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 (2 x 12V to radicals), 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 left 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.Then 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 amputated 200HZ low frequency signals below, R20 and C10 decided to cutoff frequency. (Specific to each manufacturer's cutoff frequency settings are slightly different). After the IC4B output-C19, and volume potentiometer input connected, adjust the subwoofer's volume by sliding end output into the potentiometer and the subwoofer amplifier IC3; TDA2030A, this circuit principle and consistent satellite box amplifier. 4 feet to output sound, Bass trumpet.
Above the basic working principle for the R201T. . Way that has a logo image above is wrong: the TDA2030A pin input 1 should be marked as "+" or with similar input. Drawing against the standard of 1,2 feet. .
Note: Cruiser R1900TII, 1800TII. hussard V23SE, M200, M20W hivi, M20L T120. in chip LM1875T. it works as described in this document are consistent TDA2030A.
2. .1 Speaker repair method:. .
Master the fundamentals of electric circuit, the repair will do more with less. In fact, overhaul sound like doctor, pay attention to the "look, smell, and asked,"..
Maintenance to be done before things: sound experience failure, do not hurry to start with. First ask the user: The failure of the before and after any unusual sound, such as whether the "Kaka" The noise, smell or without smell, with or without sound to see smoke and so on, so you can quickly understand the sound state. Silence or mono sound experience such failures, and do not rush to judge the fault for the sound itself; and the first signal source and the first rule out cable problems.For example, check the PC over the mute State of the system volume is not transferred to the smallest position???? balance control is located in the middle position???? determined the sound card or DVD/CD signal no problem, check the output of audio connectors, sometimes, the amount of contact connector does not cause mono or noise. In addition. Satellite box wiring clamp should also check that there are no loose. (Sometimes it can take two satellite box transposes to determine the satellite box and power amplifier circuit is good or bad); determine the signal source and the connector without problems, yet when troubleshooting before disassembling your speaker to repair it.
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 then the right-the satellites malfunction persists, note speaker is good, but the left channel amplifier circuit is damaged. (Also can R201T behind the left and right channel audio input line to determine the swap 2. .1 Speaker working condition). How, then, the left channel of the amplifier circuit repair it? ? ? ? ? We take a look at the drawings, the figure I have marked the A, B, C, D, E, several "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 UTC2030, can be used to direct substitution TDA2030A TDA2030. 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). .
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"----"before" all rows. The power amplifier line after the class is first made, no fault signal injection would then forward level injection signal.
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.
Continued on, TDA2030A is relatively easy to damage the device, in addition to the signal injection method. We can also quickly determine the following way ----- 2030 The quality of our first test chip, the power supply is normal, that is 5 feet is positive 16V, 3-pin negative 16V. In the case of no signal input, while three-pin voltage should be zero. If the measured 4 feet (amplifier output) with DC voltage output, (even up to 16V or so) to determine the chip has been damaged.Special needs attention: TDA2030A (LM1875) pin 3 and thermal interface is connected, if the heat surface and heat insulation film between no mat, repair to remember: do not touch the ground heat or power, or they may cause damage to the chips.
Fourth, adjust the potentiometer, the speakers have Kaka in the noise. This failure can be WD - 40 cleaning. References: http://www. . Edifier. .com / cgi-bin / bbs / bbs. . Cgi? U = bbs & id = 20040216225824sb serious wear, with the same specifications potentiometer substitution. .
(5), trumpet, "howl" sound or a considerable amount of noise. When the rectifier circuit a rectifier diode breakdown short circuit, or filter capacitor failure. May cause this failure. How to judge whether the filter capacitor failure???? we can detect A +, A-voltage. Normal voltage should be around 15V. When detected, only a select group of voltage 10V, estimate the appropriate filter capacitor. For example, only A + 10V, C14 had expired, lost its role filtering. Used with the specifications of capacitance substitution.
6, subwoofer does not play music in a great time, "Weng Weng" sound. Even if the input signal lines pulled, Weng Weng still great, has never been able to eliminate. This phenomenon is generally the phenomenon of channel bass circuit fault caused the most damage possible is the TDA2030A chip. 4 feet caused TDA2030 DC output voltage, so that the speaker issued a dull "Weng" sound, simply replace the amplifier chip can solve the problem. .
See reply to 5 in the third picture, we can quickly identify NE5532 TDA2030A pins, and order. Plates 1-dotted with in as NE5532 (JRC4558) pin 1 foot. The following figure to all pins of the operational amplifier-identification. At a glance.
NE5532 (JRC4558) pin: 1 to op amp output, 2 for the inverting input, 3 pin input. . 5 feet of another op amp inverting input, inverting input 6 feet, 7 feet out. . 4 feet for the negative voltage, 8-pin positive voltage. .
Common TDA2030A amplifier chip for SIMM package. Left-right: 1, 2, 3, 4, 5 feet. (LM1875 pins are exactly the same).
