Home theater and home audio are becoming more and more popular in people's lives. What should inspectors pay attention to when conducting home audio inspection? Shandong audio manufacturers summarized the relevant content. If you think it is useful, don't forget to pay attention to the collection!
1. Audio inspection process
1) Packaging inspection
2) Visual inspection
3) Safety inspection
4) Function check
5) Special inspection (aging, wiping, tension, internal inspection, etc.)
6) Parameter test
2. High voltage test parameters
3. Function test
The difficulty of acoustic inspection is that the sound we hear is invisible (chaotic waveform on the oscilloscope) and can not be touched, and everyone's hearing is different. From the user's point of view, some people have their own preferences, some people especially hate the noise of the power amplifier, and some people especially hate the buzz of the bass. All these increase the difficulty of the test. We need long-term training, sharpening our hearing and accumulating experience to identify various product defects.
4. Tuner (radio) inspection
1) Band switch (button for electric tuning products) inspection
Common problems: no function, poor function,
Cause: poor incoming materials, poor assembly or foreign matters such as rosin infiltrate the switch
2) Frequency coverage check
Inspection method: adjust the console to 560khz (low end), 1600khz (high end), 88mhz (low end) and 108MHz (high end). The test signal sent by the factory shall be clearly heard
Common problems: coverage deviation (phenomenon: no signal is heard at high and low ends)
Cause: Factory three-point adjustment deviation.
3) Sensitivity (stop sensitivity) check
Inspection method: manually adjust the console to 600kHz / 1000khz / 1400khz 90mhz / 98mhz / 106mhz, and the test signal sent by the factory shall be clearly heard. The sound shall be loud and undistorted, and the electrically tuned one shall stop at the above frequency
Common problems: random stop, low sensitivity, sound distortion
Cause: Factory three-point adjustment deviation, unbalanced high-voltage amplifier circuit, etc
4) Full band sound quality inspection
Inspection method: from low to high, use a cloth wrapped wooden hammer to knock the product. The whole frequency band should have clear and distorted sound.
Common problems: howling, clapping, ringing, noise.
Cause: false welding, false welding, too close to components, shaking of components
5) Stereo (lighting sensitivity) check
Inspection method: adjust the console to the factory generated stereo frequency, and the difference between stereo and active channel shall be clearly heard
Common problems: no stereo, separation check, light (indicator) not on
Cause: poor adjustment of 38kHz subcarrier signal
5. Inspection of recording base
1) Functional inspection of movement
Inspection method: take a tape with the anti erasing film removed, put it into the card holder, and test the fast forward, rewind, anti erasing and self stop functions
Common problems: no function, tape winding, mechanical noise
Cause: poor incoming materials and assembly of the movement, and the movement touches other components
2) Recording / playback check
Inspection method: take a blank tape, put it into the card holder, test the recording, take a music tape, test the playback, and knock the product with a cloth wrapped wooden hammer
Common problems: no recording, recording low noise, recording howling, playing low noise, distortion, channeling, mono low, shooting noise, etc
Causes: inaccurate belt speed adjustment, poor azimuth angle adjustment of magnetic head, poor welding, poor microphone, self excitation of magnetic bias circuit, etc.
6. Power amplifier inspection
1) Input port, selection switch check
Inspection method: connect each input port, press each switch, and check the output
Common problems: no output, poor switch, key sound
Cause: poor incoming materials and poor welding of switches
2) Sound quality inspection
Inspection method: play familiar music discs and test discs with DVD or CD, input the power amplifier, adjust the tone and volume, and knock the product with a cloth wrapped wooden hammer
Common problems: AC sound, distortion (sound sand, sound dull, sound broken, sound shaking, sound floating, etc.), beat noise, poor tone function, etc.
Causes: excessive power ripple, mismatch between high and low frequency of the circuit, poor welding, etc.
What do inspectors need to pay attention to when doing home audio inspection? Here, we conduct inspection and test from six aspects. In fact, there are many kinds of test items. You should take appropriate measures in practical application. For more information, please visit our website https://www.wenguangzhineng.com Consult.