Troubleshooting of Common Faults of multimedia speakers

Source: blog China

Today, computers are moving towards multimedia and intelligent development, while speakers are an important part of multimedia devices. It can be said that speakers are the most direct computer peripherals in addition to displays, its quality directly affects the effect of multimedia computers. The following describes some common troubleshooting methods for multimedia speakers:

When the speaker does not sound or only one sound, first check whether the power supply and connection line are connected properly. Sometimes excessive dust may lead to poor contact. If you are not sure whether it is a sound card problem, you can change the audio source (such as connecting to the walkman) to determine whether it is a problem with the speaker. When determining whether the speaker is faulty, check whether the speaker sound ring is burned out, whether the speaker sound ring leads are broken, whether the feeder is open, and whether the amplifier is properly connected. When you hear the sound from the speaker is relatively empty and the sound field is scattered, pay attention to whether the left and right sound channels of the speaker are reversed. You can consider switching the two sets of audio cables. If the speaker sound is low, check whether the speaker quality is inferior and whether the Sub-speaker phase is reversed. When the speaker has obvious distortion, you can check whether the bass, 3D, and other adjustments are too large. In addition, the speaker sound ring skew, speaker core deviation or magnetic gap debris, speaker Basin Deformation, amplifier feed power too large will also cause distortion.

When there is a speaker noise, it is generally necessary to determine the source of the noise first.

1. First, test the speaker's own noisy on the recorder or radio. If yes, the speaker's own problems can be changed or repaired. The speaker is mainly caused by the crack of the speaker basin, crack of the speaker joint, loose of the speaker rear board, unfixed and tight speaker basin frame, and loose speaker surface network.

2. Change the sound card to a slot and try to stay away from other plug-ins, such as the display card, Modem card, and nic. Especially the display card has the strongest bandwidth and may interfere with any plug-in card including the sound card.

3. Unplug the audio cable from the sound card for testing. If no noise exists, it indicates that the audio cable is caused by this audio cable. You can change the audio cable or the sound card.

The following describes several repair instances.

Example 1: Repair of Shock Wave speakers

Fault symptom:

A pair of Shock Wave Anti-magnetic speaker with a rated power of 30 w. The speaker suddenly has no sound during use.

Troubleshooting:

First, I checked the appearance of the speaker. I didn't find any exceptions. I switched on the power and heard the noise. This shows that the speaker didn't burn out. I touched the back cover of the speaker and found that the back cover was gradually changing to hot. Because the back cover of the speaker is used as the heat sink of the Power Amplifier Integrated Block, It is preliminarily determined that the power amplifier Integrated Block of the speaker is damaged. Cut off the power supply, open the back cover of the speaker, observe the power amplifier circuit of the speaker, no signs of exceptions in the circuit, capacitor resistance and other components. After the power supply is switched on, it is found that in addition to the power amplifier Integrated Block is particularly hot, the bridge is also very hot, and the initial judgment is that the power amplifier Integrated Block is likely to be damaged.

Replace the bridge and remove the soldering tin on the four pins of the bridge with a soldering iron and a tin-absorbing device. After the power-on is switched, the fault is still found; then, the power amplifier Integrated Block is replaced. The TDA1521 power amplifier Integrated Block has nine pins and is tightly arranged, so its disassembly is complicated. First, remove the screws from the power amplifier plug-in, and then slowly remove the soldering tin of each pin on the plug-in. During installation, note that there should not be too many tin on each pin, otherwise, adjacent PINs may be short-circuited. Pay special attention to tightening the screws on the Integrated Block so that the integrated block can be closely integrated with the back cover of the speaker to achieve good heat dissipation. After the Integrated Block is changed, the fault is rectified.

Example 2: Eliminate the noise caused by the microphone

Fault symptom:

A compatible host causes various noises when connected to the microphone, including the noise of the CPU fan, hard disk, and Optical Drive.

Troubleshooting:

First, let's analyze the reasons that cause noise on multimedia computers.

1. if you do hear the noise from hard drives, optical drives, and CPU fans, it may be that the filter circuit performance of the motherboard and power supply is poor, the impact of interference signals from hard drives, optical drives, and CPU fans cannot be filtered out. Reducing the power cord of the IDE cable and the CPU fan can reduce the impact of the corresponding equipment. You can also try another power supply.

2. The connection between the microphone and the sound card does not use a shielded line or the screen line is not properly grounded. noise may occur when high-frequency interference signals are input by the microphone string. In this case, the noise should disappear after the microphone is unplugged. If it is the impact of microphone connection, do not use the Screen Shield line, you need to use the Screen Shield line: If the screen is used, use a multimeter to check whether the outer metal screen of the screen line is connected to the chassis, eliminate the impact of poor grounding. In addition, the signal line from the sound card to the source speaker should also be shielded and grounded.

3. use the "attachment"-"Drawing" command to open a high-color image, cut a piece, and drag it quickly with the mouse. If you can hear the "brush" sound when dragging, this is due to the impact of high-frequency radiation caused by the motherboard and display card in the machine. The sound card is inserted in the expansion slot away from the display card, and the sound card is shielded and grounded with an aluminum Screen Shield (pulling box ), this reduces the impact of high-frequency radiation.

4. check the connection between the speaker and the sound card. The ALS007 sound card has two audio output sockets: Line Out and SPK. The Line Out outlet outputs audio signals without amplification (high impedance ), it is used to connect the source speaker or amplifier. The SPK outlet outputs the audio signal amplified by the sound card's Built-in amplifier (low resistance) and is used to connect the passive speaker or speaker. If the input line of the source speaker is mistakenly inserted into the SPK outlet, noise will be generated due to the distortion caused by impedance mismatch and audio signal (including noise signal) amplification.

If you are still not satisfied with the above measures, you can try another sound card. If the fault is caused by the sound card, check the electrolytic capacitors C4 and C20 next to the ALS007 chip on the sound card, if the capacity of the two capacitors decreases, the low-frequency noise cannot be filtered out, and the two capacitors are connected to one of the three equal to 30 ~ PF small capacitor, can filter out high-frequency noise.
Example 3: a usb Speaker cannot play audio CD.

Fault symptom:

A new USB speaker is normal, but the audio CD cannot be played.

Troubleshooting:

This is because many CD-ROM players in computers do not support direct playback of digital audio on the CD disk with a speaker. Therefore, before using a USB speaker, be sure to see the compatibility of the CD-ROM driver.

After the USB speaker is installed as required, go to the control panel, go to the multimedia Properties window, and select the newly installed USB speaker as the preferred audio playback device. In addition, you should select the "This CD-ROM device can play digital CD audio" option. If this option does not appear or becomes grayed out, it means that the CD-ROM drive does not support digital audio.

Example 4: each time the speaker is started, there is noise.

Fault symptom:

After a computer is in use for a period of time, the speaker is noisy every time the host starts up.

Troubleshooting:

First, change the speaker. If the fault persists, it means that the speaker is not in the speaker itself. After the SRS is changed, the noise will be eliminated and everything will return to normal.