■ ■ ■ 2. .1 Speaker works with. .
Some time ago my Cruiser R201 TII, speaker suddenly to the right of the trumpet, and a few line back and forth. But found the noise is very heavy and music tastes changed. Note that noise as volume changes and the table lamp open larger touch speaker thermal backplane also larger (electromagnetic problem?).
Suspected internal speaker with circuit burned? . .
Multimedia sound "humming" noise causes and solutions.
Multimedia audio used for some time, often some strange problems, jar friends often ask questions of the "buzzing" sound problem is one of them. The failure of the "failure point" involves a relatively large, the need to edit an article to clear up doubts to the users. .
Humming noise performance phenomena from the following aspects of the analysis:.
1. 2.0 Speaker did not answer the sound source in a time of hum, shown in Figure 1, 1900TII power drawings. .
Old versions of R1800TII (1900TII), D1080, even before the course for users of high-end T200B hivi, have experienced similar problems.
Remove the input signal connection, the boot state, close to the woofer Department obvious drone can be heard in the dead of night, that buzz more apparent. Can also be said that this is the sound of background noise, and some friends will not agree, I feel I make a fuss. In fact, this problem can be improved. .
Personal analysis is as follows:.
Active Speaker relatively small internal volume, general EI Type Transformer (own relatively large magnetic flux leakage), and the amplifier board (or slightly worse performance of some anti-magnetic speaker unit) is very susceptible to interference between, resulting in speaker producing a low "hum "sound, when adjusted EI transformer installation location or direction, the drone can be reduced, (using high-quality beef or EI transformer ring better shielding measures, hate the" Om "sound can be greatly reduced). .
Hivi D1080 before this, (including the Cruiser's R1800TII/1900TII..) In the details, manufacturers should pay more.
I have been dismantling Edifier R1900TII/1800TII, EI transformers used are common, this problem exists, has tried to screw removal of the transformer, the transformer away from the amplifier board, greatly reducing interference. The adjustment to that position, disassemble the future to adjust according to circumstances, can minimize the drone!!!!. .
Some of the long life of multimedia, the transformer itself emits low hum, tedious, because transformer silicon chip just loose or exception that caused the transformer itself of noise. We can think of ways to reinforce the Silicon, the simple point is with a small hammer struck the side of the sheet, the majority of cases, the organ sound. (If the noise is particularly serious can only replace).
As T200A / B this high-end 2.0 speakers, the user's requirements higher, is forgiven. .
The above is analyse ideas, for reference, sometimes details determine success or failure, caused manufacturers to pay attention to.
2. Rectifier filter capacitor or damage caused by noise. See R1900TII power drawing of the circuit with a typical bridge rectifier circuit. We first briefly look at the principle of the circuit:. .
As shown in the figure. Power circuit (the bottom part of the drawing): after the fuse 220V (F), and after entering the switch S, transformers transformer primary secondary output 18V AC dual, dual fed by 18V VD1 composition of bridge rectifier circuit circuit, after bridge rectifier and C1, C2 (6800UF/35V) filter, the output voltage is approximately plus or minus 25V% (U = 1. .414 * 18V), positive and negative for two 25V power amplifier chip LM1875T power supply.
When the filter capacitor C1 or C2 when the failure will cause buzzing noise, seriously affect the listening effect. .
In other cases, but when the bridge rectifier circuit one arm (some say is a simple rectifier tubes), open (or damage), the output voltage will be significantly reduced (down to about half), at this point, the driver issue whistling noise or loud hum, not for normal use.
Both cases, easier to repair, how to determine whether the failure of filter capacitor it? ? ? ? We can detect the A +, A-voltage. Normal voltage should be around 25V. When a group is detected when the voltage is only 16V or so (less than 18V AC input voltage), estimated the corresponding filter capacitor has failed. For example, A + is only 16V, then C1 has failed, lost filter effect, substitution with the same size capacitor can. .
Rectifying tube judgment is also relatively simple, universal table of ohm, measurement diodes forward and backward resistance, you can quickly determine the diode is good or bad. Specific methods for lack of space between repeat here.
3. Amplifier chip damage caused hum. Such as: light cavalry V23SE, when not playing music, a great "buzz" sound. Unplug the input signal even if the line will turn it down dead, buzzing still great, still can not be removed. The most likely fault location is LM1875T chip itself is damaged, causing the output 4 pin DC voltage, so that the speaker issued a dull "Om" sound, simply replace the amplifier chip can solve the problem. .
