Try the State Sheriff's Net channel on 155.730. It goes by Channel 12 on County PD radios.
That's where I've been hearing them with the normal amount of traffic the past couple days or so. Also using a PL tone of 85.4 currently.
Sometimes the precincts will also pop up on one of the Riot channels when they have communication issues. Riot A seems to be popular for Muni-West when they have radio issues and Sheriff's Net for 4th Precinct seems pretty common.
I also heard what sounded like a fast clock tick running for several minutes at a time across all the counties listed VHF channels the other day, one channel at a time. Even the ones used by County Parks Maint, Admin and Ranger channels. The clock tick rotated through all the Riot channels as well.
I never heard dispatch or radio repair come on and advise the mobiles to switch to another channel when the odd ticking was going on even though it did appear to be some form of planned test judging by the way it rotated through each channel one at a time.