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Samsung STH-N375 Service Manual
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Samsung STH-N375 Service Manual

Samsung STH-N375 Service Manual

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SERVICE
TDMA MOBILE TELEPHONE
TDMA MOBILE
TELEPHONE
STH-N375
Manual
CONTENTS
1. Trouble Shooting
2. Electrical Parts List
3. Exploded Views and Parts List
4. Block Diagrams
5. PCB Diagrams
6. Circuit Description &
Circuit Diagrams

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Summary of Contents for Samsung STH-N375

  • Page 1 TDMA MOBILE TELEPHONE STH-N375 SERVICE Manual TDMA MOBILE TELEPHONE CONTENTS 1. Trouble Shooting 2. Electrical Parts List 3. Exploded Views and Parts List 4. Block Diagrams 5. PCB Diagrams 6. Circuit Description & Circuit Diagrams...
  • Page 2 ELECTRONICS © Samsung Electronics Co.,Ltd. May. 2002 Printed in Korea. Code No.: GH68-02790A BASIC.

  • Page 3: Baseband Section

    Need to check U110, U111, U206 VCTCXO_IN=14.4 MHz Need to check TCXO OSC302 & neighbor part VCC, ADD(0:21), DATA(0:15), FLASH_CS, SRAM_CS, UBE, MEMOEB, MEMWEB Memory (U202) control signal Need to replace Memory(U202) Program Running SAMSUNG Proprietary-Contents may change without notice...
  • Page 4 Need to check CN202-1 LCD Display Running Back lingt Running Vibrator Running Send Command Main Audio Receiver Path ON Send Command Audio tone generator ON SPK+,SPK- Signal Need to check U101_77,79 Speaker Output Replace U101 Good SAMSUNG Proprietary-Contents may change without notice...
  • Page 5 STH-N375 Trouble Shooting 1-3. Abnormal Buzzer operation START Send Command Ringer Path ON Send Command tone generator ON RINGER(U101_1) Signal OK? Need to check Q207, D201, U101 Buzzer Sound Output Replace AU201 Buzzer Operation Good SAMSUNG Proprietary-Contents may change without notice...
  • Page 6 Hock Up Ear_Mic Phone in the Jack(CN101) Send Command MIC_BIAS_EN enable Send Command AMP_EN enable HS_SENSE=H Need to check U106 neighbor parts Press Button on the Ear-Jack SEND_END=H Need to check U106 neighbor parts Ear_Mic phone Operation Good SAMSUNG Proprietary-Contents may change without notice...
  • Page 7 2. RF Section 2-1. Call processing and Online Test START Normal SVC? Check RX path Set up Call Check TX path Measure SINAD/BER Good? Check RX path Measure Tx Power Good? Check TX path DONE SAMSUNG Proprietary-Contents may change without notice...
  • Page 8 U306, C349 F303_3, U300_8 =-55dBm Need to check C324, F303 V_LNA_CELL=H F302_2=-36.0dBm U105_1=H Q102_3=H Need to check U105, Q102 Need to check U300 & neighbor parts U301_45=-39.5dBm Need to check F302 & neighbor parts SAMSUNG Proprietary-Contents may change without notice...
  • Page 9 U105 & neighbor parts Replace U301 U301_34 Lev=-28.0dBm Freq=130.05MHz Replace F301 U301_37 Lev=-13.0dBm Freq=450kHz Need to check U301, L301, C304, C306, R301 U301_25 Lev=-18.0dBm Freq=450kHz Replace F300 or Need to check R302, R303, C303 MODE TDMA AMPS SAMSUNG Proprietary-Contents may change without notice...
  • Page 10 Need to check U301 & R326, R320, C352, C127 U101_40 BBCLK= 6.2208MHz or 4.096NHz or 5.12MHz Replace U203 U101_32RX_CLK= BBCLK/2 or BBCLK/8 Replace U203 U101_31 RX_SYNC= BBCLK/32 or BBCLK/128 Replace U203 U101_31 RX_DATA= serial data Replace U203 DONE SAMSUNG Proprietary-Contents may change without notice...
  • Page 11 IF_ON=H, PON_TX=H PON_VRF3=H U101_40 BBCLK= 6.2208MHz or 4.096MHz or 5.12MHz Replace U203 U101_34 TX_CLK= BBCLK/32 or BBCLK/8 Replace U203 U101_33 TX_SYNC= BBCLK/512 or BBCLK/128 Replace U203 U101_33 TX_DATA= serial data Replace U203 TDMA AMPS MODE SAMSUNG Proprietary-Contents may change without notice...
  • Page 12 U301_59(RF OUT) V_RF2=3.0V or Fc=Local_freq + 175.05 Replace U301 U301_59(RF OUT) Need to check measure Level U301_66 or Send command PA_CNT Replace U304 Level is adjustable? U301_59(RF OUT) Replace F306 Fc=Local_freq + 175.05 SAMSUNG Proprietary-Contents may change without notice 1-10...
  • Page 13 VBATT(U302_14,15,16)=3.2~4V around 30dB or Replace U302 Need to check F304_1 around same power F304 & neighbor parts with U302 output Need to check F303 insertion loss F304 & neighbor parts under 3dB DONE SAMSUNG Proprietary-Contents may change without notice 1-11...
  • Page 14 3. STH-N375 Exploded View and its Parts List 1. Cellular phone Exploded View SAMSUNG Proprietary-Contents may change without notice...

