Programme’s After Market Services NHD–4 Series Transceivers Disassembly & Troubleshooting Original 11/97
NHD–4 Disassembly & Troubleshooting PAMS Technical Documentation CONTENTS Disassembly Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baseband Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Troubleshooting Diagram; Flash Programming OK, part 1 . . . . . . . . . .
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting RF Node Power Checks – AMPS Mode . . . . . . . . . . . . . . . . . . . . . . . . . . CDMA Receiver Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CDMA RX Quick Test with Service Software . . . . . . . . . . . . . . . . . . . . . . Set Up CDMA RX Test . . . . . . . . . . . . . . . . . . . .
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NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Disassembly Instructions Remove the battery. Now remove two back cover screws and remove the back cover by lifting it away. 2 1 4 Then remove six chassis screws.
NHD–4 Disassembly & Troubleshooting PAMS Technical Documentation Remove the chassis by lifting. Turn around the chassis and open the display module a little. Open the display module connector by pressing both sides of connector and slide off the display module cable.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Turn chassis again and remove four chassis screws. 1 3 4 2 Remove the plastic shield and throw it away (it is disposable). Now you can separate the system module from the bottom shield by lifting it away.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation Baseband Troubleshooting Overview Baseband oriented failures are usually found out during Flash updating of the phone, the phone should be started to minimum mode and current consumption measured. If current consumption is within acceptable limits and MBUS registration is OK, flash is programmed. If flash programming fails, service software can be used to activate MCU self tests.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Phone takes all available current If phone takes all available current, the problem can be caused by bad solder joints in PSL_+3V(N500), components around it and bottom connector(X701).
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Flash Programming, part 1 FLASH programming OK MBUS registration OK? YES Does LCD display turns ON? YES NO NO Check D706 pins 3,80 ASIC pins 130,86 3 Power stays on? YES Does LCD display turns ON? NO NO Check X701 Short circuits in data data lines. data line disconnected, VREF disconnected YES VBATT N500 pin 5,20 ? YES C507 OK? NO MBUS line X701 pin 5, Is 4.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Flash Programming, part 2 2 NO D706 pin 10 XSYS_RESET +3V after power on? YES 15.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Flash Programming, part 3 3 MBUS registration OK? YES Does LCD display turns ON ? YES D703 initialization (Factory Values Set) OK? YES 4 NO NO Check D706 and D703 interface D703 pin 18,19/D0,D1 +3V to 0V during r/w operations ? YES Change D703 Page 12 Original 11/97
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Flash Programming, part 4 4 D709 /pin 23, 39 +12V while programming? NO Check X701/pin14 L700,C729,R748 R741 NO Check X701 pin 6 R736,R739,R764 C723 NO Check D706 pin 63 R725,R735,C721 YES D706 /pin 64/HOOK_RXD2 pulses during prog? YES X701 pin 7 /PHFS_TXD2 pulses during programming? YES D709 pin 10/RP +3V after power ON ? NO Check VCO_EN line at the D709 pin 10 for shorts and opens YES D709 pin 22/CE p
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; PWR Button Fault Nothing happens when PWR button is pressed Check X701 NO N500 pin 10 +3V when VBATT is connected? YES NO N500 pins 5,20 VBATT voltage? YES Change N500 NO Check UI–conn.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Audio Fault Audio fault Microphone or earphone signal missing Microphone and earphone signal missing? YES N600 pin 19/CODEC_FS from D704 N600 pin 20/CODEC_MCLK from D704 D705 pins 29,37/CODEC_FS from D704 D705 pins 27,33/CODEC_MCLK from D704 YES N600 pin 25,24/MICP,MICN N600 pin 17/PCMOUT N600 pin 21/MICENX NO Microphone signal missing? corresponding pins of UI–connector NO Earphone signal missing? Origin
