I finally came up with a partial cure. Using POM [programming on main], I set CV 128 to value 0 and this eliminates any sound on DCC startup for this engine. When I want sound, I reprogram CV 128 to any value from 1 to 255. Not ideal, but a way around the problem.

Using F8 to silence F7 before shutting down DCC has no effect when restarting DCC. F7 roars into life. I now have it parked on a siding that is only powered when the turnout activates it, but that is a lousy fix. I now look at the CV options available for programming before buying a Loco. I reprogram all Loco's so that the same F key has the same function on any Loco, regardless of Manufacturer.,i.e.
F3 is Grade Crossing, F9 is Engine Start/Stop. Makes operation so much easier.
I really appreciate all the responses. At least I now know it is a deficiency in the product and not my ignorance in proper procedure.

Thanks Hunt for the fast response.
I agree F8 will turn sound off, but it requires a physical response which occurs after the noise has disturbed the ambience I want when the display is 1st turned. I have MTH, Broadway Limited, and other Loco's that are silent until activated by the MRC Prodigy2 system as I was able to program them via CV commands.
CV 113 Quiet Mode works on some Tsunami diesels, but evidently not on this model.
I still hope someone has a cure, or this Bachmann will go in the closet.

When DCC is powered on, F7A Diesel sound is activated. I want quiet mode until engine is addressed. CV 113 does not work for me.