It may happened early morning this mornng (4/26 3:00JST)
At this timing, no mine work, no excitation would be expected.
I kept this machine this situation.
It doesn't seem to a same problem as past issues.
It seems just a electrical glitch around timing signal.
I think a cabling and electrical connection around MCF0 is better to be reviewed.
Otherwise, I have a feeling the problem will repeat.
-----
In this time, only slave model was dead by losing timing synchronization of ADC. On the other hand, IOP model was still running. So it's not a problem on HIB cards. Similar issues sometimes occurred when we worked around field rack. In this time this issue occurred in mid night. So it shouldn't be related to human activities in the mine. I'm now doubting that MCF0 rack is affected by some instruments because this rack is connected to the power source of wall (? precisely speaking in the clean booth) electrical outlet. Of course there are some racks witch is still connected to the wall outlet. But AC instruments in these rack is not floated from AC GND. A number of instruments in MCF0 rack is quite smaller than other racks. It may be also a reason why MCF0 rack is easily affected by the outside of the rack.
I turned off the speaker/shaker amplifiers and disconnected their power cables.
