Items used:
ZIMO MS500R sound decoder with 8 pin plug
ZIMO STAC01 stay alive (PCB with 3 super-caps)
DCCSound Premium speaker for the Roco F class Kapton and PVC tapes
Disassembly
The body is first removed from the running boards by removing the radiator grille. Once the grille is pulled out from the body, the body itself can be removed off from the chassis/running boards.
Decoder installation
Very little room exists for a decoder, stay-alive and speaker in this model, with a ZIMO MS500R and small stay alive being the only option. Fair skill is required to solder the very fine wires to the decoder and STAC01 stay alive board.
In the example below, the purple wires from the decoder are wired to the speaker. The 8 wires to the 8 pin plug are shortened to an appropriate length then resoldered to the 8 pin plug.
Stay-alive installation
The three super-caps are wired in series with the grey (-ve) and blue (+ve) wires from the STAC01 board. The grey output wire from the STAC01 is wired to the decoder, while the blue/black wire should be wired to the decoder's +ve common wire at the 8 pin plug (when using a STAC01 and not a regular 16V capacitor).
Packaging
Next, the 3 supercaps are positioned under the speaker and both decoder and STAC01 stay alive PCB are positioned on top of the speaker enclosure as shown. Once in place, wrap the side faces of the speaker with black PVC tape. This protects the wires seen below from damage when the body is refitted.
The body is then carefully refitted over the finished chassis. Reassembly is completed by refitting the radiator grille molding.