Here is another details of the switch housing. Blue marker indicates cracks that originated from sharp notch.
I reckon only about 2mm X 15 mm square of area that must withstand cantilevered housing of 60mm long. If the force required to close the hard copper leaf switch is 0.1kg then the root suffers 0.1kg X 60mm of bending load plus 0.1kg vertical load reaction, small loadings? maybe..but that small loads repeated over 200 times and with that sharp notch? exactly!...for quick fix I just hardwired & isolates the leads...at least the centrifuge works now, without the usual 'safety' feature though :)..
Another product I've observed is the famous mosquito hitter. We have used and throw away many of them, they're cheap and short lived :). The green one here last a month. Most annoying is that the switch of the lamp is on the wrong side, so when you put it on that side, you will unintentionally switch the lamp on, emptying the battery...yes the mosquito's is laughing at me :)...
Now we got another one, sturdier, better looking and ergonomics, very powerful, until I got that high voltage - low current power right on my leg..I screamed the **** off...yes the mosquito's are laughing even more louder ...sigh...ze power never the same again..absorbed by my leg I think :)
So in one evening with nothing to do, I opened both hitters..1350VDC mylar capacitor?..no wonder :)..
and 2 A3 rechargeable battery...now I know how NOT to buy another hitters...:)...watch out you mosquito's...!!