手机开机后定屏白屏)（The phone is switched on and the screen is white.）

手机开机后定屏白屏)（The phone is switched on and the screen is white.） 手机开机后定屏白屏)(The phone is switched on and the screen is white.) The maintenance method of the screen white screen and fixed screen green screen after the mt phone is turned on The 2010-06-17 and The maintenance method of screen black screen and black screen is determined after the mobile phone is turned on 1 boot not maintain maintenance First to see if the power 6305 33 feet 2.8 maintain voltage, if you have it in the power supply, if not the CPU to tear open come down to see the power of 33 feet CPUC3 have foot bolt... And you can't exclude software... 2. If a MT cell phone is just a CPU bad morning, it can be determined that there is a difference between 32.768 points 3 -- CPU6218, power supply 6305 -- 4. The following voltage is not turned on, and the 7 feet of the power supply to B + have a 0 o resistance, and the short answer is OK. It's near the power supply The 4MT cell phone does not recognize the card 100% of the power supply of 8 and 27 5 the MTK.. Hear echo spreadtrum. Make a phone call to each other, kill a call each other hear echo, - many new, maintenance train of thought as follows, 1. When take off the receiver. Echo, 2. JingJian space turns out to be two of the receiver loop inductance, inductance is low. (location: and the receiver first black series inductance, one on each side. Remember not grounding the) 3. Solve, to remove them directly, instead of the resistance of the 18 to 25, too little resistance will have echo, too large the receiver will be in a low voice. 6305 power supply machine for MTK series. Because its platform is general and special, the screen light is not bright can be repaired this way. Whether or not the original machine is in parallel or in series, it is changed to parallel, and then the anode is connected to b +, and the negative pole is connected to the power of IC41 #. You can fix all the MTK screen lights. The principle is that 6305 is a screen light that signals the signal, and B + goes by the light to the 41st of 6305. When the lamp is out, it has a high level of 2.8. The result is that the voltage is not enough to light the lamp. When the light is on, the light is low and the light is on. Through my experiment. One hundred percent is accurate. I hope I can help you 7 MTK - unrecharged Each MT board has a charging 5 Angle tube, and it is a protective class of MT. You can take it off 100 percent So you just add 5 volts to the power supply and you don't believe it 8 MTK does not boot up than kill See if there is a boot current, there is no check line, and see if the boot key is blocking the ground 9 MTK plugs a card to turn off, do not insert card is ok, generally is software cause 10 MTK charge a few minutes display screen prompt "warning, charger contact bad" malfunction, non-charger problem, machine board failure, wang2 jing. 1: first, the problem is not the charger. (it is not possible that the original charger will fail, because the charging current or voltage is problematic.) 2: not CPU problems... The failure of CPU virtual welding has been removed for automatic charging or charger connection 3: it should be the voltage or current that is detected to be charged. Replace the row resistance 104 OK. 104 exclusion can appear bad low voltage, automatic shutdown, charging a few minutes to display screen prompts "warning, charger poor contact, is it too, and I experience obtained more maintenance machine good,,,, I,, 11 MTK delivers a small yet another discovery The MTK series of MTK series machine found that the message is small, close to silent, replanting the CPU is ok! Try several! 12 MTK small current does not turn on must kill The MTK small current is not turned on, the original has no maintenance record to change the CPU, the word library has no fruit, and the end adds the end plug ok 13 MTK chip power supply 6305 water no current response required kill power 6305. There is a 0 ohm resistance next to it, remove, short answer, OK 14 MTK chip lamp after the white screen - maintenance experience Once the store's warranty machine with no signal, after repair, show it to the customer when found after the lights went out, press the button, there is a light but no show, thought it was hot to the CPU (CPU6226BA), will it and character reshipment, reshipment is still the same problem, after I hand and no information! Asked several other teacher, some say it's display, others say display power diode (is white during startup, before after the lights went out, according to the opposite problem in the problem of the display power diode OK) think it's the same problem, but still won't do, originally want to change the screen, the result I want to try it try fluky psychology recovery factory, heavy boot for the first time to OK, but can't again the second time, then I take out the card, then back to factory, and then pack card factory once again OK, then try out a few is OK, there is such a problem also yesterday, the same method done... 15 MTK signals must be killed