Curious Cheap Doorbell

When I moved in, the house had several doorbells. There was a mains powered wireless doorbell plug with the remote button stuck to the doorframe. I couldn’t get this to work at all. I don’t like wireless doorbell a, they’re very convenient but seem to be incredibly unreliable. But maybe I’ve only tinkered with cheap ones that are unreliable by default. There could be some good ones.

There was also a traditional doorbell button with wires hidden inside the wall. They were connected to a cheap looking electronic doorbell unit behind the door.

So not judge the wiring. It is usually hidden by the curtain, so nobody knows.

I got this doorbell working with a bit of tinkering and some fresh batteries. It makes a loud electronic ding ding sound.

Occasionally a caller would tell me the bell didn’t work, and I’d fiddle with it and it would start working again. I took the bell push button apart and cleaned it.

It would still sometimes not work, so I fitted a new bell push

Not a Friedland 701

All was well for a while but recently the doorbell has been doing odd things. Instead of a ding ding it will sometimes make a shrill beep beep beep that’s reminiscent of a smoke alarm. Then the other evening a supermarket delivery arrived and the doorbell played a tune that went on for some time. I’ve never heard that before!

OK, a cheap battery doorbell with a speaker that plays different tunes – fairly standard. What’s curious is that there’s no switch on the unit to change the sound. Wheneve I test it myself it invariably goes ding ding. But when others press it, sometimes it goes beep beep beep and once I’ve had a musical tune.

I’ll take the doorbell apart later, but don’t expect to find much. I’ll probably buy a new Friedland bell in one unit – they’re been around since the 1970s and are very reliable.

My guess as to how the tune might get selected and why it’s happening now is that the original bell push that came with the bell had the selector switch inside it, and perhaps signalled which tune by a specific resistance put across the wires. My new bell push (and indeed the one I removed) are just standard switches. But in the wet and cold, and after a few days if not being pressed, maybe there’s extra resistance on the damp switch contacts that the bell interprets as a selected tune.

Best guess I’ve got! I was going to post this as “Mystery of the Haunted Doorbell”, but thankfully it’s not ringing jn the middle of the night with nobody there. It just sometimes plays a tune when you press the button.