I really do not what's wrong to this Digiguard D0824, from AVTECH. I connect a total of 7 caremas only, 3 of them have about 250 meters long, other 4 have about 50-150meters long. However, only 5 cameras can view. 2 cameras with 250-280 meters long are not showing in this DVR.

To prove the problem, I connect these 2 cameras directly to a LCD TV, and it works fine. I really do not have idea what happen to this brand.

Anybody have idea please share with me. Thanks

What other troubleshooting did you try?

Did you try bypassing the long cables and connect the cameras directly to the DVR?