The adjustment and test methods of the hottest DV

The adjustment and testing methods of DV camera and video recorder are made public.

camera is a high-tech product integrating camera system and video system. This machine adopts precise mechanical technology. Advanced photoelectric technology, high-density magnetic recording technology, large-scale integrated circuit technology and video and audio digital technology. The camera system is composed of camera lens, filter, CCD, image sensor, CCD drive pulse generator, automatic control circuit, automatic white balance control circuit, synchronous signal generator, sample and hold pre amplifier, signal processing circuit, pal encoder, Image Finder drive circuit and picture tube; The video recording system consists of video and audio head, head amplification circuit, brightness/chroma signal processor, character generator, loading motor, loading driving circuit, microcomputer control circuit, audio signal processor, operation circuit, servo circuit, driving circuit and mechanical device, and is also equipped with regulated power supply and adapter. In order to keep the camera in the best working condition, the electrical and mechanical parts of the camera must be adjusted and tested correctly

I. commissioning of electrical part

1 Camera part

1) adjustment of Image Finder (1) adjustment of line oscillation frequency of Image Finder, a 47 is connected between the video input end and the ground μ F ／ 16V dielectric capacitance, test with a frequency meter, adjust the row synchronous potentiometer so that the reading of the frequency meter is 15625HZ (± 100Hz), and remove 47 After adjustment μ F ／ 16V dielectric capacitance. (2) Adjust the vertical amplitude of the image finder and the measurement and shooting test card of the image center, and adjust the vertical amplitude potentiometer so that the circle of the test card is tangent to the top and bottom of the Image Finder display screen (that is, the image does not roll up and down); In addition, adjust the center magnet so that the image center is located in the center of the Image Finder display screen. (3) Adjust the brightness and contrast of the Image Finder shoot the gray card, adjust the brightness potentiometer and contrast potentiometer, so that the gray card level displayed by the Image Finder is clear. (4) The Image Finder converges, adjusts the shooting resolution test card, and adjusts the convergence potentiometer to optimize the convergence effect of the image finder. (5) The focus of the Image Finder adjusts the camera to align with the circular diagram, and adjusts the focus potentiometer to optimize the clarity of the image finder

2) adjustment of the auto focusing part (1) the adjustment of the bias and gain of the auto focusing amplification circuit is tested with an oscilloscope, the focusing ring is adjusted to the wide-angle position, and the infrared receiver is covered with black paper, and then the bias potentiometer and gain control potentiometer of channels A and B are adjusted to minimize the amplitude of the measured signal waveform. (2) The adjustment of the dual gain control level is tested with an oscilloscope, the focus switch is turned to manual, the camera lens is covered with a lens cover, and the dual gain control potentiometer is adjusted to make the measured signal level 16 ± 0.5vpp. (3) The adjustment of infrared output level is tested with an oscilloscope, and the dark scene is photographed (the distance between the camera and the dark scene is controlled within 2 meters). At this time, the measured signal level is 3 ± 0.12v. (4) Adjust the vertical position of the sensor, control the distance between the camera and the test card within 3 meters, shoot the automatic focus card, and adjust the screw on the sensor to make the image focus best. (5) The digital voltmeter for adjusting the motor speed is connected to the motor power supply end to shoot white objects (the distance between the camera and the white objects is controlled within 1 meter), and then adjust the motor speed control potentiometer so that the voltage at this point is 4.3 ± 0.1V

3) after focusing adjustment, align the test card within 3 meters (the light illumination of the test card is set at 50 to 100 lux) to take various ways of zoom shooting; Push the lens and adjust the lens focus ring to optimize the image on the monitor; Pull the lens and adjust the focus adjustment point until the image on the monitor is the clearest

4) the dynamic convergence adjustment is tested with an oscilloscope. The camera is aimed at the white card, and the dynamic convergence parabolic wave, sawtooth wave potentiometer and field parabolic wave, sawtooth wave potentiometer are adjusted to make the waveform displayed by the oscilloscope flat

