Find all the connection ways to Lenovo s720 in the images below.
WARNING: You must be an expert to proceed with this operation. Please do not continue if you are not a qualified repairer, otherwise, you may damage your device. Learn how to repair mobile phones here
USB PORT CONNECTION WAYS
Check the VBAT, GND, DM, and the DP as shown in the image above with a meter. Make jumper connections to reestablish connections.
Make sure to connect the positive (+) terminal to the VBAT as indicated in the image above. The negative (-) terminal is connected to the GND in the PBC.
VOLUME CONTROL KEYS
To get the alternative part for the volume keys, unclip the touch pad (Sensor) and raise it up. the connection part will be found just under it. Use the picture provided to make your jumpers.
SIM SIT CONNECTION WAYS
Sorry that a complete SIM sit connection way has not been completely done. Check if the picture above can solve your device SIM sit.
For devices that cannot turn on because the power key is bad, connect the power key in the image above to the GND. This will automatically turn the phone on when a battery is inserted.
REC CONNECTION WAY
Follow the image below for the REC connection way. Not that this will be found at the back of the main PBC.