When TV is showing no picture there are a few steps to take.
1. Make sure the TV and cable box are on. The most common cause of no picture is that the cable box is powered on, and the TV is powered off or vice versa. Make sure the both are powered on and check to ensure they are still plugged in. If they are on a power strip check that the strip is not off and/or if other devices on the strip are still working. If all devices on the strip are off and flipping the power strip doesn't work, get a new strip or contact IT.
2. Make sure the TV is on the proper input channel. If using an HDMI cord, make sure the TV is on HDMI 1 (or 2 or 3 depending on which spot the cord is plugged into on the TV.) Some TV's are still using Coax cables so the TV may need to be on channel 3 for this to show.
3. Check connections. Ensure that your cable from the TV to the cable box is tight and not loose on both ends. Also check for damage to the cord.
4. 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.
5. If possible, try using a different cord. Make sure you change the TV input to the correct connection type if you change it (Channel 3 for Coax cable, HDMI for HDMI cable, Component for Red/White/Yellow cables, Composite for Red, Blue, Green, White, Red cables).
6. 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.
7. 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.