A friend called me and told me his wireless mouse was not working.
First thing I did was ask him if he changed the battery. He said he was sure the battery was good and even though I knew that was the problem... he insisted on bringing it over for me to check.
What the heck, I'm having a slow day today.
When he got here, the mouse worked for a few minutes, then quit...so I told him I'd would replace the battery and try again.
He took a spare battery out of his pocket and said, "brought one with me , just in case."
After examining the mouse I could not even figure how it opened, so he replaced the battery himself and it worked fine.
(The old one measured 0.9v , surprised it worked even for a few minutes.)
Sheesh