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Power Up Sequence Diagram VCTCXO G300 CDCONT 13 N201 CLK 15.36MHz VRXS 4.5V 23 1 CDRFI N700 Square circuitry 63 CLK 15.36MHz VCO_EN VBAT 5.3....8V 4 5, 20 CHRGDET 21 11 PSL DETIN 12 16 N500 C507 ON 24 8 XPWROFF 9 104 VL2 168 ASIC VL3 XSYS_RESET (3.15V) MCU_INT0 (3.15V) 98 MCU_NMI (0V) 69 10 MCU 77 D706 11 66 D704 VA2 XRESET MCU_CLK (15.36MHz) 121 VA1 2 14 128 147 VL1 2 VREF ON=3.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Repairing Instructions for Flash Faulty Units 1. When the phone doesn’t start (power off after 7seconds and probably no MBUS connection) check following things: VBATT is connected to the PSL_+3V(N500) XRESET rises to 3.15V VL1 is 3.15V 32KHz clock is running. VRXS(4.5V) is connected to the VCTCXO and the crystal frequency is 15.36 MHz XSYS_RESET signal rises to 3.15V MCU_CLK signal is 15.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Power Up and MCU Self tests Malfunctions RADIO UNIT CHECK Press power on Current consumption OK? NO See Power Up Malfunction NO See Self Tests Malfunction YES Run self tests OK? YES Call process Audio check OK Page 18 Original 11/97
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Power Up Malfunction Basically there are two different problems that could occur while powering up the phone. First, the current consumption is almost zero all the time. Probably the fault is at the power circuit PSL_+3V(N500). Check all PSL_+3V(N500) connections including VBATT line. Second, the phone’s current consumption is normal for 7seconds and goes to zero after that time. The reason for this is the watchdog. 1.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation Figure 2 1.11 Check VCO_EN is high (3.15V) CDCONT(N201) pin 23. 1.12 Check VCTCXO(G300) waveform at CDCONT(N201) pin 35 looks like Figure 3. Also check that VRXS line is 4.5Vdc at CDCONT(N201) pin 13. If all these conditions are meet check solder joints for shorts and opens, if they are OK replace CDCONT(N201).
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting 1.2 Check CDRFI(N700) pin 63. See Figure 4. Is there a 15.36MHz clock signal present? – YES! Go to 1.22 / NO! GO to 1.21 Figure 4 1.21 Check this signal solder joints, if OK replace CDRFI(N600). 1.22 Check connections between ASIC(D704) and MCU (D706), especially ASIC(D704) pin 104 and MCU(D706) pin 69. If no clock is present and connection looks OK replace ASIC(D704). 2.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation 3.11 Check PSL_+3V pin 12. Voltage should be between 1.46V and 1.72V. if not check R500, R503 and VBATT voltage(5.3...8 Vdc) NOTICE! Measure pin 10 from the PSL_+3V(N500) with oscilloscope. That is watchdog signal coming from MCU(D706). There should be rising edges time to time. If all these are OK and still XPWR_RESET is low replace the PSL_+3V(N500). 3.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting 6.0 FLASH–line OK? Power up function OK! YES! Power up function OK! / NO! Do flashing again. This table might help to locate power pins on main circuits.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Troubleshooting Diagram; Power Up Malfunction Start 1.11 Check VCO_EN is 3V NO NO 1.1 VCTCXO running OK? YES 1. MCU clock running OK? YES 1.12 Check Vctcxo sine wave and VRXS is 4.5V, if OK replace CDCONT (N201) 2. MCU’s supply voltages OK? Check solder joints, if OK replace CDRFI (N700) NO 2.1 Check PSL+(N500) VL1–line at pin 4 NO 1.2 Clock signal at CDRFI (N700) pin 63 ? YES YES 3. MCU reset signal OK? 1.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Important Information This section contains information that might be helpful while troubleshooting an HD881 phone. However it is not needed to troubleshoot power up problems. 9.8304MHz clock This clock is ”ON” when the phone is set to CDMA non–slotted mode and it is ”OFF” when the phone is set to AMPS mode. It is generated inside the CDCONT(N201) from the 15.36MHz.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation Figure 7 Page 26 Original 11/97
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Transmitter Troubleshooting Introduction Troubleshooting the NHD–4 transmitter is very straight forward. Operation of the transmitter circuit changes little from AMPS to CDMA mode, only the nature of the signal transmitted is distinctly different. A substantial amount of information regarding the health of the transmitter can be determined with just a simple DMM. The detector voltage will provide you a sound estimate of the output power.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting CDMA TX Quick Checks with Service Software The Service Software contains a Quick Check for the CDMA TX. From the Test menu choose the CDMA Quick Test selection. A sub menu will appear. Select the CDMA TX Quick Check. A window will appear instructing you to feed the transmitter output into either a spectrum analyzer or CDMA test box.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting CDMA TX Gain Control – Manual Controls As the name suggests, the CDMA TX Manual Gain Control mechanism of the Service Software provides a means to manually manipulate the output power of the CDMA transmitter. This test is convenient for testing the two gain control functions of the CDMA transmitter, the CDAGCT IC and Auxiliary AGC. You can find this control within the CDMA Quick Checks selection of the Tests menu of the Service Software.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation DC Node Voltage Checks Typical nodal voltages are listed below. The phone must be at AMPS output power level 2 or maximum CDMA output power when measuring node voltages. These two states can be achieved by using the AMPS or CDMA Troubleshooting Modes.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁ
