No video, appears to be no video sync, diagonal rows of dots. Not an HDMI TV, switch is in TV position, cable checked ok by using a new cable, same problem

It appears that the Bytecc 4K2K LPCM 7.1 Extractor may not be fully compatible with the ARC (Audio Return Channel) feature on your ONN Roku 40 TV. Here are a few suggestions to potentially solve the issue:

1. Ensure that both your TV and the Bytecc 4K2K LPCM 7.1 Extractor support the ARC feature. Check the user manual for the specific HDMI port on your TV that supports ARC, as not all HDMI ports may have this feature.

2. Double-check your TV audio settings. Make sure the audio output is set to HDMI ARC, and if there's a setting for audio format, choose LPCM.

3. Try using a high-speed HDMI cable that supports Ethernet, as the ARC feature requires this type of cable.

4. Perform a factory reset on your Extractor and reconnect it to the HDMI ARC port on your TV.

The cable box signal on the components video have a too high refresh rate frequency, that is the reason for the lines.
Use RCA cables or an alternative connection.
Other solution is changing the display out settings for cable box (from PAL to NTSC etc.)

Use VGA adapter to HDMI works for video
Sound is carried over stereo cable
What you are doing needs 2 cables
Video cable for video
Sound cable for sound
Using TV for monitor VGA to HDMI 32" at 120 refresh is best dot pitch .
over 32" dot pitch is lower may become grainy resolve place monitor away more from you when using over 32" TV 120 refresh is important

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

try connecting your blue ray player to HDMI 1.
A) If it works there, then you know the port on the TV is OK & the problem is with either your HDMI cable or your cable box.
B)If it still doesn't work then you may have a problem with the port on your MAIN PCB. if it's a new TV your warranty will cover that as long as the input connector is not physically broken.

Sound on means audio section is ok. No picture is video board problem. Pl check input cables. Or give Hdmi cable input. Disconnect all inputs switch on u should get plain raster that is only dots on screen, or blue back screen, if nothing contact authorised dealer,

Don't used the Blu Ray player on the tv HDMI out put hub.Used the connections for of the Blu Ray player connections by a S-Video cable for the video and the RCA component cable R,W for the connections for the audio out.The high Def.cable box will not work for high Def. this way,but the Blu Ray player will.

optic block failure is the dotty appearance use your model number to shop around for a new one and the coaxial input's are easy to break loose so use s-video if at all possibly ok

In the U. S., we would see "No signal" if there is a problem with picking up the TV station. "No sync" may be equivalent; the tuner may be detecting a signal, but it isn't strong enough for the TV to pick up the synchronization pulses needed to decode the picture information.

You can check this by connecting a known-good video game set, DVR or DVD player to the TV and verifying that the TV properly shows that.

Worst case: you're only using HDMI inputs, and the HDMI circuit was blown out by static electricity during the take-down or reconnection processes. That's been a problem with some cheap HDMI external switches. Before assuming this, try a different HDMI cable; there are some low-quality types with fragile connections at the end.

onkyo receivers have a problem, see

http://www.hdtvsupply.com/hdmi-cable-booster.html