  • Page 15: Cellular Phone Parts List

    STH-N375 Exploded view and its Part List 2. Cellular phone Parts List SEC CODE Location Description Remark Silver GH75-01724A FRONT COVER SPEAKER 3001-001210 GH75-01826A KEY PAD MAIN PBA GH82-00107A GH07-00143A MIC HOLDER GH73-01024A GH59-00376A SHIELD COVER GH75-01895A VIBRATOR GH31-00019A COVER CONNECT...

  • Page 16: Serial Cable

    STH-N375 Exploded view and its Part List 3. Test Jig (GH80-00614A) Serial Cable Power Supply Cable 4. TC 5. RF Test Cable (GH44-00145G) 110V (GH39-00090A) Mexico, Colombia, Brazil 6. Test Cable (GH39-00092A) SAMSUNG Proprietary-Contents may change without notice...
  • Page 17 4. STH-N375 Block Diagrams 1. Base Band Part Block Diagram SAMSUNG Proprietary-Contents may change without notice...
  • Page 18 STH-N375 Block diagrams 2. Radio Part Block Diagram SAMSUNG Proprietary-Contents may change without notice...
  • Page 19 SPK101 Q105 R148 R143 Q107 R145 C143 C111 C145 C141 R253 R144 R251 R252 R219 C142 C180 C139 Q106 C107 C133 S217 S214 S211 S208 S218 S203 R215 R111 C109 R240 R241 C130 R121 SAMSUNG Proprietary-Contents may change without notice...
  • Page 20 C102 C103 C323 R346 L303 Q102 C318 R307 C372 C331 C325 L300 C371 C303 C336 C307 C119 R337 R313 R103 R335 C308 RV203 C157 C155 C108 C376 R304 C306 C374 C304 F301 U106 U107 R154 SAMSUNG Proprietary-Contents may change without notice...

  • Page 21: Baseband Section

    STH-N375/N371 provides the AMPS and the Digital TDMA (cellular band only) of compliance with TIA/EIA/IS-136. The radio operation of the STH-N375N371 has been implemented with the receiver, the transmitter, and the local oscillator controlled by the PLL. The circuit of the STH-N375/N371 is described as followings.
  • Page 22 STH-N375 Circuit Description & Circuit Diagrams Figure1. BEC interface and block diagram SAMSUNG Proprietary-Contents may change without notice...

  • Page 23: Lcd Module

    This part mainly interfaces with IFC (U101) and RF part. As for interface of IFC, that will be explained detail in next section. As important signals are PREAMP_G for receiver path, PAGATE, ALC_EN for transmitter path, PLL DATA, PLL CLK, PLL STRBl for PLL synthesizer, RX BAT, TX BAT for power management. SAMSUNG Proprietary-Contents may change without notice...
  • Page 24 Since the auxiliary output is not internally amplified, an external audio amplifier is applied before connection to the headset and HFK. Figure 2. IFC interface and block diagram SAMSUNG Proprietary-Contents may change without notice...

  • Page 25: Audio Codec

    HFK shares the auxiliary output with the headset for its speaker and uses the second auxiliary input for its microphone. Since the auxiliary output is not internally amplified, an external audio amplifier (U102) is applied before connection to the headset and HFK. SAMSUNG Proprietary-Contents may change without notice...
  • Page 26 2. RF Section 2-1.Introduction For playing essential role in the radio part, STH-N375 N371 includes many active components. They are U300 (LNA), U302 (Cellular band power amplifier), U301 (transceiver including up/down converter, RF and IF PLLs, Rx and Tx AGCs, IQ modulator and demodulator, limiter, and discriminator), OSC301 (RF VCO), and OSC303 (TXIF VCO).
  • Page 27 The Rx AGC has the performance of 80-dB dynamic range, 10 dB NF, and -85dBm IIP3. In the process of 1, Q demodulation, 450 kHz local signal, made by dividing 14.4 MHz reference clock, is used. SAMSUNG Proprietary-Contents may change without notice...
  • Page 28 Auto Gain Control voltage PA_CNT IFC/RFIC Power Amplifier control voltage DEMOD RFIC/IFC Discriminator output TXDA_REF RFIC/IFC Tx section common mode DC bias PON_TX BEC/Regulator TX up converter power (V_RF2:RFIC) PON_VRF3 BEC/Regulator Local Amp power(V_RF3:RFIC) SAMSUNG Proprietary-Contents may change without notice...
  • Page 29 R152 R163 R164 R131 Q108 PLL_ON VOUT3 V_RF3 ON_SW 100K R125 PON_VRF3 C138 R153 Q102 BACKLIGHT 100K R137 100K C158 C159 C157 R126 10UF 10UF 2.2UF 6.3V 6.3V 100K C160 PREAMP_G 10UF 6.3V N375_IFIC SAMSUNG Proprietary-Contents may change without notice...
  • Page 30 SCAN(2) ZD205 ZD211 10NF S208 S209 SCAN(5) ZD203 SCAN(3) KEYLED_EN ZD208 S210 S211 DP_RX_DATA SCLK SIN_2 NOTE: WAITING FOR REPLAY FROM SAMSUNG ABOUT C_F PIN SCAN(7) SCAN(4) S212 S213 S214 DP_TX_DATA SOUT_2 SCAN(5) S215 S216 S217 HP_PWR ZD207 ZD206 BATT...
  • Page 31 V_RF2 C421 TX_IN TX_I R367 R368 TX_QN 2.2K TX_Q RFOUT C426 C422 C424 C423 C425 56PF 4.7NF 10NF 100NF R369 R370 2.2K C427 R371 R372 8.2NF 470K R373 100K C428 R374 6.2K N375_RF SAMSUNG Proprietary-Contents may change without notice 6-11...