利用外接电源修理按键式电话机,不占用电话线,对他人正常通话影响很小,是一种简单可行的方法。1.不同型号的按键式电话机,在接入市电话线路上和用稳压电源检修时,各种工况的电流和电压是不相同的。笔者测试了几种型号电话机的数据,见附表。从表中所测的数据来看,在用稳压电源检修时,宜取9V电压较稳妥,若取12V电压易损坏开关管。2.挂机时的电流应近似为零,否则即使摘机,电流正常,拨号能听到脉冲号音,当接入市话线上仍无法发 The use of external power repair button-type telephone, do not take up the phone line, the normal conversation of others is small, is a simple and feasible method. 1. Different types of push-button telephone, access to telephone lines in the city and the use of regulated power supply maintenance, the current and voltage of various conditions are not the same. I tested several models of telephone data, see Schedule. Measured from the table data, the use of regulated power supply overhaul, it is appropriate to take the 9V voltage is more secure, if 12V voltage is easy to damage the switch. 2. On-hook current should be approximately zero, or even off-hook, the current is normal, the dial can hear the pulse number, when access to the local line is still unable to send