Kenwood NX-720 Service Manual

Also see for NEXEDGE NX-720: Installation guide Instruction manual Technical details Service manual Instruction manual

Contents

NX-720(G)/72030● Checking power supply voltageChecking voltagePoints to be checked Normal voltage33M IC401 (5 pin) 3.3V15M IC408 (5 pin) 1.5V33A IC406 (5 pin) 3.3VPower supply of each device is connected through the coil.[ASIC]33M: L508, 15M: L510, 33A: R571[DSP]33M: L503, 15M: R505[FLASH]33M: L501[SRAM]33M: L504● Checking the clockChecking the clockPoints to be checked Normal voltage (3.3V)18.432MHz IC506 (4 pin) 18.432MHzWhen a normalvalue is confirmed.When a normalvalue is confirmed.● Checking the Reset/Control signalChecking the control signal input to the ASICPoints to be checked Normal voltageRST (RESET) IC504 (1 pin) 3.3V/BINT IC402 (1 pin) 3.3V/OVRB D403 (Cathode side) 3.3VChecking the ASIC input switch signalThe POWER key is pressed and held.Points to be checked Confirmed voltagePOWER R690 ON: 0VThe ignition key is kept ON. OFF: 3.3VPoints to be checked Confirmed voltage/IGN C633 (Q504-Collector Side) ON: 0VOFF: 3.3VRemove the R556 . If it oscillates normally, the DSPand ASIC may be broken.Remove the R501. If it oscillates normally, the DSPand ASIC may be broken.The BGA parts are not broken.Checking for an abnormal point33M has an abnormal voltage.[ASIC]Remove L508 to check the voltage of the 33M.If the voltage becomes normal, the ASIC is broken.[DSP]Remove L503 to check the voltage of the 33M.If the voltage becomes normal, the DSP is broken.[FLASH]Remove L501 to check the voltage of the 33M.If the voltage becomes normal, the FLASH is broken.[SRAM]Remove L504 to check the voltage of the 33M.If the voltage becomes normal, the SRAM is broken.15M has an abnormal voltage.[ASIC]Remove L510 to check the voltage of the 15M.If the voltage becomes normal, the ASIC is broken.[DSP]Remove R505 to check the voltage of the 15M.If the voltage becomes normal, the DSP is broken.33A has an abnormal voltage.[ASIC]Remove R571 to check the voltage of the 33A.If the voltage becomes normal, the ASIC is broken.If the voltage is not corrected, there is a problemother than the BGA parts.When an abnormalvalue is confirmed.When an abnormalvalue is confirmed.When an abnormalvalue is confirmed.● Checking the output signalfrom the ASICPoints to be checked Normal voltage/FRST R516 3.3VIf the /FRST is always 0V, the ASIC is broken.If the /FRST repeats 3.3V and 0V at intervals,the ASIC, FLASH and SRAM may be broken.When an abnormalvalue is confirmed.When an abnormalvalue is confirmed.When a normalvalue is confirmed.When a normalvalue is confirmed.When a normalvalue is confirmed.Check the other point then BGA parts.Fault Diagnosis of the BGA (Ball Grid Array) IC■ OverviewA flowchart for determining whether or not the transceiver can be powered on (the LCD does not function even if the powerswitch is turned on) due to broken BGA parts.■ BGA partsASIC (IC507), DSP (IC502), FLASH (IC501), SRAM (IC503)When the BGA IC is problematic, please bring the printed circuit board (X57-8230-12 /-13) in for service. Various ESN/defaultadjustment values are written on the printed circuit board for service.Additionally various ESN stickers are included.After the printed circuit board has been readjusted, please attach any ESN stickers to the chassis. When “ESN Validation” isused with Trunking, you must modify the ESN register.TROUBLE SHOOTING