I've seen SWE1 sound ROMs in the ROM board in backwards. Be sure
they're in correctly with no bent pins.
Be sure you're properly doing the update to the PRISM after the ROM
swap. No sound is one of the symptoms of no update to the PRISM being
done after swapping ROMs.
--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
314-766-4587