This problem now occurs VERY rarely: Performance seems ok except that channels 3 and 4 intermittently drop out, with recorded data consisting solely of -1 (1-bit recording). There are no indications of this error state in the LEDs of the front panel. NOTE: as of 4 Nov 2010, not always channels 3 and 4. This time channels 1, 9, 11 and 12 dropped out:
![Autocorrelation plot Autocorrelation plot](/opswiki/lib/exe/fetch.php?media=hardware:before.png)
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On another occasion channels 1, 2, 9 and 11 dropped out while channels 12 and 14 looked strange: