Motorola B3 MTX Series Istruzioni per gli Interventi

HT 1000™, MT 2000™,MTS 2000™, andMTX SeriesHandie-Talkie® Portable Radios Theory/TroubleshootingManual

I. INTRODUCTIONThis publication covers a large family of portableradios: HT 1000, MT 2000, MTS 2000, and MTX seriesunits. They are software driven, an

35VRegulatorU709U705Micro C ASF ICU701U706Audio PA5VSB+Controller BoardBattery7.5V+B+PA Module5VRegulatorVCOB ICALCT5L105CR108RXL122L121 VccU105U202T5

In the transceiver, SWB+ is routed directly to the 5vregulator (U202). The regulated 5v supplies the IF IC(U3), the reference oscillator (U203), the F

The filtered RF signal is then applied to the RF inputof a broadband mixer IC. An injection signal (FIRSTLO), supplied by the FGU, is applied to the s

The RF PA module is a multi-stage amplifier, whichhas the required gain to produce an output level of sev-eral watts. Some harmonic filtering is accom

D. Receiver Back End (See Figure 6)In the IF IC, the first IF frequency is down convert-ed, amplified, filtered, and demodulated to produce therecover

overall PA gain as appropriate. Another function of thedetector is to provide a signal when the VSWR exceedsthe threshold level. This signal, combined

B. Digital ArchitectureThe Motorola microprocessor, in conjunction withthe SLIC, performs the functions of controlling the inter-nal workings of the r

I. INTRODUCTIONIn this section of the of the manual, a more detaileddescription of the radio and some special circuit is given.For a better understand

The OPT B+ voltage powers external accessoriesused with the radio.C. B+ Routing and DC Voltage Distribution (for an Open Architecture Controller and a

The open architecture controller board uses Flashmemory (U715) in place of conventional EPROMs.This allows the firmware to be reprogrammedthrough the

C80, C86, C87, C88, C97, C99, L3, L4, L5, and L30(VHF); or C4 thru C7, C88 thru C94, C99, and L11 thruL15 (UHF) to improve the spurious rejection.Via

3. ALC CircuitsCoupler module U104 samples the forward powerand the reverse power of the PA output voltage.Reverse power is present when there is othe

the SRL. The loop divider adds or subtracts phase tothe prescaler divider by changing the divide ratio via themodulus control line. The output of the

The final stage in the receiver front end is a 2-polecrystal filter, FL12. The crystal filter provides some ofthe receiver’s adjacent channel selectiv

2. Microcomputer Clock SynthesizerUpon power-up, and assuming that the ASF ICreceives a proper 2.1MHz input at U701 pin 33(which comes from the transc

dual NPN transistor IC, U704. When either of theoutputs (U705 pin 66, PC1 or U705 pin 65, PC0) isat a logic high, the corresponding output of U704(pin

a. Sub-audible Data (PL/DPL)Sub-audible data is composed of low-frequencyPL and DPL waveforms for conventional opera-tion. Although it is referred to

U705 pin 51, PE1. After passing through the 8-bit digital attenuator, the audio goes to a bufferamplifier and exits the module at U701 pin 21(RX AUD O

HT 1000TM, MT 2000TM, MTS 2000TM, and MTX SeriesHandie-Talkie®Portable RadiosTheory/Troubleshooting ManualMotorola8000 West Sunrise BoulevardFort Laud

the external memory devices, U705 has 1k of RAM and512 bytes of EEPROM on chip. Miscellaneous logic andswitching functions are provided by U703, U709,

common symptom is the RESET line goes low peri-odically, with the period being on the order of msec.5. RAMThe on-chip 1k static RAM from U705 provides

(J701 pin 9) to go low. The multiprocessor detectsthis transition using U710, and then sends a com-mand to the display in order to read the keypaddata

Although it is referred to as “sub-audible data,”the actual frequency spectrum of these wave-forms may be as high as 250Hz, which isaudible to the hum

secure board it is decrypted and convertedback to analog format, and then fed back to theASF IC from the AUX RX line (J702 pin 9). It isthen routed to

Pin 10, the Vpp/CTS pin, also serves several func-tions. When reprogramming the Flash memory device,this pin carries the programming voltage, Vpp. The

I. INTRODUCTIONServicing the HT 1000, MT 2000, MTS 2000, andMTX series portable radios requires the localization ofthe malfunctioning circuit before t

D. Check Overall Receiver Operation1. 20dB Quieting Sensitivity TestA good overall check of receiver operation is the20dB quieting sensitivity measure

Foreword The information contained in this manual relates to all HT 1000™, MT 2000™, MTS 2000™, and MTX Series Handie-Talkie® portable radios, unless

