Am using several SN74221 circuits to generate timing waveforms and triggering three of them from the same input pulse. One operates normally but the other ones ignore every other pulse (output is half the rep-rate of the 100 Hz input pulse string). Any ideas what is going on here and what I can do to resolve this? Pulse widths being generated are in the range of ~3 to 200 us. Logic supplies and all else seems ok as far as I can tell.