5) the electron beam current adjustment is tested with an oscilloscope, shooting high brightness scenery, adjusting the electron beam current to control the potentiometer, so that the waveform amplitude of the oscilloscope is 1.4 ± 0.1vpp; Adjust the automatic electron beam optimization (ABO) control potentiometer so that the waveform amplitude is 2.2 ± 1.1vpp

6) the automatic aperture control (AIC) level adjustment oscilloscope is connected to the video output end of the A/V output connector, shoot the gray card, adjust the zoom ring, and make the monitor display the gray card; Then turn the chrominance gain potentiometer counterclockwise to the end, and adjust the AIC potentiometer to make the measured video signal amplitude 700 ± 10mvpp; After adjustment, turn the chroma gain potentiometer to the middle position

7) automatic control (AGC) level adjustment oscilloscope probe is connected to the corresponding test point through a "20K Ω" resistance, take a gray card, and adjust the AGC potentiometer to make the measured signal amplitude 600 ± 50mvpp

8) color subcarrier frequency adjustment is tested with a frequency meter, and the color subcarrier frequency control potentiometer makes the reading of the frequency meter 4.43mhz

9) color subcarrier level adjustment is tested with an oscilloscope, the gray card is photographed, and the color subcarrier gain control potentiometer is used to make the measured signal amplitude 700 ± 5mvpp

10) connect the color synchronous level adjustment oscilloscope to the video output end of the A/V output connector, shoot the gray card color matching synchronous level control potentiometer, so that the measured signal amplitude is 280 ± 15mvpp

11) chromaticity gain and phase adjustment vector oscilloscope is connected to the video output end of a/V output connector, and the color bar test card is photographed. The color bar vector dot falls in the field lattice corresponding to the oscilloscope

12) adjust the center of the line and field. The camera aims at the focus card for shooting, and adjust the potentiometer of the line and field center so that the circular center of the focus card is located in the center of the monitor screen

13) adjust the line amplitude and line linearity with an oscilloscope, shoot white cards, adjust the line amplitude potentiometer to minimize the amplitude in the middle of the measured signal waveform (at 4.3mhz), and adjust the line linear potentiometer to minimize the amplitude at the beginning of the signal waveform; Adjust the linear top control potentiometer to minimize the amplitude of the whole signal waveform

14) the field amplitude adjustment is tested with an oscilloscope, the white card is taken, and the field amplitude potentiometer is adjusted to minimize the parasitic beat signal amplitude of the waveform

15) the field edge effect is tested by oscilloscope, and the field edge potentiometer is adjusted to eliminate the video signal

16) the adjustment oscilloscope of the black bias level is connected to the video output end of the A/V output connector, cover the lens with the lens cover, and adjust the brightness to control the potentiometer so that the amplitude between the black bias level and the center line of the waveform is 85 ± 5mvpp

17) connect the black spot adjustment oscilloscope to the corresponding test point through a "20K Ω" resistance, cover the lens with the lens cover, adjust the black spot to make parabolic wave, sawtooth wave potentiometer and field parabolic wave, field sawtooth wave potentiometer to make the measured signal waveform flat

18) drag shadow adjust the shooting gray card and adjust the drag shadow control potentiometer to eliminate the drag shadow of excessive black gray and excessive white gray in the horizontal direction

2. The adjustment of the video recorder part

1) record the chromaticity level adjustment, use the oscilloscope to test, turn the brightness potentiometer clockwise to the bottom (so that the brightness signal disappears), send the color bar signal, and use the toner potentiometer to make the measured chromaticity level 45 ± 5mvpp

2) record the brightness level adjustment and test with an oscilloscope. After sending the color bar signal into the tape box (the machine is placed in the playback state), adjust the brightness potentiometer to make the measured signal waveform amplitude 150 ± 10mvpp

3) adjust the audio bias level, connect the digital voltmeter to the corresponding test point, install the tape and place the machine in the recording state, adjust the audio bias potentiometer, so that the measured signal waveform amplitude is 2.9 ± 0.1mv