I give others take a lot of MTK chip machine, outside what is normal, entered and there is no network, sometimes also appear emergency call, I think everybody is met, I took a half a month of amplifiers, antenna switch, intermediate frequency, even in the CPU, or repair bad, then I got a machine and it is the same, compare, yifan is studied carefully, there is one thing not changed in, filter, I will take down filter change. Day ah /? To normal. I didn't realize that I had been working on it for so many days. It had been a lot before it had been repaired and returned to the customer. Now I know that I can't leave a small piece in the repair. Now I've fixed more than 10. For reference only, there are other quick fix methods, 16 MTK signal maintenance method Maintenance MTK phone no signal, actually very simple. I have found that nearly time to have a lot of MTK phone no signal, and I found a bunch of people are bad, good few said. MTK no signal maintenance The first step; If there is no baseband on the side of the oscilloscope, if there is no baseband, then it is a problem in the front end of the medium frequency, usually the filter is damaged. If there is a baseband, I find that % 90 is not CPU bad, but clock crystal 26 Megabyte damage, I gave a lot of repair to my colleague. It is 100 yuan one! 17MTK USES the battery not to turn on, and USES the external power source to power up the maintenance method MTK use batteries don't boot, use external power supply can boot repair method, we can find the VBAT is electric contact B + through the power of that a few feet: such as # 7 # # 19 and 26 # 47 they and 32 # on line in the middle of a resistor, 32 # for the whole boot maintain line of the CPU, so we will be the resistance part short answer would definitely this kind of problem, principle I not much said, you give it a try. (resistance) on the edge of the power supply must be top ha!!!!!! 18 MTK is the latest to find out that it may be useful to you The memory card also causes the key 220ma milliampere current to be switched on Today to receive a branded machine the MTK chip customer said battery with less than an hour, there is no electricity, I press the power button 220 ma electric a try It is no wonder that in less than an hour I will offer teardown Remove the memory card Charging a try the normal install memory card failure remains I was secretly to help him change the memory card Ha ha is so easy to receive money The machine of MT, the signal full, can't find the net, 3166 amplifier, not the amplifier problem, OK! The machine of 19MT, the signal full, can't find the net, 3166 amplifier, not the amplifier problem, OK! Today after a less known and inferior brand machine, the signal is full, no network, power amplifier, 3166 6226 CPU, call 112 commissioning ` ` no emission current, so the power amplifier demolition, sub ` ` ` ` no ` ` ` ` study for a while, open antenna frame, found that the antenna attached to have two little guys gone below the contact point, hence with lightning speed short sub, commissioning ` ` ` OK ` ` ` ` back to power amplifier, 80 oceans got ` ` ` ` ` ` which ace can parse, why the two capacitance resistance can affect the launch 20 MT water can't be turned on When the MT series (power supply 6305) is in the water, press the startup button without the current (no broken line on the boot button! If the broken line starts from power 32 # fly line straight on the positive pole), the battery interface + extreme fly line to the power supply 6305 is 47 # I have fixed the N department. I hope I can share it with you 21 MT depends on current repair 1. The power-on current is only 10-30 milliampere back to zero. It is generally a software problem. If writing software is not good, most of it is CPU virtual welding. 2. Start at 20-50 mah jitter and write the software normally. Start at 30 milliamps, and then write the software back to zero. Turn on 30 milliampere to return zero, usually a clock crystal bad 22 MT phone has a headphone mode that must be killed MT phones have headphone mode. First, measure every foot of the headphone jack. If there is a voltage of 2.2 to 2.8 volts, it will be directly grounded 23 MT chip "no service" maintenance method! No service, no network, now the general disease of MT chip! Check launch, receive, CPU, power IC, antenna switch, amplifier, filter, launch VCO, intermediate frequency... Have all been done or not, how to do? No maintenance ideas! It is also fruitless to hand over to the master, and the machine is ready to be returned to the customer, used to press * # 06 #. Is it a software problem? Regardless, the FLASH to be removed, access to the Internet to find a data write, put CARDS on a try, OK. Later also to a lot of MT chip machine, appeared no service and no network, I'll look at the string of Numbers, normal, you can check the mainboard, a normal is not written material, almost all repair, MT now... Published here, is that I wish to refer to you, little take unnecessary detours, in less time to earn more money, if you have any of the new published maintenance method can refer to everyone! 