Frequently asked questions about cameras

The specific performance is that all the photos taken become black and white images. The main reasons for achromatic failure are as follows:

(1) is the camera's poor focus. Because of defocusing, the chroma signal of 4.5 MHz is lost, and the image clarity is also seriously reduced. It is very important to check the focusing and current stabilizing circuits on the camera autofocus circuit board.

(2) The gain amplifier stage of the chroma signal is turned off, and as a result, the chroma signal is not output. Emphasis should be placed on checking all levels related to gain amplification in chroma signal channels, such as input and output amplification stages, automatic chroma control stages, buffer amplification stages, etc.

(3) The chroma signal is interrupted. The reason is that the signal transmission line is open or the signal is short-circuited into the ground, resulting in the camera only outputting brightness signals, and the inspection focus should be on the chroma channel integrated circuit.

The specific manifestations of this fault can be divided into two situations. One simple reason is that the image displayed by the viewfinder is blurred. Another situation is that the image output by the camera is blurred (at this time, the image displayed by the viewfinder must be blurred).

For the first case, that is, the viewfinder image is blurred, the main reason is that the focusing voltage of the viewfinder is unbalanced. The solution is to readjust the focus voltage.

For digital camera output image blur, the solution is as follows:

(1) is that the lens of the digital camera is not clean. Just wipe the dirt off.

(2) Improper adjustment of focal length. Especially when the digital camera is in manual focus adjustment,

The auto-focus function doesn't work, so the focus switch should be set to the auto position; In addition, if the shooting conditions are not suitable for autofocus, the focus switch can be set to the manual position, and the image can be restored to a clear state by manually adjusting the focal length;

(3) It is the fault of the camera circuit, which is mainly manifested in the poor focusing performance of the lens unit. At this time, it is important to check the focusing current stabilizing circuit. The main manifestations are poor definition, pseudo color and fixed spots on the picture. In this case, the poor quality of CCD sensor should be considered as the main reason after troubleshooting the above-mentioned focusing circuit. The output waveform of the front video of the sensor can be observed through the oscilloscope, and the poor performance of the sensor itself can be determined after troubleshooting the related peripheral components.

The reasons for the poor quality of the captured images are not only the faults of the camera, but also the faults of the video recording part, such as the pollution or damage of the magnetic head or the faults of related circuits.