Hi. I recently made a small mistake. I purchased one of those probe type "Made in China" soil moisture testers. There was a gardening workshop, and the UC Master Gardeners group recommended the use of these meters to prevent over or under watering.
The meter had no reading, even in soaking wet soil. It also had no reading in dry soil. The resistance, as measured by a DMM , across the probe tip was infinite. The meter was opened and the probe disconnected. The measurement of resistance across the D'Arsonval movement meter was similarly infinite. There were solder blobs and solder spray across the front of the meter, indicating a sloppy assembly technique. Since the case was now damaged, and the package was long since discarded, this meter could not be returned. It is likely that the probably now moved-on Chinese manufacturer would not accept it back anyway.
Since the probe part looked like a battery (dissimilar metals), a current reading was taken on the aformentioned dry and saturated soils. A reading of 6 microamps and 700 microamps were obtained, respectively.
Does anyone know the calibrations of the meter, offhand? Are these rmeasured values representative of the observed range?
If a decent range can be provided, the meter (without the movement) may be salvageable.