TABLE OF CONTENTS 1 Overview DS186 1.1 About DS186 Phone 1.2 Distribution of the mainboard components 2 RF 2.1 RF Overview 2.2 Transmit 2.3 Receive 2.4 Common RF Malfunction 3 Baseband 3.1 Baseband Overview 3.2 Logic 3.3 Power management 3.4 Baseband common malfunction 4 Reference for maintenance 4.1 No power on...
1 Overview DS186 1.1 About DS186 Phone DS186 mainboard is based on the MTK platform designed to support 2- band which supporting the FM and Bluetooth calls and transmission, the mainboard system consists of the base-band (CPU: MT6253+TY6701111184KC) and the RF (MT6253+SKY77518).
2 RF 2.1 RF Overview RF part mainly consists of transceiver MT6253 (adopts program of near-zero IF receiver, supporting the EGSM / DCS and 26M VCTCXO as the clock input, integrated clock buffer, LO VCO and TX VCO and regulator, only need for external connections of VBAT / AVDD), SKY77518 (it supports EGSM / DCS and integrated automatic power control and transceiver switch).
2.2 Transmit TX is composed of the modulation loop, power amplifier and antenna switch. PLL is mainly in the internal MT6253, I / Q signal first enters into the MT6253, after entering the PLL the signal is modulated to RF, and then it outputs from the chip to PA, converts into electromagnetic energy through antenna by the antenna switch after enlarged.
3 Baseband 3.1 Baseband Overview DS186 Baseband consists of CPU MT6253 and Program Memory. MT6253 baseband, the core device of the mainboard, is responsible for the normal work among various parts of mainboard, such as voice processing, image processing, power management as well as MS communications.
3.2 Logic Logic part is composed of MTK base-band management chip MT6253, power management chip MT6253 and Nor Flash. CPU : MT6253 Nor Flash:TY6701111184KC PMU : MT6253 3.3 Power management Power management consists of the charging circuit integrated in MT6253 and the external charging circuit.
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Boot process: The normal boot is to press boot key which is that the PWRKEY is being dragged down. Once the boot key is pressed, all LDO are open except VSIM. After VCORE opening RESET timer and timer out, RESET is being pitched up to start the digital baseband chip, that is, UMT6253 starts to run and roll polling its ROWX pin, pitch up its PWRONIN pin, then you can release the boot key.
3.4 Baseband common malfunction 3.4.1 Nor Flash programming does not download Data lines used for downloading software: VBAT, TX, RX, GND, CHARGE. It is mostly due to the false solder and wire bonding. First check whether the serial port of PC and cell phone is unrestricted, if not, it is caused by being lack of devices or empty solder of power manager, USB-con and peripheral resistance.
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3.4.2 Detection and Maintenance Flow Chart of No download malfunction...
4 Reference for maintenance 4.1 No power on No power on Check whether the battery voltage is Charge the battery higher than 3.4V Check whether the battery and the key pad is Wipe off the thing oxidized or there is or clean the key pad anything else on it Check whether the...
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Check whether R4401,R1107 is Change R4401,R1107 broken C1119:1.8V C1119:2.8V, C1120:2.8V, C1121:2.8V, C1122:2.8V, Connect with the battery, Replace the earthed capacitor C1123:2.8V, press “ON” key, check corresponding to the ChangeU1100 whether the output voltage defective pin, Check whether of U1100 is normal it is OK Check whether the output ChangeX1100,...
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Check whether the output voltage Change U2602 Change U2605 of U2602 pin 3 is 0.5V around Change the Flash (U1101), Change U1101 check whether it is OK ChangeU1100...
4.2 Shut off automatically Shut off automatically D/L the latest software, Check whether it is OK Replace with a good battery, Check Change the battery whether the primary cell is broken Check whether the rubber, used to fix the Reassemble the battery, is lost or at the rubber other location...
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Check whether the contact of Reassemble the dome the key PAD & the dome is OK Check whether X1100 ChangeX1100, output frequency is C1113,C1114 32.768K exactly Refer to the maintenance method of ‘No power on’...
4.3 Dead halt Dead halt D/L the latest software, Check whether it is OK Replace with a good battery, Check whether Change the battery the primary cell is broken Check whether the Clean the K/B, problem is resulted reassemble or change from ‘KEY NG’...
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Check whether the ChangeX1100, output frequency of C1113,C1114 X1100 is 32.768 exactly Check whether the contact of Reassemble the key PAD & the dome is OK the dome Replacing with the programming FLASH, check whether it is OK Refer to the servicing method of ‘No power on’...
4.4 No charge No charge Replace with a good adaptor, Check Change the adaptor whether the primary adaptor is broken Replace with a good battery, Check Change the battery whether the primary cell is broken Check whether the Clean or battery connector ‘J9410’...
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Change B1103 Plug in, Check whether it has an BLM18EG221TN1 voltage of 5V on B1103 Check whether there is broken of Change the defective U1102, R1105,C1131, Z1340 ChangeU1100...
4.5 Quantity of electricity faulty detection Quantity of electricity faulty detection Replace with a good battery, Check whether the primary cell Change the battery is broken Format and Download the latest Software, then calibrate the Check whether there is broken Change the defective of D1300 ChangeU1100...
