Check the batteries. When left on, the batteries will continue to dis- charge (and what kid turns things off?) and eventually ruin the battery.
This one should be a very close match. The T4508 is a foreign version of the T4500.
You are describing an open squelch. If this unit has a squelch control, adjust it until it quietens.
If the battery voltage drops below a certain point, it won't squelch. That could be caused by a battery that needs to be charged or a bad battery that won't charge up correctly.
you have opened up the squelch - refer to the manual to close and return radio to normal operation
Use scanning to monitor channels for transmissions or to find someone
in your group who has accidentally changed channels.
1. Short press MENU until the "Z" appears. The current setting
On/Off will flash.
2. Press either + or – to turn On or Off.
3. Press the PTT to confirm or MENU to continue set up.
Here is a link to the manual http://www.motorola.com/mdirect/manuals/FV200_userguide.pdf
motorola need service contacts are holding in it.