32* Note: Assumes Power Beep is EnabledNOStartNOMAEPF-23279-OGood PowerUp Beep?*Is ThereTX Power?Is TXDeviationOK?NOPressMonitorAudioNoise?ReceiveAu

33TROUBLESHOOTING FLOW CHART(800/900MHz Transceiver/Open Architecture Controller)* Note: Assumes Power Beep is EnabledYESStartNOMAEPF-23440-OGood Po

34TROUBLESHOOTING FLOW CHART #1A(VHF/UHF Transmitter RF)No/Low PowerTX Current> 500 mA?RF at RFJack, S101Pin 3?Replace U105NOYESRF at Cathode ofCR1

35TROUBLESHOOTING FLOW CHART #1B(800/900MHz Transmitter RF)MAEPF-23441-OREQUIRES:OJEDI Troubleshooting ChartISS.CORRECTEDASMARKEDILLUSTRATOR DATEENGIN

36TROUBLESHOOTING FLOW CHART #2A(VHF/UHF Receiver RF)Bad SINADBad 20Db QuietingNo Recovered AudioAudio atC306?CheckControllerSpray or Inject 1st IF in

37TROUBLESHOOTING FLOW CHART #2B(800/900MHz Receiver RF)No-High SINADYESCheck Comp.Q1, CR5, C54, C55, L24, C56 & C57Inject73.350MHz at Pin 1 FL1-1

38TROUBLESHOOTING FLOW CHART #3A(VHF/UHF DC Switch)No R5Q105 Pin 2Voltageat Q105Pin 3?Voltageat U103,Pin 3?Voltageat Q107,Pin 2?Voltageat Q107,Pin 3?V

39TROUBLESHOOTING FLOW CHART #3B(800/900MHz DC Switch)REQTroubleILLUSTRATOR DATEDESCRIPTIONLETEDITOR DATESW3/12/93JWB3/22/93No R5/No T5Voltageat Q108,

40TROUBLESHOOTING FLOW CHART #4A(VHF/UHF Frequency Generation Unit - FGU)FGU No Lo Injection/TXUnlockCheck Continuitybetween J1-17 &J104-17, J1-15

41TROUBLESHOOTING FLOW CHART #4B(800/900MHz Frequency Generation Unit - FGU)FGU No Lo Injection/TXUnlockANOYESVDC atV Con Pin 1U205<0.7V?ReplaceU20

LIST OF TABLES...

42TROUBLESHOOTING FLOW CHART #5A(VHF/UHF Voltage Controlled Oscillator - VCO)VCO TX/RX UNLOCKCheckVDC atC246(VCTRL)VDC13V/0.7V/Drifting?4.6V atCollect

43TROUBLESHOOTING FLOW CHART #5B(800/900MHz Voltage Controlled Oscillator - VCO)JEDI Troubleshooting ChartISS.REVISIOCORRECTEDASMARKEDILLUSTRATOR DATE

44TROUBLESHOOTING FLOW CHART #6A(VHF/UHF, Closed Architecture, No Receive Audio)NoAudioAudio atR755?Audio atC306?NoAudio atExt. Spk.NoAudio atInt. Spk

45TROUBLESHOOTING FLOW CHART #6B(800/900MHz, Open Architecture, No Receive Audio)No/Low AudioCheck Audio J301 Pins 10 & 12Check U3and U3 Circuitry

TROUBLESHOOTING FLOW CHART #7A(VHF/UHF, Closed Architecture, No Transmit Deviation)JEDI No TX DeviationTroubleshooting ChartISS.CORRECASMARKEDILLUSTRA

47TROUBLESHOOTING FLOW CHART #7B(800/900MHz, Open Architecture, No Transmit Deviation)REQUIREJETroubleshoILLUSTRATOR EDATELETTERIEDITOR DATESW3/12/93N

48TROUBLESHOOTING FLOW CHART #8A(Closed Architecture Controller)Closed ControllerCheckPower UpAlert ToneOK?Note 1.Radio Buttonfunctions andSignallingP

iiCONTENTS (cont.)TITLE PAGETHEORY OF OPERATION (DETAILED FUNCTIONAL DESCRIPTION)I. INTRODUCTION ...

6881200C15-A*6881200C15*MOTOROLA and the Stylized M Logo are registered inthe U.S. Patent and Trademark Office. All other product orservice names are

iiiTABLE TITLE PAGELIST OF TABLES1 Option Select Definition...

ALC- Automatic Level Control; a circuit in the transmit RF path that controls RF power amplifier output, provides leveling overfrequency and voltage,

I. PURPOSEThis manual will provide a theoretical explanation ofthe HT 1000, MT 2000, MTS 2000, and MTX Seriesportable radio’s operation, troubleshooti