to the boiler. The smoke stack also needs to be taken off to remove the smokebox. Give it a 1/4 turn counter-clockwise to align keys molded on the stack to the keyways on the smokebox then pull it straight up. The smokebox can be worked free once the stack, bottom screw and dome are taken off.
After the two tubes feeding "smoke" to the cylinders are disconnected from the smoke unit it can be wiggled out of the boiler. There is plenty of slack in the wires between the smoke unit and the decoder to allow it to be pulled out far enough to work on. The following few pics are of the old, failed unit but do illustrate what I did to get to the fan motor.
First the fan had to be removed from the motor shaft. It pulls straight off. I used needle nose pliers to get it off. The circuit board to which the fan motor is soldered can not be taken out of the smoke unit housing unless the fan is off.
Removing the four screws on the top of the housing allows it to be opened up -
and the circuit board can be taken out.
This shows the motor shaft bushing that failed on this unit. That is where I put a small drop of oil on the one I serviced in the LD1. Unfortunately the bushing on the other side cannot be gotten at without desoldering the motor which I was unwilling to do. After reassembling the smoke unit housing I added another small drop of oil where the fan motor shaft comes through the housing before pushing the fan back on the shaft.
Here the unit is being tested before reassembling the loco. I also replaced all the plastic tubes feeding "smoke" to the cylinders. The tubes become quite hard after being used and are best replaced. The second pic below shows some smoke unit tubing I got from
Schlauchset für Gepulste Verdampfer 4 Stück ML-Train 86101004 when I last ordered parts from them.
The screeching is now gone so hopefully this took care of the problem. I should note that a whole lot more loco disassembly is needed to replace the smoke unit as access to the decoder is needed.
Edited to note that the smokestack must also be taken off in order to remove the loco smokebox.
Second edit added: I'll make sure the oil the motor on the next replacement before I install it!