4.6 No display No display Download the latest Software, Check whether it is OK Check whether the LCD is Re-weld or change the weakly welded or broken ChangeU1100...
4.7 LED NG (on the LCD) LED NG (LCD) Check whether the Change the LCD LCD is broken When normally backlighting, check Change U4400 whether the voltage of U4400 pin2 is at the high level Check whether R4400 Change R4400 is broken ChangeU1100...
4.8 LED NG (on the key board) LED NG (key) Check whether there Checking method: Clean or wipe off is anything (or Mylar) Crosstesting the thing the two sides of on the key LED by Multimeter , gearing to the short circuit, if the LED is on at one direction, it shows good Check whether the...
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Check whether the Reassemble or Charge connection of sliding PCB & the sliding FPC MB is OK Check whether Check R4409 C4490 R4409 C4490 C4491 C4491 is broken Check U1100...
4.9 Key NG Key NG Check whether there is anything oxidized or cleaning the key pad smudge on the key pad Check whether the Change the metal dome is oxidized metal dome or broken Check whether the Reassemble or Charge connection of KEY PCB &...
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Check whether the ED4401 ED4402, Change the defective D4417~4420 D4410~4412 is broken Change CPU(U1100)
4.10 No ring No ring Checking method testing D/L the latest edition, the resistance of the SPK Check whether it is OK by Multimeter, gearing to the resistance, the resistance of it is 8ohm normally Check whether the Re-weld or SPK is void-welded change the SPK or broken...
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Check whether the voltage at U3310 pinC2 is Change U3310 at the high level Check whether Change R3311 R3311(100K) is broken Change the CPU...
4.11 No receiving voice No receiving voice D/L the latest edition, Checking method testing Check whether it is OK the resistance of the REC by multimeter, gearing to the resistance, the resistance of it is 30ohm around Check whether the Clean or REC PAD is oxidized Change the REC...
4.12 No sending voice or the voice is small No sending voice or a small voice D/L the latest edition, Check whether it is Check whether the MIC Reassemble or change Checking method rubber is broken or the MIC rubber testing the resistance of displacement the MIC by multimeter,...
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check whether there is anyone broken of C3308~3312, Change the defective B3300, B3301,D3301, D3302 Change the CPU...
4.13 No vibration No vibration D/L the latest edition, Check whether it is OK Check whether the Reassemble Checking method testing motor is locked by the motor the resistance of the motor displacement by multimeter, gearing to the resistance, the resistance of it is 22ohm in general Check whether the...
4.14 SIM Card inefficacy SIM Card inefficacy D/L the latest edition, check whether it is OK Check whether the SIM Change the SIM card card is broken Check whether the SIM Card Connector J9420 Change the defective is broken Check whether there is Change the defective anyone broken of C4423 C4424 D4421-D4426...
4.15 TF card inefficacy TF NG D/L the latest edition, check whether it is OK Check whether the socket ‘J9420’ is Re-weld or Change J9420 void-welded or broken Check whether there is anyone broken of C4433 Change the defective C4434 Change the CPU...
4.16 Camera inefficacy Camera NG Check whether the connection Reassemble the FPC of J9401 & Camera is OK Check whether the Change the Camera camera is broken Check whether J9401 Check whether C4410~4415, Change pin5 has an voltage of C4420 are voidwelded or broken the defective 2.8V,pin3 has 1.5V Check whether...
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4.17 Bluetooth circuit(MT6612) Bluetooth is a design feature of this cellphone. It is with a matching Bluetooth headset and the phone has a container which can charge up Bluetooth headset through the main board, to accommodate Bluetooth headset. Some of the projects may not have this function, however, the mainboard is compatible.
4.17 Bluetooth inefficacy BT NG D/L the latest edition, check whether it is OK Check whether the Reassemble the BT antenna is antenna touched well Check whether C5307 is void-welded Change C5307 or broken Check whether U5301, Change C5300 are voidwelded or broken the defective...
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Change U5300 Enable the BT function, Check whether check whether C5302 the voltage at R5301 Change CPU has a voltage of 2.8V, is the high level C5305 has 1.2V Check whether C5301 has an output Change C5301, C2637 frequency of 26M Change U5300, check whether it is OK Change the CPU...
4.18 Earphone inefficacy Earphone inefficacy Check whether the Change the earphone earphone is broken D/L the latest edition, check whether it is OK Check whether the earphone Change J9432 connector ‘J9432’ is broken After inserting the earphone, Check Change R3300(1K), whether the voltage at C3319, B3305 R3300 is 0V around...
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No sending voice of No receiving voice of the the earphone MIC earphone receiver Check whether there is anyone Check whether there is anyone Change the defective broken of C3300~C3304, R3301- broken of R3300, R3309 R3310, Change the defective R3303, B3306, C3351, C3320 C3316~3319, B3304, B3305 Change the CPU U1100...
4.19 FM inefficacy FM NG D/L the latest edition, Check whether it is OK Enable FM function, check whether C5311 Change C5311, C5312, C5315 has a voltage of VBAT, C5312 has a voltage of 2.8V check whether there is anyone broken of C5309, Change the defective C5401, B5401...
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Check whether the output frequency of Change C5310 C5310 is 32.768K check whether there is anyone broken of C5313, Change the defective C5314 Change U5303 Change the...
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