Re: P6302 Current Probe DC Offset


Jeff Davis
 

Not much progress last night due to other commitments, but did try a couple of things.


Injected a ~10 MHz signal into the line using one of the coax braids as a return. Passed a scope probe over the cable from end to end, saw the RF, but didn't see any discontinuities that made me think there was a disconnect. Did the same thing on a known good wire in the same cable and saw pretty much the same thing.


Measured the capacitance between the bad wire and the same coax braid. Got around 870 pf. Then measured the same thing for the known good and presumably longer wire. Got about 770 pf. Can't figure out why the supposedly longer wire reads lower capacitance. The wire I picked isn't connected to anything but the transformer shield. Hmm.


Both of these tests were done from the connector end with the probe still attached to the cable. I think the next step will be to remove the probe from the cable so I can test from both ends with no concerns about the circuitry at either end.

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