BAOJIE BJ-9900 User manual

QUANZHOUBAOJIE ELECTRONICS CO.,LTD.Model:BJ-9900
Version:BJ-9900-0812-V1Page1of75
Dual BandFM Transceiver
BJ-9900
SERVICEMANUAL
----------------------CONTENTS--------------------
INTRODUCTION ..2
PERSONAL SECURITY ..... 2
CIRCUITDESCRIPTION ....3
BLOCK DIAGRAM ... .. 13
BoardUnit(Schematics, Layouts&Parts)
DisplayUnit ... .14
TX-RXUnit ...21
Panel Unit .68
Panel-Sub Unit .. ..71
VR-L/RUnit ..73
SPECIFICATION ..75

QUANZHOUBAOJIE ELECTRONICS CO.,LTD.Model:BJ-9900
Version:BJ-9900-0812-V1Page2of75
INTRODUCTION
Scope ofthismanual
Thismanualprovidesnecessarytechnicalinformationforthemaintenanceand
inspection ofmobileradioBJ-9900.Maintaining this device needs professional
knowledgeoftheoperationofsurface chips assembleNon-professionaloperationwill
leadto permanentlydamagesother thanqualityassurance, and evenin somecountriesit
maybeillegal.
Thismanualisgenerallycorrectand complete,but Baojiewill notbearsany
responsibilityforthedamagescausedbytypographicalorothererrors.Ifanytechnical
informationdiscrepanciesarefound , pleasenotethatwewillbeverygrateful.
Baojiereserveexplanationrights.Meanwhile,Baojiecompanywillremain therightof
changing productdesignsandspecifications
PersonalSecurity
uForpersonalsafety, pleasenotethefollowing tips:
uDonottransimit before alltheRF plugs are carefullyconfirmedoranyopenplug
havenot beconnecttothematchingport.
uTurnoffthepower anddonot operatethisequipment whennear thetheelectric
squib ornear flammablegas.
uToavoid electromagneticinterferenceorproblemscausedbythebattery
compatibility,pleaseturnofftheradiowhere there are marks "NO RADIO",suchas
hospitals andotherhealthcareplace

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Version:BJ-9900-0812-V1Page3of75
CIRCUITDESCRIPTION
Receiversignal channel
Mainband 430MHZ Signal
430MHzsignaltransmits to Antennathroughahighpassfilternetwork,andalowpass
filter networkswitching diodeD1029,D1030{}and}D1001,thentransmit to Mainband
RF amplifier Q1001through another lowpass filter network.
Amplified430MHzsignaltransmits toTunedvibrationvariableresistancefilter
networkthrough theswitchD1002,whichincludeD1004.D1005,D1006andrelated
circuit.andthenittransmitstothefirstmixer Q1003.MeanwhileUHFlocaloscillator
signalwhichcomesfromUHF-VCO/BQ1116 transmit to thefirstmixer Q1003 and
generatefirstIF of38.55MHzmain band.
Mainband 144MHz signal
144MHzsignaltransmits to Antennathroughahighpassfilternetwork,andalowpass
filter networkswitching diodeD1113,D1114,D1115,D1116andD1117thentransmit to
Mainband RF amplifier Q1014through anotherlowpassfiliter network.Amplified
144MHzsignaltransmits to first mxierQ1016throughTunedvibrationvariable
resistance filter networkthincludingD1017.D1005,D1006andrelatedcircuit.
MeanwhileVHFlocaloscillatorsignalwhichcomesfromVHF-VCO/BQ1120transmit
to thefirst mixer Q1016 andgeneratefirst IF of38.55MHzmain band.
Main band IFandaudiosignal

QUANZHOUBAOJIE ELECTRONICS CO.,LTD.Model:BJ-9900
Version:BJ-9900-0812-V1Page4of75
38.55MHzmain band firstIF signalissent to thecrystalfilter FL1001 andFL1002. The
crystalfilter toremovethoseunwantedmixer products,andthensent to theIF amplifier
Q1027 IF ICIC1044.
Meanwhilethe13MHzCrystalpartX1002 exportthetriplefrequencyviaQ1042 to
generate39MHzsecond localoscillatorsignalandtransimit to IF IC1044 where
39MHzsecondLO and 38.55MHzMain bandfirstLO mixedtobe450KHzMain band
secondIF.
450KHzmain bandsecond IF throughthefilterswitchD1039/D1041transmit to
CeramicFilter whichremovetheother signalexcepttheuseful andthentransmit to
ceramicdiscriminatorCD1001viatheIF amplifier inIC1044.Theceramic
discriminatorwillremoveanyVarianceinAmplitudein450KHzIF signalbefore voice
detecting .
DemodulatedMainbandaudiorestore thenetworkbandnetworkingandaudio switch
throughsignal, and thenhandlebyaudioprocessorIC1042.And thefilteredaudio signal
transmit toaudio switchIC1066andIC1067.
Whenthebuilt-in speaker isselected,theaudiosignalwill beamplifiedbyIC1069and
thenbeprovidedto thebuilt-inspeaker.Whentheexternalspeaker isselected,theaudio
signalwill beamplifiedbyIC1068 andthentransmit throughtheexternalspeaker jack
to theexternalspeaker.
sub-band 430MHzsignal
430MHzsignaltransmits to Antennathroughahighpassfilternetwork,andalowpass
filter networkswitchingdiodeD1029,D1030{}and}D1001,thentransmit to sub-band

