I take it you meaning that when two different sources of AV are connected to each of the two AV sockets on the TV and you select say (No 1) input, it work's, but if you select (No2) it wont, if this is the case when the other socket doesnt work does the screen go blank? or will it just not respond to being switched in the first place? (if the screen going blank applies, "whilst in that state" switch the leads over at the back and see what happens) Another factor is, are you using the original remote control?