Thank you for your post,

    There are only a few items that will cause a black picture instead of video signal when a camera is plugged in.  Please check these items, so that we can assist you further:

1.  Lens Cap - The PT-351-V49 cameras ship with a lens cap inside the outer glass dome, to offer protection for the Varifocal lens.  Please ensure that the lens cap is completely removed before retesting

2.  Insufficient Power - Insufficient power with the PT-351-V49 cameras, can cause a black picture to appear, while the camera will still move properly.  This is due to not enough power to the image sensor.  Please ensure that you are using only the 12VDC 1Amp Power adapters that come with the PT-351-V49 camera to power this camera.  The multi-camera power boxes are not recommended, as they will not provide enough amperage per output.

3.  DVR Problem - If you are plugging the camera into a DVR, please plug the camera into a Television directly, as this will eliminate any possible causes in the DVR itself.  Some DVR Cards, such as our Alnet systems cards, do not take too kindly to cameras that are plugged in after the card is running.  With this type of DVR card, it is recommended that you exit the program and open it back up again.

Please let us know your findings, so that we may assist you further,
Thank you
Platinum CCTV Support
http://platinum-cctv.com