The circuit board was developed for the Märklin locomotives of the BR 34 series and fits exactly in place of the original decoder.
For decoders with 21MTC interface.

For the current-carrying coupling of the locomotive, a solid-state relay is installed on the circuit board, which switches on the traction current to the coupling by means of function output Aux1 for the carriages.

Despite the limited space, this adapter is also suitable for sound decoders.

The connections Aux2 to Aux5 are led out directly from the 21MTC interface on pads. The function of these connections depends on the decoder used.

The strands of the loco are soldered on as shown in the description.

Space for a speaker is available in the loco for flat speakers up to about 6mm thickness above the decoder under the coal imitation.
Use double-sided mounting tape to attach a speaker.

Supplied without decoder and without bulb. Use the locomotive's existing bulb.

Operating Manual 8048