HP41C On Button Oddity / Help please

[Vintage63]

Well, it might not be the same problem I had but yesterday I have used the 41 to register to this website and left it on.
I wanted to try again the card reader and the 41 wouldn't start at all.
Tried everything I possibly could, nothing.
Today I checked the batteries with a multimiter and they are well in the green area.
As I was already using my dremel for other contact cleaning jobs I passed the head on the contacts in the battery compartment and reinserted the batteries, the 41 fired up again, no uncertainties anymore :-)
Cheers
Marco