When cable TV is showing a snowy screen there are a few steps to take.
1. Make sure the TV itself is on channel 3. Note: The cable box channel and the TV channel are different things. Channel 3 is the input of most TV's using a coaxial connection and if the TV comes off that channel it will show a snowy picture.
2. Check connections. Ensure that your coax cable from the TV to the cable box is tight and not loose on both ends. Also check for damage.
3. Power cycle the equipment. This means to unplug the device for 30 seconds, and plug it back in. 30 seconds is important because there are capacitors inside the equipment that will hold onto an electric charge for a short time. If you just unplug and plug back in right away the device is not actually reset since it does not release that electric charge. Unplug both TV and Cable box to ensure all devices receive a nice reset. After 30 seconds plug then back in and wait about a minute for the cable box to resync with the headend and provide the TV with a signal again.
4. If possible, try using a different cord. Either another coax cable (cable with screw on ends), or best would be using an HDMI cord if the box allows it. Make sure you change the TV input to the correct connection type if you change it (Channel 3 for Coax, HDMI for HDMI, Component for Red/White/Yellow cables, Composite for Red, Blue, Green, White, Red cables).
5. Check to see if any other devices are working on the TV. DVD Player, Video Game Console, VCR, etc. If another device is also not working then the issue is likely the TV. If another device IS working then the issue may be the cable box. A good step to try is to take the working device, and use its cord on the cable box. For example, if the DVD player is working, take it's HDMI cable out of the DVD player and plug it into the cable box. If you still get nothing then the box is bad. If you get a picture then that TV connection is bad.
6. If all else fails contact your cable provider for a tech appointment. You will need the address and business name at minimum. Please let IT know you are doing so and what steps you took to get there. Usually it is best if someone such as the RS or PD who knows the house schedules can make the appointment, as someone will need to be at the house for the tech to come out. Also if there are any client behavior concerns they can take that into account when scheduling.