Does it work with headphones? If so, the connection from the mini jack to the audio source is incorrect or has no pre amp. If not then you have a setting wrong. What internal source are you using on your CS3? Locomotives have speakers. If you've downloaded sound files, they may not be correct also. I haven't tried to.

Hi plujan
The CS3 user's manual about the stereo loudpeaker plug to connect an extern active louspeaker
It means there must be an external amplifier to drive the loudspeaker. Alternately, hearphones can be used
The volume can be adjusted in the folder CS3/Parameters
See lower-center part of screen in red frame

Cheers
Jean

I connected an external amplified speaker to my CS3 and it worked. Not sure if you are following the procedure but you need to create an event with a sound from the internal sound group. I was able to make all the internal sounds play through the external speaker Did not try to make my own sound nor load a new sound. Are you using a stereo mini mike to connect to the CS3?
To summarize: the CS3 external sound output looks like a female RCA plug but is a female mini stereo microphone plug. I think, though am not certain, that plugging the proper plug into it shuts off the internal speaker. If that is so the fact that you are hearing the internal speaker with something plugged into the output suggests to me that you have the wrong plug. But I would need to confirm that. I am fairly certain that to play any sound you need to create an event with the sound in it or at least access the sound file through the event feature. I think, if i remember correctly, that once I created an even I could then cause the sound file to play simply by clicking on it. There was no need to run the event.

Edited by user 30 January 2023 19:59:16(UTC)  | Reason: Not specified