[Test-Equipment] Curve Tracer Problem

[k0xp at k0xp.com]

I built the curve tracer designed by WB9LVI and presented in the July, 2006 QST and July/August, 2006 QEX. I've corresponded with WB9LVI about a problem I'm having but we haven't found a solution.

I can calibrate, so the hardware is working, and the software is at least listening to the sound card. But the sound card isn't generating the few cycles of 240 Hz that generate the I-V plot.

I've tried two different sound cards with the same results: A CT4870, and a CT4830. Both work fine with all other applications but neither seem to generate the burst of 240 Hz.

Has anyone else had, and overcome, this problem?

Thanks,
Steve K0XP