Yesterday I realised that our doorbell had stopped working. Last time this happened, I opened the chime box and discovered that a couple of the batteries had started corroding. I fixed it by replacing the batteries and cleaning up the contact strips inside.
This time the batteries were still good. I took the box off the wall for a deeper look and bit of a clean but didn’t manage to actuate the bell by putting a metal strip across the two contacts. Aha! – new chime box required, I thought. However, the thought struck me that I ought to check the external push button too and I’m glad I did, as that turned out to be the actual cause of the problem.
I could sound the bell by touching the two wires together and the contacts looked dark and oxidised, so I removed the bell push from the wall and took it inside to clean up. Once I’d figured out how to pop the contacts out, I looked up how to clean copper and came across one or two videos suggesting cleaning with a mixture of salt diluted in vinegar (producing sodium acetate and hydrogen chloride) and then neutralising the action of this mixture by washing with sodium bicarbonate diluted in water.
I don’t quite understand the chemistry but it worked a treat. Rather than spending money on the wrong part, I’ve managed to fix the problem, get the doorbell working and learn something in the process.