LM1875T is relatively easy to damage the device, apart from signal injection. We also can use the following method to quickly determine the quality of 1875-our first test whether the normal power supply of the chip, which is 5 feet, 25V 3 foot 25V is negative. In the absence of signal input, three feet should be zero voltage. If the measured 4 feet (amplifier output) of the DC voltage output, (or even 25V or so), determine the chip has been corrupted. Particular point to note: TDA2030A (LM1875) 3 and heat the pin contact surface is connected, if the cooling plate surface and the heat insulation between the pieces do not mat, maintenance must bear in mind: Do not touch the ground plate heat or power line Otherwise, may lead to chip damage. .
4. (a normal satellite box playing music), and a subwoofer without playing music with great sound "Weng Weng". Even if you disable the input signal line, the volume dies, Weng Weng still great, always impossible to erase. This phenomenon is the bass channel general phenomenon of circuit failure, most likely is TDA2030A chip damage. TDA2030 4 feet caused the output DC voltage, so that the Horn boring "Ong" sound, simply replace the power amplifier chip can solve the problem.
5. 2.1 speakers (see R201T circuit) the satellites to normal when the subwoofer speaker is only just getting a little hum, hum a few minutes more and more, the BASS sound no volume to minimum of (master volume adjustments have no impact on the hum). Analysis: subwoofer bass drone can be adjusted by the control potentiometer BASS, bass amplifier TDA2030 normal preliminary determination.Scope should be at the pre-amplifier or low-pass filter, the most likely is the predecessor chip RC4558 performance causing noise, after (the ratio of R17 R18/) 6 times magnification, entered the subwoofer amplifier, revert to the annoying buzzing noise. Replace the amplifier chips that can solve the problem.
Edifier R Series 2. .1 Speaker works with the rapid repair methods (with photos). .
Recently looked at the latest by 2005 the electronic newspaper "consolidated discovered a cruiser R201T principle drawings. This drawing is Nanjing Liu Mr. According to circuit board in-kind Huaiyu portrayed. Because the original authors simply describes how R201T parameters and does not have a job to do a detailed introduction to the principles. Here, I would like to use this reference to the drawings. On the Cruiser R201T principle of a job to do, and doing a few practical repair methods, this article is also applicable for enthusiasts.
Works such as drawings as follows: divided into three parts. Power circuit, respectively, the satellites amplifier, bass circuit. .
??? ? ? power circuit (the bottom part of the drawing): after the fuse 220V (F), and after entering the switch S, transformers transformer primary secondary output dual 12V AC, dual 12V fed by VD1 composition of bridge rectifier circuit circuit, after bridge rectifier and C14, C15 (3300UF/25V) filter, the output voltage is approximately plus or minus 16V (U = 1. .414 * 12V), i.e. A + to A-16V, positive to negative 16V. Positive and negative 16V for three power amplifier chip delivers power, UTC2030 TDA2030. Another way through R21, R22, after the step-down from B +, B-output of about plus or minus 12V to bass preamplifier and low-pass filter IC4 provides the supply voltage. .
In this paper, power preamplifier and did not use 78/7912 three-terminal regulator, mill operators replace two, capacitance 3300UF may also consider joining LM7812/7912 to lead a more stable operating voltage.
2, left and right channel amplifier (the satellites amplifier circuit), left and right channels as a result of exactly the same principle. Here I am only drawing the right channel, for example, for a description. Figure: RIN for the signal input through coupling capacitor C23 into the volume potentiometer (volume potentiometer by three pins, and the C23 is connected to the input, output, also called sliding side, the other pin to ground terminal ), adjust the volume of the signal into the composition of the treble by the R1/C3 improve circuit that can improve a certain amount of high frequency signal to the sound clearer.C1/R3 circuit, consisting of high-pass filter cutoff frequency is approximately about 200HZ; signal coupling capacitor C1 into the left channel power amplifier, model for the 1 foot UTC2030, after power amplification, the fourth by 2030 feet output to promote satellite box. In the figure a feedback resistor R7, R9 to R7/2030 the magnification of the chip. As a result, adjust the resistance of the R7, you can adjust the magnification. R11/C7-speaker compensation network.
III subwoofer circuit. From the left and right channels through two 10K resistors R5, R6 until after the coupling capacitor C11, and later the signal into the IC4, model JRC4558 of 3 feet, the figure IC4A for the subwoofer preamplifier. R201T amplification of this amplifier is set to 6 times. (R17/R18), after pre-amplification in order to ensure a large enough voltage to obtain a large enough volume. 4558 1-foot for the front output by R19 and entered by the IC4B, C9, C10, R20 form a low pass filter.Low-pass filter is used to allow only the low frequency signals below 200HZ. R19 R20, adjustment, C9, C10 can adjust the cutoff frequency.
