The Di3.643 was built in 1958 and was a NOHAB demo for the Finnish railways. It was bought by the NSB in 1960. It has seen all the various liveries, green, gammel design, mellom design and ny design. In late 1986 during a revision the nose lights were removed. Then in 1991 cab 1 was isolated and it got the new panser glass in cab 1. The glass has the newer frame around it.

As the late 1980's is my favorite era I was very interested in getting a model of the Di3.643 in ny design without the nose light. I already have a 1990's model of the Di3.643, as that was provided by Bergen Modelljernbane based on a Heljan model.

A good starting point for a Di3.643 is the Heljan model again, as that is a model of the long Di3 (the 602, 622, 623 and 641-643 were longer than the other models). I was able to get a model of the original Heljan/BMJ Di3.621 and thas was the starting point of this project.

The project started with removing all the detail parts from the shell. To remove the nose light I masked the nose, to avoid scratching or damaging the rest of the nose/shell.

The hole in the nose is then filled with Tamyia putty and then sanded. This had to be repeated a few times to get a smooth surface. The old 621 numbers were than removed. The nose area was then air brushed with a closely matching red color. After some experiments I found that Modelflex SF red is pretty close. Decals were applied to get it renumbered to the Di3.643. To get a nice even finish across the whole model a new top coast was applied using Tamiya TS-80.

The Heljan models are known for having poor wheel conductivity and therefore a power pack is a must in these locomotives. The ESU power pack is installed in the diesel tank under the frame. A small whole is drilled in the frame for the wires. To do this the motor has to be taken out.
The original PCB is not going to be used, a Nixtrainz decoder buddy is used instead. This board is much smaller than the original PCB. The main reasons for using the decoder buddy are: built-in resistors for LED lights and connections for the 3-wire power pack. I installed two ESU sugar cube speakers.

6 LEDs are used for lights. The top-light is made with a separate SMD led. Cab lights are made by glueing a small LED to the back of the interior cab insert. Then all the wires are hooked up to the decoder buddy connector. This allows for removing the shell in the future. All the various outputs are clearly marked on the connector board which makes for an easy hookup.

The end-result. A NSB Di3.643 in ny design, as it ran from late 1986 until early 1991.