In theory, all work is done with the tender.
The tender is disassembled through four screws holding the frame to the jacket.
The following items were then fitted to the tender:
ESU (58420) LokSound V5 DCC 8 pin decoder with S class sound,
Stay alive (1000 uF), not pictured
DCCSound Premium sugarcube twin driver speaker (4 ohm)
The 8 pin plug is removed (DC operation), and the decoder with pre-attached stay-alive is plugged in to the 8 pin socket.
The speaker is then fitted in the tender using double sided tape. In this case the oil tank extends down into the tender space, so the factory fitted weight needs to be relocated towards the rear of the tender to make space for the speaker.
All electrical contacts are protected from possible short circuit with the metal model using Kapton tape.
Finally, the tender was reassembled and tested with the engine.
A short circuit was identified due to the metal brake shoe rigging, so in this example it was removed via two screws on the underside of the engine's chassis.