IC4B output after the ---- C19, and the volume potentiometer input Duanxiang connection, adjust the subwoofer volume, by the potentiometer wiper outputs into the subwoofer amplifier circuit IC3; TDA2030A, this amplifier circuit consistent with the principles and the satellites . 4 pin to output, to promote the subwoofer sound. .
The above is the basic working principle R201T. in passing that in the figure a Department ID is wrong: that is, the 1 foot TDA2030A input should be marked as "+," namely, the phase ends. Drawings of 1, 2, foot sign out.
Note: Edifier R1900TII, 1800TII. . Light Cavalry V23SE, Swans M200, M20W, M20L T120. . In the use of the chip LM1875T. . It works the same with this article TDA2030A. . (TDA2040, TDA2050 principle above). .
2. maintenance method: .1 speaker.
Grasp the basic principles of the circuit, the multiplier of the maintenance. In fact, doctors see patients as maintenance of sound, like, pay attention to, "look, smell, questioning." .
Maintenance before doing: audio experiences a failure, do not hurry to start. To ask the user to use:-after a failure, is there anything abnormal sound, such as "UC card" noise, there is no smell the smell, the smoke with or without sound, see, so you can quickly understand the status of the sound. Experience sound silent or Mono etc, dont judge faults for reproducing itself; rather, it is first necessary to troubleshoot signal source and the connector. Such as check the status of the computer is placed on mute the system volume is not transferred to the smallest seat? ? ? ? Balance control is in the middle position? ? ? ? Determine the sound card or DVD / CD signal no problem, also check the output of the audio cable, and sometimes, the connection line contact will cause no amount of mono or a noise. Another. The satellites have to check the wiring clip, with or without loose and so on. (Sometimes you can swap the two the satellites to determine the satellites and the amplifier circuit is good or bad); determine the signal source and connecting cable, no problem, have not ruled out a failure, before deciding to repair your speaker disassembly. .
After opening the host box, use the "direct observation of"--------.
Seeing whether the apparent burn ------ elements, burning black, burst traces, filter capacitor or without obvious "bubble" phenomena. .
Nose to smell------the smell associated with no Coke smells like transformers have no obvious cinders.
Hand touch ------- touch are all related devices have a normal temperature (such as individual rectifier is very hot, probably tube breakdown.). .
Ear------turned has no sound strange. For example, some poor quality voice transformer itself will be issued zooming "acoustic", resulting in the sound quality deterioration.
The following example describes in R201T speakers of several common troubleshooting methods:. .
1. power on the system without any response, satellites and subwoofer are not audible. (Two volume adjustment potentiometers are no response). This fault is basically considered to be a power failure. (Because three amplifier chip at a very low probability of damage). Multimedia stereo fuse if installed outside. We can loosen insurance cover, remove the fuse, observation: If insurance is solubility broken, do not hurry to put on the new insurance. We can observe in the case of damage insurance: If the fuse is intermediate or two, there are no obvious signs of burn black. It can be estimated, it is no accident damage insurance. (Because of higher utility voltage causes) then fuse with the same specifications can rule out the general substitution. (If the fuse box mounted to the host, the need to open the lid to take out insurance). .
If the fuse of the pipe wall burning darkness, it is estimated that the transformer (or condition), rectification or filter circuit components in the circuit may result in this behavior. Then we can watch Transformers has no smell, look for any signs of damage. At the same time you can check the universal table without secondary output voltage. If the transformer output correctly, they will examine four rectifiers are no breakdown short circuit, overload capacity, and so on. Until the identified short circuit components.
Second, mono. For example, the left channel mute, I can remove the door of the satellites the left channel, right channel access to the satellites. At this point, if the satellites sound, you can confirm cause of the malfunction of the satellites for the left channel speaker faulty or burned. If the case then the right protection, fault still shows a good speaker, but the left channel amplifier circuit is damaged. (Also can R201T: behind the left and right channel audio input RCA connectors swap to determine 2. .1 Speaker's job status, if the left channel to speak out, there may be sound card interface, or sound card ---- poor contact -R201T cable problem in itself lead to a single channel).So, how to repair the left channel of the amplifier circuit?????, we look at the drawings, diagrams I marked a, b, C, D, E, a few "key points". IC2 is the left channel amplifier circuit, we can use a simple and effective "injecting" (also known as signal interference method), you can use medical metal tweezers or other small screwdriver (hand touch the metal parts), direct touch point b on the diagram. The power amplifier chip 1 feet, at which point the speaker should be larger "Titicaca", if not, then basically you can judge the power amplifier chip is already OVER. We use the same model of the chip replaced. . UTC2030 can UTC2030, TDA2030, TDA2030A direct substitution. Also be noted, TDA2030A inverting input of the R10 and C6 disconnected or damaged, may cause obstruction or even a silent voice. In addition, A --- B points are caused by circuit board copper foil off the left channel will be silent. Maintenance is the premise of the above methods: IC2 operating voltage under normal circumstances. (That is 3 feet for the negative 16V, 5 feet is positive 16V or so). .
