Thanks Lee, I will pull the shell off and take a look.  Now for the strange part . I tried the horn and bell last night again and now they both are loud.  Maybe a loose wire to the speaker ??

 Hello, Im new to Williams trains and O scale in general . Have always be molding HO scale.  I picked up a Williams SD 45 w/ the TB II sound unit at the Greenburg show this past weekend.  When I got home and tried the unit she runs fine forward and reverse. The horn and bell work but they start out low and go softer as the sound board is on ............Is this normal ??  I'm running this on MTH Realtrax with the 100 watt Z transformer
Ohh and not matter how high or low I set the throttle is stays the same.   It is so low that when the trains is moving the clack of the wheels on the track drowned it out...........Would this be a service issue ??   Thanks for any help you can offer..........