Heljan O Gauge Class 73

Kit: MS990L; YLR302815; RE Slim Boom Box 50x15x15

Voted one of the top models of 2024, Heljan's O gauge Class 73 is covered in detail, and looks especially good in Pullman livery. It comes with an 'XL' socket for easy DCC sound conversion.

There is even a mounting for an ESU smoke generator, though we found this was not particularly practical because it is not close enough to the outlet in the roof!

The XL socket is great, except that ESU's XL standard is slightly different from the Zimo standard (the servo connections are different). The model doesn't have any servos though, so we can make it compatible by simply removing the header pins for servos. Lift off the plastic socket from the appropriate side and snip the unwanted pins flush. Then our Zimo MS990L should fit in more easily.

We decide to go with a pair of speakers, which fit snuggly inside the body... a YLR302815 2W traditional box, and a Rail Exclusive Slim Boom Box (50x15x15mm). This combination seems to work very well and gives lots of volume as well as a great frequency range.

A modified version of our Class 73 project gives control of the various lighting features, as well as syncrhonisation of the arc-sparking white LEDs in the bogies, which will briefly flash whenever the random arcing sound is played (only in motion of course).

A few more pictures below of the modifications to the MS990L decoder and positions of speakers with a different model...

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.