Thank you for your responses!  It also seemed strange to me that the ROM would affect the sound, so I haven't ruled out the possibility that it is a coincidence.  Please see the attached photos.  I can post others if I missed a relevant part of the board.

(Let me just admit up front that my soldering skills are amateurish at best...)

Also, one more thing, the sound works great through the headphone jack--loud and clear.  I have tried the board in a different SE/30 (that has a speaker I know works), so I'm pretty sure there is no issue with the speaker.  I has to be an component on the board.

Thanks again.