<p>is D7 in the right way? It should be pointing down. You said that the lights are blinking and the dividers are doing what they are supposed to do?<br />
Are you sure that the input jack ground lug (the one closest to the edge of the board) is connected?</p>
<p>It's more likely that the problem has to do with the pulse width of your input clock.<br />
The tremolo circuit has an attack and decay time. If the pulse is too short, there isn't enough time for the attack to reach it's peak... so you don't hear any sound.<br />
Try connecting the trig in of the Drone Lab to a square wave LFO that you know has a 50% duty cycle ("square" not "pulse").
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