23 MT chip keys failed and found again Today, a CECT 388 pasted double bond is hand-written by hand. MT6225A. The failure of the key is broken, and it cannot be turned off Commissioning at the moment of turning can be according to the following keys. Teardown traces a look brand-new didn't fell into the water, are former reinstall the CPU directly, but this time with the same fault, manual fine. Write information failure is still the same again, and finally even the power MT6305 changed. Wise men after customers. Say if accidentally pressed once, then remove the touch screen of commissioning OK, turns out to be this glass is doing strange. There is a touch screen failure would cause button downs, buttons and downs first check whether the touch screen with a protective film. Protective film quality can also cause this failure, insert tail part of the problem will appear button failure, this is the wrong with 6225 I met many, many are caused by the touch screen Especially in 6225 I have taken a gionee V3200 is changed in this problem is OK The 24 MT chip has a low power power and automatic shutdown - no change of the R104 resistance emergency maintenance method. It is known that the MT chip is prone to the failure of the battery power to automatically shutdown This kind of failure is usually the cause of the battery test resistance R104 and himself in the process of maintenance is difficult to get the R104 (general groups are not universal), for emergency, I try to remove R104, stabilized voltage supply of commissioning troubleshooting, failure remains after install batteries, inspiration came, so disconnect the battery detection of foot and the main section, the problem with the battery, battery testing is OK This method is aimed at the 3-pin MT cell phone for the battery contact All 25 MT is unsound The MT series listen to the unsound motherboard problem with no voltage at the end of the receiver 26. No money, the A612. A635. A615 series shows the white screen. The screen must be used to kill and kill. Please reply to the series A612. A635. A615 and other series of white screen. The screen must kill It's good to ask you to reply to the previous question 28 changhong M868 boot 3 seconds key failure must kill changhong M868 no phase-change key is not psionic hahaha remember to top me 29 national production machine water key malfunction must kill!! I have already tried the failure of the domestic machine in the water press 30 domestic automatic startup with a less known and inferior brand All key failure with buzzer, find the power button to ground resistance (may also be on the back of spanner, carefully looking for) pick go ok, I have taken 3 (domestic) with a less known and inferior brand You will be able to quickly judge the MTK series without any signal Use 3146 amplifier, 6219 intermediate frequency of the medium frequency of 52 feet to 900M output feet Add a long antenna here, and it can be judged that there is no signal: the cause of the middle frequency or the middle frequency In the past, the problem was 26M, the middle frequency itself. CPU In the future, the problem lies in the amplifier, the antenna switch OK How to judge MT series CPU If the voltage on the two sides is different, then most of the CPU is broken Raise calibration touch screen. Change the transmitter. The way to change the charger. 1. Now, more and more of the screen is changed, the touch screen changed or changed. Sometimes the school is not allowed to do many times, so let's start with the key 5, and see which direction is biased. In the school on time, all the center points should be tilted to which direction, after the calibration is successful, the direction of the central point will be moved a bit and calibrate, so no more than three times, basically OK! No, it's just another touch screen. 2. After many change microphone, or not to send words or sounds small, are generally two way when the transmitter of the negative ground, the positive after one of the feet, no positive answer another foot, basically can be done. Some phones have an echo, a 2-5k resistance in the positive. Now there are more and more miscellaneous CARDS, special charger is difficult to match, as long as there is the same plug can be changed. First find the tail of the anchor, cell phones, battery boot, the regulated power supply is set to 6 v, negative electrode holder to the phone cathode, anode clip, a needle on the tail plug try one by one, as long as there is charging display screen, it proved to be charging. Remember to detect the two pins of charging, find a plug the same charger, then disassemble the plug, and adjust the positive negative electrode to the corresponding leg position detected! The voice of king 898 is small. The other person can hardly hear the absolute 100%. Wang 898 has a small voice. He can hardly hear him. Use the red pen of the red pen to measure the point of the black pen of the microphone, the two parts of the microphone are connected with the transmitter, and directly weld the transmitter to 100 percent The effective way to eliminate