My totan had the crackly sound, c47 and c51 were still on my board, cut a leg of each out of line, and voila! crackling went away.

It won't fix the between ball pop, that's a software bug. Cutting those caps cleans up crappy audio. MM has a later revision board and it should not even have those caps installed.

Its not a software bug. If it were, every Mm would do it. I own one and have had several through my shop and none do it. Neither does pinmame. The only software contribution is the software does a soft reset of the sound system between balls. But that's not a bug.

Software bug? Hardware bug? Things are often not that clear cut. It could be software writing random audio samples that usually are silent, but on some machines, it comes across as a pop. Sometimes hardware bugs can get fixed with software workarounds and vice versa. The bottom line is that it is unpleasant and removing C47 and C51 does not fix it.

My MM also pops between ball serves no matter how low the volume. Has done this since the day I got it. My sound board has empty spaces for C47 and C51 as Metallik states so the later board revision board does not have those caps. Anyone know if Williams ever released a technical bulletin for this?

I know I am bumping an old topic. Is there a fix for this? Seems like it happens on some machines and not on others? I have an MM loan to me and the popping is pretty loud. Maybe some sort of grounding issue?

I hated that pop when I had my MM. Curious. Does MMR do this?

I'm not convinced that MM original does this short of a few machines with an issue. But MMR has a redesigned sound set up so it wouldn't be hit by this problem

Seems like more than a few machines. Mine did it when I owned one before.

So, if you think it is a few machines "with and issue", what might that issue be? Seems like a charge is building up or maybe a register is not clearing when the sound chip resets?

This game had rev 0.5 game software up until today and I just put in 1.09C. It fixed the phantom lock issues, but not the sound. The sound rev shows as 1.0 and I am pretty sure that is the latest sound revision.