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TT064B is an almost-identical copy for the Doyle group. The only difference is that the input threshold range is changed from (+/-1V) to (0 to -1V).
No, TT064B changed the input to a PulseShaper
Comparator thresholds are adjustable from -1V to +1V with the blue trimpots. You can monitor the threshold by putting a voltmeter on one of the MON pins. You can see white lines connecting the MON pins to their respective input channels. For the voltmeter's ground, use pretty much any exposed metal – BNC shields, screw holes, etc.
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