the noise echo from the domestic machine is to connect a capacitor in parallel to the negative pole of the transmitter. Its characteristic is to direct the communication between the dc 36 retalk MT card: General speaking it is a relatively simple question, mainly check card four effective feet between the power wire, such as common 6305:8 feet of power supply, 14,15,16 IO data respectively, and the RST reset, CLK clock. One can fly line OK.. In the case of maintenance ratio, the above situation can account for 80. Other CPU is bad and the control line is very few. 37 in my maintenance experience, spreadtrum 6600 CPU models have no emission of fault signal, such as in the case of rf never move, most of them are made of CPU virtual welding, in our previous case, we will consider radio frequency fault, so the opposite, this is because the work of the power amplifier control signals are directly controlled by CPU, instead we should have a headache medicine here! I have fixed the fault for this fault. You can learn from it! Thirty-eight treat MT headphones to check the headphone jack, have two feet with 2.8, connect them. It's worth a try. 39 MT6219 chips don't boot judgment power, the CPU damage skills CPU use MT6305 MT6219, intermediate frequency MT 6129, power supply, power amplifier RF3166 models a lot, they are a common is 25 feet in the output power of 7 power supply output PMIC - master clock VTCXO 2.8 V power supply, not can press the power button to output, but can be controlled by CPU. ` CPU MT6219 master clock output 26 m the condition of the power supply control signal is: power up after pressing the power button for each CPU power supply, BI, CI feet by 32.768 KHz as start the clock of the CPU, CPU inner part work output from T1 foot VCXOEN clock circuit, the electric control signal (2.8 V) to the power supply block 31 feet, internal power supply block for start the clock of the controller open, 25 feet from the power supply output the PMIC - VTCXO voltage of 2.8 V, To U503 26 m crystal 4 feet, combined with 1 foot from the AFC automatic frequency control of voltage, CPU B4 feet to produce accurate 26 m, 29 feet after frequency division to the intermediate frequency block as intermediate frequency block the base frequency, then through intermediate frequency output to the CPU A2 piece of 31 the feet as a master clock logic circuit. So, in the maintenance CPU is MT6219 phones don't boot current are only a few ma failure, undetectable 26 m, measuring the power of 25 feet PMIC - master clock VTCXO 2.8 V power supply, if no 2.8 V, can put the other 2.8 V power supply from power supply block 31 feet, if the power supply block 25 feet can output the PMIC - master clock VTCXO 2.8 V power supply, that power supply is normal, check the CPU output T1 foot VCXOEN clock electrical control signal to the power supply block 31 feet without break or CPU virtual welding; If the power supply block 31 feet when 2.8 V voltage is connected, the power supply block 25 no master clock output PMIC - VTCXO 2.8 V power supply, and welding power source for virtual welding, no longer implants installed, or the power supply block damage! 40 MTK chip 6305 powering another found that 6305 of 32 # is boot trigger point is known to all. A diode in 32 # out its connections, if the upside or damage, will appear flashing, press the power button current even if written information is still the same. I hope it can help you. I repair a day yesterday TCL751 to outside is repaired, peer after-sales, CPU6218 character of 127 to the mainboard three had passive or new CPU chip. The chip first all do it again, current occurs after press the power button is flashing keeps flashing around 50 ma, thought it was software, write or with fault remains. After then the teacher speak, said power supply 6305 32 # connect a diode, if the upside will appear this situation, thought the mainboard has passive many times, the CPU is new reinstall again, installed after the current reflect are different, on the normal play after all. 441 MTK chipset machine common failure: the white screen fixed screen sometimes the death machine must kill to replant the CPU and the word library, even kill five machines OK 2. When making a phone call, it is connected with the transmitter positive pole and has a 2V voltage capacitor. The transmitter is directly connected to the ground Part of the 343 MT6226 part to the noise instruction is suitable for some of the 6226CPU chips of the domestic production machine, the removal of the receiver, the delivery of noise * # 3646633 # 44 MT series 3146 pa launch shutdown \ (absolute good, basic cost is zero) 3146 45 Angle is the Angle of power control, through the CPU. Can change the size of his power amplifier transmission power, so as to achieve the aim of normally launch. The specific method is to change 3146 45 Angle external earth capacitance to resistance, resistance depends, probably around 10 k, control the emission current of about 350 ~ 380 can normal use! (principle is the use of the characteristics of partial pressure resistance, pull power