Problem with Wireless Door Chime

[Urahara]

Bought this inexpensive wireless door chime couple of months ago which has a transmitter unit (where you press the button) and the receiver unit (the chime normally located inside the house). An example of such a unit : Amazon.com: Sunnybell ST60 3-Tone 16-Channel Wireless Door Bell,Door Chime With Strobe Light: Home Improvement

Recently it stopped working and thinking that the transmitter battery is flat, I changed the battery but it stopped working again after a day (the receiver battery is ok).

While trying to investigating what went wrong, I accidentally inserted the supposedly flat battery in reverse polarity, pressed the button, which of course gave no sound. But when I reconnected the battery in the correct polarity, the transmitter worked and the receiver unit chimed. This worked for a few presses, and the transmitter went dead again. If I repeat the above, I can get the chime working though only for a while.

Any idea what is happening? Also, which part is not working? If it is just a bad capacitor, I am wondering if it can be easily repaired.

Thks!

 

[Diver300]

A photo of the circuit would help.

 

[Urahara]

Here you go:

 

[colin55]

I think the frequency is slightly off-channel.

 

[KMoffett]

Are you sure it's the transmitter. I have wireless doorbells. When the receiver's batteries (8xC-cells) get low I may get a couple of chimes, then nothing. If you let it sit for a while you may get another chime. I finally replaced the batteries with a wall wart. No more intermittent operation.

Ken

 

[Urahara]

changed the receiver's batteries to a fresh set and it does not work. so it is not the receiver that is at fault.

the sequence I mentioned before : connect the transmitter's batteries upside down, press the button (no sound), reconnect the batteries in the right polarity, press, door bell chimes.

Anyone dare to offer an explanation?

Thks!

 

[colin55]

Adjust the frequency with a plastic screwdriver.

 

[shokjok]

Remove the receiver PC from the case and flip it over, scan it so we can be of further assistance.
I plan to interface a garage door opener to a door chime, and a remote door lock.