The Z80 error is when the sound CPu no longer responds. Several chips can cause this.
z80
6116 sound RAM
SM1 sound ROM
Neo-B0
For some reason, the YM2610 has NEVER caused a Z80 error in all my years...
(as a hint, if you have no sound, check the /IRQ line on the YM2610. If its staying low, the YM2610 is bad....)