QUANZHOUBAOJIE ELECTRONICS CO.,LTD.Model:BJ-9900
Version:BJ-9900-0812-V1Page5of75
RF amplifier Q1002through another lowpass filiter network.
Amplified430MHzsignaltransmits toTunedvibrationvariableresistancefilter
networkthroughtheswitchD1009,whichincludeD1011.D1012,D1013 andrelated
circuit.andthenittransmitstothefirstmixer Q1005.MeanwhileUHFlocaloscillator
signalwhichcomesfromUHF-VCO/AQ1123transmit tothefirstmixer Q1003 and
generatefirstIF of49.95MHzSub-band
Sub-band 144MHzSignal
144MHzsignaltransmits to Antennathroughahighpassfilternetwork,andalowpass
filter networkswitching diodeD1113,D1114,D1115,D1116andD1117thentransmit to
MainbandRF amplifier Q1015through another lowpass filternetwork.Amplified
144MHzsignaltransmits to first mixerQ1017throughTunedvibrationvariable
resistance filter networkincludingD1020.D1021 ,D1022 andrelatedcircuit.
MeanwhileVHFlocaloscillatorsignalwhichcomesfromVHF-VCO/AQ 1126transmit
to thefirst mixer Q1017 andgeneratefirst IF of49.95MHzsub-band .
Sub-band IFand audiosignal
49.95MHzsub-bandfirstIFsignalissenttothecrystalfilter FL1003and FL1004.The
crystalfilter removethoseunwantedmixerproducts,andthenthroughtheIFamplifier
Q1035 sent to IF ICIC1047.
Meanwhilethe16.8MHzCrystalpartX1003exportthetriplefrequencyviaQ1043
to generate50.4MHzsecondlocaloscillatorsignalandtransmits toIF IC1047where
50.4MHzsecondLO and 49.95MHzsub-bandfirst signalmixedtobe450KHz
sub-band secondIF.
{450KHzsub-band secondIF transmit toCeramicFilterCF1003whichremovethe

QUANZHOUBAOJIE ELECTRONICS CO.,LTD.Model:BJ-9900
Version:BJ-9900-0812-V1Page6of75
other signalexcepttheusefulandthentransmit toceramicdiscriminatorCD1001via
theIF amplifier in IC1047.TheceramicdiscriminatorwillremoveanyVariancein
Amplitudein450KHzIF signalbefore voice detecting .Theceramicdiscriminatorwill
removeanyVariance inAmplitudein450KHzIF signalbefore voicedetecting.
Demodulatedsub-band audio restorethenetworkandaudioswitchD1048through
signal,and thenhandlebyaudioprocessorIC IC1043.And thefilteredaudiosignal
transmit toaudio switchIC1066andIC1067.
Whenthebuilt-inspeaker isselected,theaudiosignalwill beamplifiedbyIC1069
andthenbeprovidedto thebuilt-inspeaker.Whentheexternalspeaker is selected,the
audiosignalwillbeamplifiedbyIC1068 and thentransmit throughtheexternalspeaker
jacktotheexternalspeaker.
Squelch control
Mainband
whenthereisnotreceivablecarriersignalinmain band,theoutputnosiesforthe
IC1044detectorwill beamplifiedwhilethebandpasswillbefilteredbytheIC1044''s
noisesamplifiedpart.Thegenerateddirectvoltagewillbetransferredto ofMain CPU
IC1104 pin31whichwill compare thesquelchstandardlevelwiththesettablesquelch
levelin thefrontpanelwhichcansettedthroughSQLkey.
whenthere isno receivablecarrier signalinmain band ,Thepin76inIC110willkeep
in LOWposition to forbiddentheaudiooutput ofthespeaker.

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Sub-band
whenthereis not receivablecarrier signalin sub-band, theoutput nosiesfortheIC1047
detectorwill beamplifiedwhiletheband passwill befilteredbytheIC1047''snoises
amplifiedpart.Thegenerateddirectvoltagewill betransferredtoofMain CPUIC1107
pin28 whichwillcompare thesquelchstandardlevelwiththesettablesquelchlevelin
thefront panelwhichcansettedthrough SQLkey.
Transmittersignalchannel
Audio signal
Theaudiosignalwhicharriveatloud-speakeraretransferredtotheaudioamplifier
U3001 ofPANEL-SUBUNITthrough theMicPlug J3004.Theamplifiedaudiosignal
viathefrontpanelseparatedplugJ3002and J1005 transmit to TX-RXunit where the
audiosignalistransferredto theaudioprocessorIC IC1042 andrelatedcircuit.
430 MHz signal
TheaudiosignalwhicharrivesatlIC1042are transferredtovariableresistance diode
throughtransistorexchanger Q1114andQ1115.Where thefrequencymodulates
composedandemissionvoltagecontrolledoscillatorwhichcomposeofUHF-VCO/B
Q1116and D1081.
Adjustedtransmittingsignalthroughabuffer amplifier Q1117,Q1118, Q1119 anddiode
switchD1099, D1101 senttothepreamplifier Q1132.

