671:  there are two cards (circuit cards, taped together with wires in between.  Not sure how to ID the sound card. 

Took cover off; the speaker is connected with a one red & one black wire coming from the circuit board.  Looks like I can easily remove the speaker from base (2 screws) but the I will need to cut the speaker free (ie cut the red & black wire).  Do not see any way to remove wires from circuit board.  After cutting & removing speaker, just leave the wires loose inside?  Any thoughts that the circuit board will heat up with a continuous sounds being sent (but not heard)?  thanks for the help

WILLIAMS RIO GRANDE LOCOMOTIVE #5720 sound activates about 10 seconds on its own & then stays on making a loud/ugly sound.  Only turns off when I hit the Bell on the transformer.  If I hit the Bell button every 7 or so seconds the Ugly sound does not come on.  No switch for turning off sound.  Can you remove the sound card or is there something inside the unit that you can adjust to turn off the sound ??