Loss of signal is a common issue that TVs of any brand or type can experience. The issue is no more common on the Toshiba Regza 42RV530U than any other TV, but this particular model does feature a few specific features that require some attention when troubleshooting to restore your picture and sound. Before spending time on the phone with a technical support representative or having the TV serviced, try addressing the problem on your own.
Turn the Toshiba off and back on. This may seem like an obvious step, but modern TVs will typically only rescan for a signal on all of its inputs when it has been powered off and back on. If there is still no signal after powering the TV back on, it is time to troubleshoot the physical connections on the TV itself.
Turn input lock off if it is on. Locate the "Locks" button on the Toshiba remote control and press it. Press the down arrow key on the remote and you will be prompted to enter the 4-digit security PIN that you specified during the initial set-up. Enter it and press the down arrow again until the input lock option is highlighted. Press the right arrow key and arrow down once again until the input lock display option is set to "Off." All inputs have now been unlocked, so check the TV for signal.
Unplug and replug the input connection cable or cables to check if a loose cable is causing the loss of signal. If you are watching a DVD player connected to the TV's upper front video inputs panel via RCA cables, simply unplug and replug all three RCA cables and check the TV for signal once again.
Switch to another TV component device using the input selection control. At this point, it is necessary to check if you are not getting signal on any of the TV's inputs or just on one single input. The input selection control is labelled "input," and is located both on the Regza's remote control and on its side control panel; press it a few times to see if you get picture and audio on any of the other devices that are plugged into the TV. If so, the issue is most likely isolated to the one input device that is not giving a signal and you would need to troubleshoot that device individually. If none of the inputs give any type of signal, it is most likely necessary to have the TV serviced or contact Toshiba technical support for further assistance.