Introduction to signal interference method two: you can use the universal table of resistance. (Generally consists of R * R * 1, 10, 100, R * R * R * 1K, 10K) stalls.
The two tables document, a ground, the other as a signal into the probe. The key points of the signal interference, speakers should be "flap" sound. Where R * 1 file strongest interference signal. Maintenance staff can choose according to the specific situation of different signal intensity. .
3. no sound from the subwoofer. We can direct universal table of R * 1 bombarda retaining measurement, speaker should have smaller "UC card", otherwise the loudspeaker has been corrupted. Horn in normal circumstances, we still use signal injection method, in order to quickly find the point of failure, usually from the "after"-interferes with the "before". When the amplifier level before signal injection, there is no fault, and forward into the signal level.
If the drawings: In the F point into the interference signal, the bass speaker should have "flap" or we need to overhaul TDA2030 amplifier circuit. If the flap normal, but the subwoofer does not work, we can check the bass volume potentiometer, exclude potentiometer problems, not solve the problem, it has to check IC4. IC4 has two roles, one preamplifier, a low pass filter. If IC4 power or their damage is not normal, it will cause a silent failure subwoofer. (Note, IC4 is an 8 pin 12V, 4 feet for the negative 12V).Before carrying out such checks, we want to make visual look, there is no fault, and circuit board components have no obvious Burnout phenomenon. This can detours.
Quick Judgement:. .
TDA2030A is relatively easy to damage the device, apart from signal injection. We also can use the following method to quickly judge the 2030 is good or bad-we detect whether the normal power supply of the chip, which is 5 feet, 3 foot 16V is negative 16V. In the absence of signal input, three feet should be zero voltage. If the measured 4 feet (amplifier output) of the DC voltage output, (or even 16V or so), determine the chip has been corrupted. Particular point to note: TDA2030A (LM1875) 3 and heat the pin contact surface is connected, if the cooling plate surface and the heat insulation between the pieces do not mat, maintenance must bear in mind: Do not touch the ground plate heat or power line Otherwise, may lead to chip damage. .
4. adjust the potentiometer, the speaker has Kaka noises. This failure can be used in WD-40. Reference: http://www. .edifier. .com/cgi-bin/bbs/bbs. .cgi? u = bbs&id = 20040216225824sb wear, and specs potentiometer substitution.
5 speaker, the "whistle" sound, or more noise. When a rectifier diode rectifier circuit breakdown, or the filter capacitor failure. May cause this failure. How to determine whether the failure of filter capacitor do? ? ? ? We can detect the A +, A-voltage. Normal voltage should be around 15V. When the detected voltage of a group of only about 10V, the estimated corresponding filter capacitor has failed. For example, A + is only 10V, then the C14 has failed and lost pass through. Substitution can be used with standard capacitors. .
VI. (normal playing music satellite box), and a subwoofer without playing music with great sound "Weng Weng". Even if you disable the input signal line, the volume dies, Weng Weng still great, always impossible to erase. This phenomenon is the bass channel general phenomenon of circuit failure, most likely is TDA2030A chip damage. TDA2030 4 feet caused the output DC voltage, so that the Horn boring "Ong" sound, simply replace the power amplifier chip can solve the problem.
Picture. .
On the identity of the chip.
See 3 pictures, we can quickly identify NE5532, and the TDA2030A pin order. Wallpapers 1: The RBI's for the NE5532 (JRC4558) pin 1 pin. The picture shows the dual op amp the most under the identity of each pin. At a glance. .
NE5532 (JRC4558) pin-out: 1 the output for power amplifier, 2 inputs for RP, enter 3 feet. 5 feet for another operational phase, 6 foot 7 reversed-phase input, the output pin. 4 feet is negative voltage, positive voltage 8 feet.
The middle of the picture in kind for the 2.1 speakers commonly used TDA2030A amplifier chip, this chip for dual in-line package. --- From the right from the left: close to the cooling plate for 2,4 feet. Front row were the first 1,3,5 feet. (LM1875 pin exactly). .
