Class 73 electro-diesel sound decoder and speaker (21 Pin)

This decoder has been designed so that you can run your model in diesel mode and also, with limited capability, in 3rd rail electric mode; all of our sound recordings for this decoder are courtesy of GBRF who supplied the loco!
To run it as a diesel F1 start/ stops the sound as normal and the loco runs conventionally with all the normal functions and random compressor sounds.
To run it as an electric, when stationary press F1 to switch off the engine, just as the ‘chhhh’ noise is heard press F7, the fan noise will then start up and continue until you press it again, the loco can now be run as it would on 3rd rail pickup. The operator can switch the fan on and off whilst controlling the locos speed. The fan noise can be started when the loco is in acceleration and picking up current, then switching off as it decelerates as per the prototype.
The random compressor noise will not work in 3rd rail pickup mode as it needs F1 to be on, so F5 allows the operator to run the compressor, again it is latched and will continue until F5 is pressed again.
Unfortunately pressing F1 whilst in motion will not start or stop the engine on the ‘fly’ as can be done on the prototype, it will cut straight in or out as if the engine was on full throttle, this is due to the nature of the decoder sound files structure. A smooth switchover has to be done whilst the loco is stationary, the decoder is not designed to provide sound operation for a dual operating system such as is the 73.
When running the 73 in electric mode the Function keys for the horns, compressor, flange squeal, guards whistle short and long and flash sounds from the pickup shoe can all be played. The flash settings are linked in the sound file to Aux 1 so if a blue LED is fitted to the pickup shoe and wired to the aux 1 wire from the decoder it will flicker when the F10 and 11 buttons are operated.