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富丽VIP-1000型放像机相当普及,早期成立的录像放映队大多是使用这种机子,由于连续工作,使该机经常出现故障,本文介绍用万用表判断CPU的好坏。该机CPU集成电路型号为μUPD7538D,是(42)脚双列封装,日本NEC产品。 1.查电源电压,测(21)脚应有4.9伏的电压。如无,一般为R_(544)开路。 2.查复位脉冲,用万用表测①脚电压,当电源开关接通的瞬间要有0.5V的脉冲,然后降为零。 3.查时钟振荡,该集成电路②、③脚与外接晶体X_(501)、电容C_(503)、C_(504)构成400kHz时钟振荡,先测③脚电
Fuli VIP-1000 player quite popular, the early establishment of the video projection team mostly use this machine, due to continuous work, so that the machine often fails, this article describes the use of multimeter to determine the CPU is good or bad. Machine CPU integrated circuit model μUPD7538D, is (42) dual-pin package, Japan NEC products. 1. Check the power supply voltage, measuring (21) feet should have 4.9 volts. If not, R_ (544) is generally open. 2. Check reset pulse, with a multimeter test ① pin voltage, when the power switch connected to the moment to have 0.5V pulse, and then dropped to zero. 3. Check the clock oscillation, the integrated circuit ②, ③ feet and external crystal X_ (501), capacitor C_ (503), C_ (504) constitute a 400kHz clock oscillation,