These sound boards are now available again at reasonable prices on Ebay following a period of absence.
I`ve just finished installing one in an Aristo Vanderbilt tender. The example in the foreground is for another future installation.
I chose to make a few minor modifications to make the installation neater. The operation rod of the volume control was removed and reinserted on the opposite side after opening out the hole in the circuit board a little. The flickering firebox moulding and leds were removed as was the board with the storage capacitors. As this is an analogue installation the capacitors were still needed (for digital I`m pretty sure they are switched out with DIP switch 1) they was mounted away from the main board and wires run between the original connections.
I thought it may be useful for others to be aware that the board may be successfully modified in this manner. I thought I had blown it up for a while, it turned out that I had inadvertently pressed the two bare leads of the diode and resistor near the input together causing a short. Normal operation was restored as soon as they were separated, the two offending components are shown in the close up.
The loco driving wheels are significantly larger than the tender wheels, luckily the ratio is very close to 4:3. Six magnets, with alternating polarities, on the tender wheels give two chuffs per revolution of the loco drivers.
To clarify a South pole turns the Hall sensor on and a North, off. The sound board is configured to ignore every other input signal to give two chuffs per revolution of a standard axle mounted LGB ring magnet.