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1.“全无”故障检修 用三用表置R×10k挡,测量静态时电话机挂机和摘机两种状态的输入回路电阻。测得电话机挂机和摘机两种状态的输入回路电阻值均为无穷大,说明输入回路有开路故障,应重点检查引线,压簧和引线连接端子;若测得挂机和摘机两种状态输入回路电阻小于几kΩ,说明电话机输入回路已有短路故障,故障原因是引线短路和输入回路压敏电阻击穿。 2.对方听不到讲话、自己吹风无侧音(其它功能均正常)故障的检修 目前,电话的送受话电路有采用集成电路的;也有采用分立元件的。现以采用集成电路的为例介绍故障检修。
1. “No” troubleshooting with the use of the table set R × 10k block, measuring the static state of the phone hook and pick two state input loop resistance. Measured the phone hang up and pick up the two states of the input circuit resistance are infinite, indicating that the input circuit has an open circuit fault, should focus on inspection leads, compression spring and lead connection terminal; if the measured hook and pick two state input Circuit resistance is less than a few kΩ, indicating that the phone input circuit has a short circuit fault, the cause of the fault is the lead short circuit and the input circuit varistor breakdown. 2. The other party can not hear the speech, their own hair without side tone (other functions are normal) Troubleshooting At present, the phone to send and receive circuits have adopted integrated circuits; also used discrete components. Now taking the integrated circuit as an example to introduce troubleshooting.