control voltage is low, thereby reducing the emission current of 3146, thus fundamentally solved the problem of the launch shutdown, this method also can be applied to other power amplifier circuit, the circuit is different, but the truth is the same 45 MTK series SIM card reading error changing CPU or adding cpus without power supply 46 MT series call echo fast repair slay reduce MIC gain, the MIC is negative reverse connection can ` Kill: solve the MTK series plug-in charger in a short time (battery temperature too high) must be killed: solve the MTK series plug-in charger in a short time (battery temperature is too high) Solve the MTK series plug-in charger for a short time (battery temperature is too high) Well, the original mile is very simple On the motherboard + - add a large capacitor! One can't add a ~ 6100 and a 3100 power supply of those large capacitors. The reason is that some of MTK's producers have killed MTK... Cutting corners and filtering are not good enough 48 MTK do not send word... When dialing 112, whether there are 2.8 volts or so. 2. If it is not about 2.8 volts, it will affect the dissolving of the dielectric solution that affects the sending line. 3 second yet. Check the headset line. Apricot to headphones. Call 112. Check the headphones that feet have 3 v glutaeus maximus. It directly grounded. OK. 4 above doesn't work. Then use gunning to related instructions. Restore the original data. (online). If you can't do that again, you'll have to move the chip to see if it's broken. It's two lines of the chip. It is simple and complicated to take a message. As long as the train of thought is accurate. The MT series has a solution to the problem of overcharging current in the MT series When the MT series of mobile phones were flooded, the charging current was too high to be soldered or replaced by the problem of resistance 104 50 MT6305 not reflect current solutions MT6305 power, # 4, # 7, # 19, 26 #, # 47, directly connected to the battery positive electrode, if they have one corner and battery positive electrode wire break will cause no current response, press the power button today to meet customer a fault for CECT mobile phone: boot without reflect current, switching power supply {6305} no reflection, finally found the power 7 # and battery anode break line, fly line address OK Fast judgment of MTK series no signal one of the methods to quickly determine the MTK series no signal method Using 3146 amplifier, 6219 medium frequency, the intermediate frequency of 52 feet for 900M output feet Add a long antenna here, and it can be judged that there is no signal: the cause of the middle frequency or the middle frequency In the past, the problem was 26M, the middle frequency itself. CPU If in the future, the problem lies in the amplifier, the antenna switch, etc., personal opinion, for reference 55 MTK power 6305 CPU current MTKCPU now reflect the market model, and USES 6305 MTK model of the power supply in the majority, now and you talk about the MTK phone 6305 CPU power supply current maintenance experience. CPU for MTK is known to all models of general CPU feet are close, but the chip is more durable, tend to be bad or not, but if you encounter a press the power button is 400 ma back to 0 machine immediately sure everyone will choose a first step in the CPU, but changed also cannot solve the problem is a hindrance. Power of 45 # 6305 between CPU and a capacitance (its capacitance is better check), if the capacitance is broken will appear immediately press the power button is 400 ma back to zero, or its capacitance is change into resistance is the same, more than I ever repaired this type, So suggest that we meet this situation first don't blindly in CPU, first check the power supply of 6305 to the CPU to see whether the capacitance is broken, you met this kind of models can try can generally. 556 MT6226BA's CPU full of electric white screen reset a normal maintenance method 6226BA chip with cpus full of cpus with the power to find the net writing software invalid in the case of a grid or two of the normal operation of the CPU is OK 57 with MTK platform mobile phones to send words sound small solution with MTK platform mobile phones such as: waveguide M10 M09 / M08 / D680 / D690 / M008 etc., there are words sound of small fault, found that the fault is not caused by the hardware. Can enter engineering mode repair setting value to solve, specific as follows: 1 boot [not insert card/insert card can] enter * # 3698741 # 2. Select 3 in the following menu. Audio again enters the submenu [audio] to set the value of the microphone, which is generally about 128, and the fault machine's value is smaller than that. If the set value is too small, the message will be light, and the other person will have a break. Here are some important engineering patterns: 1: * # 3698741 # Functional test: * # 889 # Software version: * # 159 # Hardware version: * # 753 # 5 motor test: * # 741 # 58MTK chip phone handset or send voice with sound wave sound to wash the motherboard of the main key words: maintenance method cell phone 91 fake