Kenwood NXR-700H Service Manual

NXR-700H107Overview of Start-up Operation:When the Modem control MPU (IC325) reset line logicswitches as high, the MPU reads the boot program from theinternal ROM of MPU and then initializes the peripheral de-vices. After this boot-up process completes, the MPU startsworking with the programs (application programs) stored inflash memory (IC314) to process the preprogrammed tasks.During the process, the MPU transfers the program to theRX DSP IC (IC323) and TX Vocoder DSP IC (IC324). It alsoconfirms the operating status of these DSP ICs. After a se-ries of processes completes, the Modem control MPU con-firms the operational status and then transmits and receivesthe operation transfer command set to/from Main MPU(IC703) using 115200 bps UART communications.• Possible Symptoms if the Block (mainly BGA IC)MalfunctionsRef. No. Element ofBlock Presumption SymptomsIC703 Main MPU• Since the boot program cannot be executedat all, the LEDs do not light or flash.• The operations that should be executed byIC703 are not processed.• Runaway of IC703.IC17FlashMemoryon RF con-trol MPUblock• Migrated to the programming mode (Write).(“PG” appears on the 17-segment LEDdisplay.)• The operations that should be executed byIC34 are not processed.• Runaway of IC34.IC314FlashMemoryon Modemcontrolblock• Migrated to the programming mode (Write).(“PG” appears on the 17-segment LEDdisplay.)• The operations that should be executed byIC325 are not processed.• Runaway of IC325.IC323 RX DSP• While the boot program is executed, theoperation stops (the status LED is flashing).• The operations that should be executed byIC323 are not processed.• Runaway of IC323.IC324TXVocoderDSP• While the boot program is executed, theoperation stops (the status LED is flashing).• The operations that should be executed byIC324 are not processed.• Runaway of IC324.TROUBLE SHOOTING / 故障排除启动操作概述 :当调制解调器控制 M P U ( I C325) 复位线路逻辑转换为高时，该 M P U 将从 M P U 的内部 R O M 读取引导程序，然后初始化外围设备。完成该引导过程后，MPU 将以闪存 (IC314) 内储存的程序 ( 应用程序 ) 开始工作，对编程的任务进行处理。处理过程中，MPU 将程序传送到 RX DSP IC(IC323) 和 TX声码器 DSP IC(IC324)。此外，它还确认这些 DSP IC 的运行状态。一系列过程完成后，调制解调器控制 M P U 将确认运行状态，然后利用 115200 bps UART 通信发送 / 接收发到 / 来自主 MPU(IC703) 的操作传送指令集。• 区块 ( 主要是 BGA IC) 发生故障时可能存在的现象有关号码区块元件可能出现的故障IC703 主 MPU• 由于引导程序根本无法执行，LED 不点亮或闪烁。• 应由 IC703 执行的操作无法得到处理。• IC703 失控。IC17RF 控制MPU 块上的闪存• 转移到编程模式 ( 写入 )。(17 段 LED 显示上出现“PG”。)• 应由 IC34 执行的操作无法得到处理。• IC34 失控。IC314调制解调器控制块上的闪存• 转移到编程模式 ( 写入 )。(17 段 LED 显示上出现“PG”。)• 应由 IC325 执行的操作无法得到处理。• IC325 失控。IC323 RX DSP• 执行引导程序时，操作停止 ( 状态 LED 闪烁 )。• 应由 IC323 执行的操作无法得到处理。• IC323 失控。IC324 TX 声码器DSP• 执行引导程序时，操作停止 ( 状态 LED 闪烁 )。• 应由 IC324 执行的操作无法得到处理。• IC324 失控。