Bachmann Green Deltic
receives an EM2 speaker
Another loco aimed mainly at our extended "Little Histon" layout, to enable diverted ECML trains to make an occasional appearance in the early 1960s time period.
Bachmann photo of D9001
I'm going to try to install one of Bif & Charlie's big EM2 high bass speakers within the fuel tank area. This will be driven by an ESU LokSound V4 with Bif's latest Deltic sound project on board. Its going to be a close fit, but with the removal of a small part of the chassis assembly, I think it can be done.
I'll also make some minor changes to the lights to enable independent control of the running lights at each end (headcode displays and rear lights) and I'll disable the empty cab lighting.
I'll fit appropriate stay alive capacitance, consistent with the available space, if required.
The locomotive runs smoothly in DC configuration, straight out of the box. So I don't anticipate any running problems when under DCC decoder control.
Decoder CV Adjustments:
Just some adjustment of CV133 so I can fade up the engine sounds as the motors come out of idle. Some adjustment to the function mapping to run the front directional lights only on F0 while the rear directional lights are switched using F11. Bif's defaults left elsewhere.
|F0||Directional rear & head code box Lights on Driver's end (H/L fwd; Aux1 rev)|
|F2||Horn high note (playable)|
|F3||Horn low note (playable)|
|F6||Drivers sliding door open/close|
|F9||Wheel Flange squeal|
|F11||Directional rear & head code box Lights on rear end (Aux2 fwd: R/L rev)|
|F16||Fade sound level by 50%|
|F18||Detonators (also Aux 3 synchronised flash)|
|F19||Driver's cab light (Aux4)|
Fitting the EM2 speaker (Its big!):
Not a job for the faint hearted! The only viable location I could see, without hitting the motor, was in the fuel tank zone immediately below the motor.
I removed a few small sections of the chassis block with a junior hacksaw and cut away the motor suppressor caps, to enable the rear of the speaker to sit touching the motor underside. This required an EM2 length of fuel tank to be carefully cut away.
There is a diagonal piece of circuit board fixed to the rear of the speaker. After removing the wiring plug from the side, new speaker wires were soldered to the equivalent track pads on this board.
The speaker was orientated to place the pcb away from the metal motor body to avoid shorts. A slim piece of plasticard was then used to provide a barrier between the flywheel above and the exposed speaker pcb tracks.
In an ideal world, I would have used the previously removed fuel tank sides, glued to the exposed sides of the EM2. However, this would have required removal of the inside 2mm of excess plastic from the moulding and I couldn't think of a realistic way to achieve this in a finite time. So instead, I scratch built less detailed side pieces from plasticard and glued these in place to help camouflage the speaker. Finishing with filler and a new weathered paint job for the fuel tank sides.
EM2 facing the tracks
The driver's end head code and rear lights will be driven via FO H/L & Aux1 respectively.
The other end head code and rear lights will be driven via FO R/L & Aux2 respectively.
Driver's cab light will be driven by Aux4 via a 2N7002 MOSFET buffer.
A detonator flash LED (if fitted) will be driven by Aux3 via a 2N7002 MOSFET buffer.
The Aux 3 detonator flash LED and MOSFET driver will be a possible addition later.
The completed Deltic:
Driver's cab light on. (this shuts off automatically when the loco begins to move.)
Hauling a mix of Hornby and Bachmann maroon Mark Ones.
Please click here to see (and hear) a You Tube video of the Deltic in action
Adding stay-alive capacitors:
While recording the video sequences, I came across a tiny gap in the audio produced from the decoder. Not sure what provoked the issue, but some stay-alive capacitance should prevent a repeat occurrence. However, there is not as much headroom above the chassis block as I expected, due to the fans installed below the roof vents. Still plenty of space for a Zimo SC68 supercap. 6800uF should bridge the kind of gap causing concern OK. The new part has a higher voltage rating than equivalent parts I've used before (16 Volts rather than the original 15 Volts,) However, reading the Zimo text, they indicate that a maximum DCC track supply of 16 Volts can be used. Now a 16 volts peak to peak DCC waveform will translate into something much closer to 15 Volts across the capacitor. So I will fit a protection circuit that maintains a maximum charging voltage of less than 15 Volts as before, just to be safe.
Some possible cosmetic changes: