Kit: Zimo MX644D with Zimo YouChoos Flame10 speaker, independent cab lights, crew, SuperCap6800uf stay-alive
So many versions of the Bachmann 37 are available... this one is a fairly simple 21pin modern version...
Despite providing a dedicated space for a speaker, the flat 20x40 one suggested doesn't give great performance, so we're going for some
minor modifications to accomodate a YouChoos Flame10 instead.
Here we see both the Flame10 and the suggested flat speaker side-by-side. We want to retain the roof fan, so chop off one end of the plastic mount
where the Flame will sit beneath. It will be a tight fit, but will go.
Grind down the small ridge in the inset area so that the speaker can sit flat.
Next add the driver at the rear end (model comes with one driver at the front end already).
For independent control of the cab lights, we need to rewire the rear cab light to FA3/AUX4 of the decoder - solder wires directly to the 21pin
plug. The front cab light is already on its own control (FA2/AUX3), so nothing to change there. Don't forget that a resistor is required on the
positive wire to the rear cab light, as we have now bypassed the model's circuit board for this LED.
Tried to fit an inexpensive 1000uF electrolytic capacitor as stay-alive, but it just won't squeeze in under the fan, so switch up to a
SuperCap6800uF instead, which lays flatter, and gives excellent backup power.
Tidy up...note the electrical tape over the cab light controls at the rear end, as we have wired directly instead.