I'm trying to measure the current used by a 3.5" hard drive in an external enclosure. I connected my multimeter in series with the positive 12V power supply, but in doing so, the hard drive fails to startup. It tries to startup (I can hear mechanical movement) but quickly aborts and retries cyclically without success. During this process I can measure about 350mA of current (on the 10A meter setting) and a stable 12V -- of course, the device works fine without the multimeter in series.
I'm wondering what might cause this phenomenon and if its common or well-understood in general. I've tried with two multimeters, both of different grades and observe the same results. Could there be an in-rush current limiting device in the multimeter which is impeding a high-current demand of the hard-drive? The hard drive would draw the most current during the acceleration of its motor, which typically happens during startup.
I don't have a clamp meter, but I suspect using one would be best for this application as it removes the physical connection with the device.