Samsung has a wide array of televisions, including several 40-inch high-definition TV sets. Like any other piece of modern technology, there are a wide array of issues that can arise with your TV set. Many of the problems that you may find cropping up with your 40-inch Samsung TV can be fixed with a few troubleshooting methods including tightening all cable connections.
Inspect your cables for loose connections to your TV or cable box. If your picture is pixelated or cutting in and out, this can be due to a loose connection between the cable leading to your television or even the cable leading to your HD receiver.
Swap out your HD receiver with a different model. If you have checked the cables and are still experiencing image problems, the problem could be with your HD receiver, whether it be your cable box or satellite receiver. Swap the box out with a new one and see if this fixes your image problems.
Press the "Menu" button on your Samsung TV remote, and change the image brightness, contrast, and colour settings if your image colours seem either too dull or too bright. Likewise, if you are seeing outlines around images on your screen, adjusting your sharpness settings.
Adjust your TV's aspect ratio. If your screen image is distorted, either squished or elongated, press the "Display" button on your TV to switch the many different aspect ratios until you find one that looks right.
If you are experiencing power issues with your Samsung TV, your best option is to have a professional look at it. Tampering with internal components will void your warranty, making future repair a difficult proposition.