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Testing CDMA TX Gain Limiting To test the CDMA TX Gain Limiting control perform the following steps: 1. Place the phone in the CDMA Troubleshooting Mode. 2. With an oscilloscope probe the LIM_ADJ line at C807. 3. Adjust the gain of the CDMA transmitter using the CDMA TX manual gain control mechanism found in the Service Software. 4. The LIM_ADJ line will remain at about 3.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ CDMA TX Output RF Signal Level (dBm) TX_GAIN Voltage at C213 (V) TX_ICT Control Current (mA) 15 10 –5 –20 –35 1.78 1.80 1.87 1.93 2.00 0.700 0.560 0.298 0.171 0.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation AMPS Receiver Troubleshooting Introduction Troubleshooting the NHD–4 AMPS receiver isn’t unlike troubleshooting the AMPS receiver on any other Nokia phone. In fact, NHD–4 uses the same FM receiver IC as many other Nokia phones. So long as the NHD–4 phone is in an AMPS RX mode, this receiver will be on. The following tests detail ways to make the AMPS receiver operational and test its functionality.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting RSSI Check The voltage on the ungrounded end of C13 directly represents the RSSI of the phone. Checking this voltage will provide another quick indication of the health of the AMPS RX module. With the –65 dBm modulated signal mentioned above this voltage should be approximately 2.00 V. The possibility exists that the AMPS RX is working fine with a –65 dBm input, but has lost sensitivity and fails at lower input powers.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation DC Voltage Checks Check the following DC voltages with the –65 dBm modulated signal still fed into the phone and the Service Software AMPS Troubleshooting Mode initiated. •The bias voltage on the AMPS RX IC (D1), pin 4 should be approximately 4.40 V. If not, first ensure that the phone is in the AMPS Troubleshooting Mode. Check the VRXA supply voltage at C219, or CDCONT (N201), pin 42.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting •Check the RX_CAL line at R783, It should be logic level high, near 2.75 V. If not, confirm that the phone is in the AMPS Troubleshooting Mode. Ensure VRXM is at about 4.15 V at R832. Inspect V1, V708, R6, R765, R783, and R785. Ohm out the RX_CAL line from pin 114 of the ASIC N704 to R785. Chart of AMPS RX DC Node Voltages The following chart summarizes the node voltages of the AMPS RX when the phone is in the AMPS RX/TX Mode with a 881.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁ
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting CDMA Receiver Troubleshooting Introduction Troubleshooting the CDMA receiver of the phone is unique, but not complicated. The following tests detail numerous ways that the CDMA receiver functionality can be verified, all using standard test equipment. No special CDMA signal generators or measurement equipment are necessary to verify the CDMA receiver.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ DC Voltage Checks RF Input Power Voltage Drop 881.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting •Check the voltage drop across R16 at the RX_ICT line, placing one probe on either side of this resistor. The voltage drop should be approx 37 mV. If not, first ensure that the phone is in the CDMA Troubleshooting Mode. Ensure that the –75 dBm 881. 62 MHz CW signal is fed into the receiver. If fault is found then continue with the remaining receiver DC Voltage checks.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting •Check the SWAGC line at R830, should be logic level low, approx .0 V. If not, confirm that the phone is in the CDMA Troubleshooting Mode. Ensure VRXM is at about 4.40 V at R832. Inspect V708, R765 and R830. Ohm out line from R765 to the ASIC N704 pin 94. •Check the RX_CAL line at R783. It should be logic level high, near 2.75 V. If not, confirm that the phone is in the CDMA Troubleshooting Mode. Ensure VRXM is at about 4.40 V at R832.