Maybe you need to wait a little while after sending a power command before the TV will accept an input command. I've faced this with other control systems. Sometimes I can use an explicit 'wait' command, other times I can simply rearrange the command string, turning ON the TV first, then executing other commands, such as receiver, cable box, and input device commands. You may need to execute a few extraneous commands to devices that don't exist in your system.