Partial Jag failure?

[techhelpbb]

Originally Posted by kamocat

I just checked inside.
No debris.
No signs of heat.
The resistance from 0v to vLow measures 0.3 ohms on my multimeter (the same as when I touch the leads together). I measured this between the 0v 6-32 screw and the lead of a low-side MOSFET.

It would be unlikely a simple digital multimeter could measure that small a resistance reliably with the currents it uses when measuring resistance. Though checking for continuity would confirm that there is connectivity and we know from the fact that it does work there must be a connection currently.

Also...if the resistor got very hot...it would heat the PCB and itself. That combined mass might take a while to cool off even with the fan.

Could it be that you melted the paste on that component and when it finally cooled off it closed again? One could also ask this question about the points to which the body of the resistor meet the areas designed to be soldered down.

In other applications I've seen surface mount resistors recover from overload before but usually it alters the resistance which you might not be able to measure with that meter. If it has altered that resistance by some appreciable amount it'll alter your current measurements. Do these current measurements seem proper for the mechanism in question?

Would there be some value in using a fixed, high power resistor as a load on the Jaguar and taking comparison measurements with another Jaguar? How about just trying to measure the current with another meter with a fixed resistive load?