Hi I have a Jovision brand DVR model JVS-AK1016-PLUS which I had to take it to repair thinking that it had broken, however and luckily it was the source without harming anything but the replacement of it. To all this the technician who saw me, honestly told me is the source so the DVR revived to change it without any problem, apart from that the problem is that the technician told me that all channels (it is for 16 cameras but currently I have 8) they work well. He told me that he reset ALL values. Apart from this, when I arrive at my house and connect it I see it does not visualize any camera ... I tried changing the source of the cameras, connecting one by one and nothing ... nothing is displayed. The DVR is on NTCS and I tried it with PAL .... I don't know what to do. The cameras turn on well without problems I could see that they turn on well but none is seen on the DVR in any of the 16 channels even if you connect 1 by 1. Where to start testing? What to do?