Let's fit a Zimo MX645 sound decoder to this Bachmann OO Standard 4MT Tank... take the body off the chassis by removing the 4 retaining screws... 1 at each end
plus 1 each side half way along the chassis:
This model came factory-fitted with an 8pin Bachmann decoder, which we'll unplug.
In order to fit in a sugar-cube speaker and the MX645 decoder, we need to remove the 8pin DCC socket and mounting points:
The speaker then sits flush where there socket was. In this example I've used a 12mm high Zimo sugar-cube. The MX645 goes into the same place that the
original Bachmann decoder was, with any unused wires trimmed a little and stuck neatly out of the way. Zimo provide purple wires for the speaker connection.
I've also left the blue and green wires available, as I shall add a firebox glow light to this model (not detailed here):
All back together, and tested - a very quick and simple installation!
All disassembled and with the MX649 hard-wired and SugarCube9 in place in the boiler.
Perhaps the toughest part of this install is cracking off the bunker... it was really wedged on with this example and needed a lot of persuasion to
come off, but once done, we have easy access to the cab to add crew, firebox glow, and route a pair of wires through to the bunker for our stay-alive.
We add longer wires for the stay-aive / SPEIKOMP kit, which are blue and grey from the decoder (blue is the existing common positive blue wire and grey
is a new wire soldered to the GND pad of the decoder (not to be confused with the grey motor wire!) We also have the blue (via a resistor for the firebox
glow LED and orange for the firebox glow negative (connected to the decoder's green AUX3/FA1 output).
Just the stay-alive blue and grey wires come through the cab, filing a notch in the bunker wall so they can come right inside the bunker when
The SPEIKOMP kit is assembled, and a 1000uF electrolytic capacitor is hooked up.These fit easily inside the bunker space.
Bunker screwed back in place, and chassis screwed down, final touch is to just add some lump coal.