I have just got a KD-55XD8005 which was bought for me by my cousin who works for Sony. This is a reconditioned model. I got the TV yesterday and plugged it in and removed my old Panasonic TV. After plugging in the TV and plugging my Sky HD+ box into HDMI 1, PlayStation 4 into HDMI 2 and my XBOX 360 into HDMI 3.

I turned on the TV and went through the initial set up process. Once that was complete I went to HDMI 1 where the Sky HD+ box was plugged in and received the 'No Signal. Check the external input or select another input using the INPUT buttons' comment in the bottom right. This was the same for both the PlayStation 4 and my XBOX 360. The TV works fine for Netflix, YouTube and other on demand services like BBC iplayer and Channel 4 on demand.

The TV recognises that each of those are plugged in as it shows the symbol and also states that a sky box and PS4 are plugged into it and states it on the HDMI port. i have tried all sorts of things to get this fixed. I have done a factory reset, I have unplugged everything and plugged things in 1 by 1 to isolate the issue. I have installed all updates on the TV to make sure it's up to date with the latest software. There is nothing wrong with the HDMI cables or the devices as everything worked perfectly fine only a few minutes before switching from the Panasonic TV. Everything also works perfectly fine on a different Samsung TV. 

I spent about 3 hours last night trying to look online for a solution and found nothing helpful. I am completely out of ideas as there is no reason that the devices shouldn't be displaying on the TV especially as they work on 2 other TVs.

I would try to make use of Sony's tech helpline however that is only Monday - Friday 9-6 which is useless for me as I am at work all day. I really need some help and can only hope someone has an idea about how to help me.