Modify Doorbell Receiver to run off 5v supply

[fatman57]

I have just purchased a solar powered door bell which was quite cheap. The button part is solar powered and sends a signal to the receiver which is powered by the mains. As a project I want to make the whole system run off a solar power source. I have taken the receiver apart and labelled the components, please see the image below:



If I wanted to bypass the current power supply circuit, which part would I supply +5v to (which is what I believe the rest of the circuit board to run on)? Can it be done? Many thanks for any input!

 

[Bluejets]

I'm guessing somewhere around where you have the 4.7v marked.
Anyhow, the basic arrangement for a 3773 is below maybe it will help sort it.

 

[dave9]

Power it up and measure the voltage at the transformer output. If that's pretty near 5.0V you can put the 5V input there and take the transformer off the board, or cut the trace from it to the capacitor(s) after it and put the 5V input at the capacitors.