Here is a simple conversion suggestion for the old LGB-2×430 locomotives (Ge 4/4-II) without interface.
With an additional 24V relay you can simply use the old pantograph control.
The three-pole cable from the lower part to the upper part is removed.
The electronics (motor control) in the lower part are replaced by the XL / XLS decoder.
The white + brown cable is connected to the decoder via the relay as in the sketch. The green cable remains unused (isolate).
As soon as the light function is switched on at the locomotive, light and pantographs automatically change the direction.
Instead of the light output you can also use any F output and control the pantographs manually by button.
Due to customer suggestions a few additional notes.
1) If you want to change the locomotive even less, you can leave the lower board also in the locomotive.
The two 3-pin cables are then removed from the gearbox and the decoder is connected directly to the gearboxes.
The one “old” gearbox cable is completely isolated, the second one is connected as described above with the decoder (green isolate, white and brown according to the switch sketch.
2) Wenn man die Funktion auch digtial an- und auschalten möchte, kann man den Anschluss “Dek-” durch einen schaltbaren Ausgang ersetzen (z.B. Licht Innen oder F1).
Attention: This output must supply at least 0.6A current.
3) If the light + pantograph is switched incorrectly, the white + brown cable must be replaced at the relay.