4) adjust and measure the audio playback level with an oscilloscope, replay the 1kHz signal test band, and adjust the audio playback potentiometer so that the measured signal waveform amplitude is 260 ± 5mvpp

5) the PG phase shifter is adjusted and tested with an oscilloscope, the color bar signal test tape is replayed, and the PG phase shift control potentiometer is adjusted so that the rear edge of the pulse falls 6.5 ± 0.5h before the field synchronization pulse

6) E-E level adjustment is tested with an oscilloscope, input the color bar signal, and set the machine to the state of "Zhejiang market charging 1560 ⑴ 590 yuan/ton stop", so that the measured signal amplitude: a=1 ± 0.1vpp, b=0.6 ± 0.1ypp

7) adjust the speed of the main shaft motor with an oscilloscope, send a color bar signal, set the machine to the recording state after loading, adjust the speed control potentiometer of the main shaft motor, so that the sampling pulse on the PG pulse remains stationary or moves slowly

8) the speed adjustment of the drum motor is tested with an oscilloscope. After loading, the machine is set to the recording state, and the speed control potentiometer of the drum motor is adjusted to keep the sampling pulse on the PG pulse stationary or move slowly

II. Adjustment of mechanical part

1 Inspection and adjustment of torque 1) inspection and adjustment of braking torque remove the cassette bin, make the camera in the "stop" state, install the torque meter and adapter on the belt supply disc, and turn the torque meter clockwise. At this time, the reading of the torque meter is 140 g/cm; If the torque meter is installed on the take-up reel and the dynamic torque meter is turned counterclockwise, the reading on the torque meter is 80 g/cm. 2) Inspection and adjustment of playback, fast forward and rewind torque remove the tape box bin, install the torque meter and adapter on the take-up reel, cover the head with black tape to detect the sensor, and the torque meter reading during playback should be 80-110 g/cm; The torque count during fast forward should be 400 g/cm; If the torque meter is installed on the belt supply tray, the torque reading when the rewinding machine is hoisted to the preset place should be 400 g/cm

2. Adjust the tension arm. Hang the tension arm spring on the spring fastener (see Figure 4) B and push the tape box bin to the download position. The camera is placed in the replay state, and cover the belt tail detection sensor at the supply end with black tape. After the threading action is completed, loosen the fastening screw of the tension belt, adjust the position of the tension arm and the belt tail detection sensor at the supply end, so that the distance between them is 0.6-1.2 mm, and then tighten the fastening screw of the tension belt

3. Adjustment of back tension the measurement of back tension can be completed with two different measurement units of test tape (usually called back tension test tape a or b). First place the camera on a flat table, then push the reverse tension test belt a into the tape box bin, and put the machine in the playback state. At this time, the measured reading should be in the range of 27-38; If the measured value is too high, hang the tension arm spring at a in Figure 4; If the measured value is too low, hang the tension arm spring to Fig. 4B. In short, when the reverse tension is normal, the image released with the test Belt should be free of distortion

4. Adjustment and measurement of the guide roller on the take-up side and the supply side loosen the hexagon screw on the base of the tape guide post, and use the hexagon screwdriver to adjust the guide roller clockwise, so that the lower edge of the tape at the outlet is aligned with the guide angle of the drum; Turn the test oscilloscope to the "100mV/div" gear, adjust the magnetic trace tracking potentiometer to the middle position, replay the black-and-white test tape, and then adjust the belt guide roller on the belt take-up side counterclockwise, so that the test point tp204 of the ic202 pin of the video head amplifier is shown in Figure 5. The right envelope amplitude of the measured signal is the maximum; Similarly, adjust the belt guide roller at the belt supply side counterclockwise to maximize the left envelope amplitude of the signal measured by tp204

5. Adjust the position of the voice control head. When the tape is running, carefully observe the lower edge of the voice control head so that the distance between the lower edge of the head and the lower edge of the tape is 0.25 M. the host stiffness refers to the maximum m that the principal can bear, such as