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AmplifiedtransmittingsignalreachingQ1132transmit todiodeswitchD1107through
thediodeswitchD1106 anddriveamplifier, and finallybeamplifiedbypower amplifier
Q1135to generatemore than35Woutputpower .Thesethreestepsare controlledby
autopower controlcircuit.
35WRF signalthrough ahighpass filter networktransmit to theantennaswitchD1118,
D1119andD1120,and thenthroughalow passfilternetwork,andanother high-pass
filter networktransmits to theantennajack.
144MHz signal
TheaudiosignalwhicharrivesatIC1042are transferredtovariablecapacitancediode
D1082 andD1085throughtransistorexchanger Q1114andQ1115.
AmplifiedtransmittingsignalreachingQ1132transmit todiodeswitchD1108through
thediodeswitchD1105,D1106anddriveamplifier,andfinallybeamplifiedbypower
amplifier Q1135togeneratemore than50Woutputpower .
Q1132cometo beamplifiedtransmission signalviaadiodeswitchD1105, D1106,and
sentto thediodedriveamplifier switchQ1134D1108, Q1135ultimatelyamplifiedby
thepower amplifier,resultinginmore than50Wofoutputpower.Thesethreestepsare
controlledbyautomaticpower controlcircuit.
50WRF signalthrough ahighpass filter networktransmit to theantennaswitchD1113,
D1114and thenthroughalowpass filter network,andanother high-passfilter network
transmits to theantennajack.
Automatic powercontrolcircuit

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430 MHzsignal
Partoftheoutputofthepower amplifier correctedbytheD1121 and D1122,Thensent
to theAPCAutomaticPower ControlIC1129.AsaDCvoltage,APC AutomaticPower
Control ofthepower amplifier outputlevelis proportionalto.
InIC1129 on,cometo thepower amplifier andtheDCvoltagecorrectionover to the
main CPUIC1104 tothereferencevoltageto produceacontrolvoltage.hecontrol
voltageregulatedpower supplyvoltageto thepreamplifierQ1132,Q1134 driver
amplifier andpower amplifierQ1135,inthecaseofchangingtheantennaloadto
maintainastableoutputpower.
144 MHzsignal
Partoftheoutput ofthepower amplifier correctedbytheD1109 and D1110, andthen
senttotheAPC AutomaticPower Control Q1129.AsaDCvoltage,APC Automatic
Power Control ofthepower amplifierisproportionalto theoutput level.
OntheQ1129tocorrectover tothepower amplifier totheDCvoltagetothemain
CPUIC1104with thereference voltagetoproduce acontrol voltage.Thecontrol
voltageregulatedpower supplyvoltageto thepre-amplifierQ1132,Q1134driver
amplifier andpower amplifierQ1135,inthecaseofchangingtheantennaloadto
maintainastableoutputvoltage.
PTTElectric circuit
430 MHzsignal
Whenyou pressthePTTswitch,thesubCPUU2001'spin23tothe"low"position,

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Version:BJ-9900-0812-V1Page10of75
thenlaunch"PTT"command to themain CPUIC1104.
Whenthe"PTT"command is received,themain CPUIC1104 pin45tothe"high"
position, thenactivatestheUHFtransmitter switchQ1096.
WhentheQ1096'sUHFtransmitter switchis activated, it controls theantennaswitching
diodeD1118,D1119,D1120,modulationswitching diodeQ1114,Q1115,diodeswitch
D1099,D1101,D1106,D1107,andAPCautomaticpowerswitchQ1130,Q1131.These
activatedthe430MHztransmittercircuit.
144 MHzSignal
Whenyou pressthePTTswitch,thesubCPUU2001'spin 23tothe"low"position,
thenwill launchthe"PTT"command tothemain CPUIC1104.
Whenthe"PTT"command is received,themain CPUIC1104pin 46tothe"high"
position, thenactivatesaVHFtransmitter switchQ1096.
WhenQ1096 forVHFtransmitter switchisactivated,itcontrolstheantennaswitching
diodeD1118,D1119,D1120,modulationswitching diodeQ1114,Q1115,diodeswitch
D1099,D1101,D1106,D1107,andAPCautomaticpowerswitchQ1130,Q1131.These
activatedthe144MHztransmittercircuit.
PLLElectric circuit
Main band
Cometo UHF-VCO/BQ1116 partoftheoutputbufferamplifier Q1117andthrough
diodeswitchD1086,senttothePLLIC1109 programmabledivider. Here it isaccording
to themain CPUIC1104relatedto thefrequencydivisiondatais dividedand sent tothe