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting RF Node Powers – CDMA RX Mode A high impedance passive RF probe may be used with a spectrum analyzer to obtain the RF nodal power levels along the receiver chain. The following levels assume the above probe and a –65 dBm, 881.52 MHz, unmodulated tone input into the receiver. Maintain a 1.0 MHz span on the spectrum analyzer. A CDMA test box with spectrum analyzer capabilities will do.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation Hints and Suggestions AMPS •It is important to NOT adjust the tunable inductor L17. Doing so will NOT assist in troubleshooting a faulty receiver, it will only make things worse. This device is tuned by its manufacturer to the proper inductance. •While in AMPS Troubleshooting Mode, probe the 455 kHz ceramic filter Z4. A noise pedastle approximatly 20 kHz wide will be visible about 10 dBm above the noise floor.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Synthesizer Troubleshooting Introduction Troubleshooting the synthesizer is difficult because the oscillations that it produces cannot be measured at the output of the phone. The RF signals it generates are routed to various portions of the phone. Assuming the receiver and transmitter are functional, indirect means of determining the health of the synthesizer can be used.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation • If the signal comes up, but is very much off frequency (more than a few kHz) or is drifting around then the one or both of the PLLs is not locked. Proceed to the section titled Testing and Troubleshooting for Synthesizer Lock Error. • If no signal is seen then it is possible that the transmitter is not working.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting • Check the tune voltage on pin 1. It should be between 1.50 and 2.50 V. If not, check R302, R301, and C302. Check the RX_SLOPE and AFC PDM lines. Manually adjust them with the PDM controls within Service Software. Read the RX_SLOPE PDM voltage at R700 and read the AFC PDM voltage at R701. While tuned to channel 384 the RX_SLOPE PDM should be about 3.00 V. For channel 440 it should be 0.0 V. The AFC PDM will vary between 0.0 V and 3.
NHD–4 PAMS Disassembly & Troubleshooting Technical Documentation • Check the tune voltage at pin C. It should fall in the range of 1.5 to 3.5 V. If not, check the PLL IC. Ensure that the RF feedback is correct into the PLL at pin 6. • The RX_LO gain stage N704, pin 3 should be about 3.40 V. If not, check R803 and see that VRX is 4.40 V at C206. • The TX_LO gain stage N705, pin 3 should be about 2.70 V If not, check R809 and R815. Ensure that VTXT is approximately 4.40 V at R809 or C212.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ Hints and Suggestions Node G300 – VCTCXO, pin 1 V303 – VHF Buffer Amp – Collector V303 – VHF Buffer Amp
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting DC Supply Checks The voltage supplies used to bias the RF module is detailed below. The following table details the voltage of each supply when the phone is in either AMPS or CDMA mode. Shaded boxes indicate that a supply is active. • AMPS RX/TX mode can be achieved by initiating the AMPS Troubleshooting Mode from the Services Software. • CDMA RX/TX mode can be achieved by initiating the CDMA Troubleshooting Mode from the Services Software.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting CDAGCT IC (N100) Gain Control Test To test the gain control abilities of the CDAGCT IC (N100) perform the following steps: 5. Place the phone in the CDMA Troubleshooting Mode 6. Observe the TX output with a spectrum analyzer or CDMA test set. Be sure to read bandpower over a 1.23 MHz band. 7. Use the CDMA TX manual gain control found in the Service Software to adjust the output power from its minimum (noise floor) to 15 dBm. 8.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting For CDMA TX operation above the switchpoint, the TX_ICT current will be at its maximum, approximately 1.0 mA. There should be approximately 100 mV of voltage drop across R116. For more information on the Auxiliary AGC control feature, consult section 3.4.3.2 of this document. CDMA RX Gain Control Test To test the gain control abilities of the CDAGCR IC (N1) do the following: 3. Place the phone in the CDMA Troubleshooting Mode 4.
NHD–4 PAMS Technical Documentation Disassembly & Troubleshooting Note the PDM decimal values are not linearly related. Therefore the maximum value of 255 roles over to the minimum value of 0 at the midpoint of the scale. This explains the significant difference between the PDM decimal values of 27 dBm to 30 dBm. CDMA AGC Loop Test This procedure tests the ability of the CDMA transmitter output power to track the CDMA receiver input power.
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