Maybe if you search the keyword above you will encounter a lot of problems with the Samsung galaxy S3 no signal, and in Singapore we often encounter problems like this. And most users do factory reset and most of it did not work.
When searching signal, and the network is set to manual mode it can detect other providers but do not get a signal.
When you face a problem like this try the following steps: 1. Disconnect the battery and SIM card and insert again 2. Check simcard if installed correctly 3. Perform Factory reset and wipe all data if no steps. 1 is not successful, 4. Try to change other SIM provider
If the above steps still do not work, which led to the Samsung Galaxy S3 searching / no signal most likely there is a hardware issue on the Samsung Galaxy S3 cpu you, immediately contact a reliable service to improve service, and you can contact us at 83888781 / 86111067.