HYT Science and Technology Co TM-800U1 Mobile Radio User Manual

Shenzhen HYT Science &Technology; Co Ltd Mobile Radio

Contents

Users Manual I

TM-800 UHF SERVICE MANUAL 123 Troubleshooting Flow Charts Normal Power-on alert tone?MCU CheckRF circuit can’t be drivenYesSpeaker works well?NoReplace the speakerNo`9.8304MHz works normally?YesRead available or not?YesQ117 works normally?Replace Q117Check 5VMCU works wellPin10 is of high level?Check the control circuitCheck read circuitResetNoYesYesYesNoNoYes
TM-800 UHF SERVICE MANUAL 124 Normal power supply?VCO CheckReplace Q116NoRx oscillates ? And CV voltage is normal?YesQ706 works normal?No`Check Q703 outputs normally? Check Q703Normal feedback? Check Q124Check power supply circuit.Check CPU data circuit.16.8MHz oscillates?Q705 works normal?Replace Q706Replace Q705YesYesYesYesYesYesNoNoNoNoNo
TM-800 UHF SERVICE MANUAL 125 Power supply of AF IC126 is normal?No receiveOutput of IC126 is normal?Output of electronics volume IC125 is normal?Check IC126Output of IC104 is normal?The 2nd local oscillator works normally?L135 works normally?Is there any input in IC119 PIN16 IF?Is there any RF signal?Replace L135Check X105Check IC125Check work status of IC119 &peripheral componentsCheck VCOFPC & Speaker work normally?NoNoNoCheck Q601 passYesOutput of IC106 is normal? Check IC104Output of IC121 is normal? Check IC106YesYesYesYesYesYesYesYesYesNoNoNoNoNoNoNoCheck power supply circuit.
TM-800 UHF SERVICE MANUAL 126 No outputPower supply works normally?Check power supply circuitCheck Q131 & Q110Check driver stage.Check transistor Bias voltage and low pass network Repair transmission network.Check the suited network.VCO maintenanceFlow chartReplace Q128Replace Q127CompletedCompletedCompletedControl voltage is normal?Current is normal?Driver stage is normal?Normal Power?Normal power?Normal power?NoYesLowHigh NoYesYesYesYesNoYesNoNo
TM-800 UHF SERVICE MANUAL 127 Exploded View 8941403938373635343332313029 28 27 26 25 24 23 22 2120191817161514131211107654321

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