It’s a WHSCL1V2 Scale - no matches in tags - anyway, in checking the batteries when it failed to work, I checked the voltage on the 4 AAA batteries; 3 were 1.3V, but the fourth had suffered “Reverse Polarity”!
Black to negative, red to positive, the needle tried to bury itself towards zero. Black to positive, red to negative it registered 0.8V! New batteries refreshed everything and it works fine.
I’ve only seen Reversed Polarity on Star Trek! It really exists! But, how? How is that possible?
Thanks.
chatGPT is your friend
Yeah, that’s a textbook case of a cell getting reverse-charged by the others. When multiple batteries are used in series, like your 4 AAA setup, one weak or dead cell can actually get pushed backwards by the combined voltage of the others. Here’s what happened in your case:
• Three cells at 1.3V = 3.9V
• One weak/dead cell starts to go flat while the device is still drawing current.
• The stronger batteries force current through the weak cell backwards, effectively reverse-charging it.
That’s why you saw:
• Black to the “correct” negative, red to positive = needle buried (showing reversed polarity).
• Black to positive, red to negative = 0.8V (confirming it’s reversed).