黑金刚ＴＣ—７８０Ｌ大功率无绳电话机应急维修章捷ＴＣ—７８０Ｌ型无绳电话是仿大哥大外型系列产品之一，在市郊使用较多。由于市郊线路状况较差，振铃电压有时偏高，使电话机振铃电路易产生故障。故障现象手机在守候位置，外线有振铃手机无反应。。分析检修检查主机和... Black King Kong TC-780L high-power cordless phone emergency repair Zhang Jie TC-780L-type cordless phone is a big brother looks like one of the series, in the suburbs to use more. Due to the poor condition of the suburban lines, the ringing voltage is sometimes high, making the telephone ringing circuit prone to failure. Symptoms mobile phone waiting position, there is no response outside the ring phone. . Analysis and maintenance check host and ...