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例一机型:东芝2500XH 故障现象:不能存储节目信号检修方法:根据故障现象,判断可能是节目存储器M6M80011P损坏,或是没有同步脉冲及AFT信号作用到微处理器M50436—683SP所致。 QA01(M50436—683SP)的(36)脚为同步脉冲输入脚(如图1),在调谐选台期间CPU若检测到该脚有同步信号输入,就判为接收到电视信号,然后根据(35)脚AFT电压来实现自动搜索调谐的准确性。然后CPU在(30)脚时钟脉冲的作用下,由(34)脚输出波段数码及调谐数码给QA03(M6M80011P),以便在相应预置号存储
Example a model: Toshiba 2500XH Symptom: can not store program signals Maintenance methods: According to the fault phenomenon, determine the program memory M6M80011P damage, or no synchronization pulse and AFT signal to the microprocessor M50436-683SP caused. (36) of QA01 (M50436-683SP) is the sync pulse input pin (Figure 1). During the tuning and tuning, if the CPU detects the sync signal input on this pin, it will judge that the TV signal is received, ) Pin AFT voltage to achieve automatic search tuning accuracy. Then CPU (30) under the clock pulse, the output from the (34) foot band digital and tuned digital to QA03 (M6M80011P), so that the corresponding preset number stored