The indicator light inside the T1000's 'Call Button' is flashing continuously

[zmhqh]

大家好：
我是来自中国的华。我有一台西门子T1000，虽为中国生产，但其所有电路板与德国原产T1000完全一致，仅打字轮和键盘上的跳线存在差异。我想更换一个国际通用打字轮，但在中国很难找到。于是我向Henning先生求助，没想到他竟从德国免费寄来了两个全新的打字轮。他的热心帮助让我深受感动，在此再次向他表示感谢！
现在我的T1000又出现了新问题（在此以前是正常的）：最左侧的“呼叫键”内的指示灯持续闪烁，且机器无任何反应。我已检查过机箱开关和输纸开关，均未发现问题。目前尚不清楚故障原因，特向各位朋友请教。
多谢！
华+++

Hello everyone:
I am Hua from China. I own a Siemens T1000, which is manufactured in China but has all its circuit boards identical to the German-made T1000, with only differences in the typewriter wheel and jumpers on the keyboard. I wanted to replace it with an internationally compatible typewriter wheel, but finding one in China proved extremely difficult. So I turned to Mr. Henning for help, and to my surprise, he sent two brand-new typewriter wheels free of charge from Germany. His warm assistance deeply touched me, and I would like to express my sincere gratitude once again!
Now, my T1000 has a new issue（Before this, everything was normal）: the indicator light inside the leftmost 'Call Key' is flashing continuously, and the machine is unresponsive. I have checked both the case switch and the paper feed switch, but found no issues there. The cause of the malfunction remains unclear at this time, so I am writing to seek advice from all of you friends.
Thank you very much!
Hua+++

[380170JFK]

Hi,

The flashing light indicates a faulty line current (less than 5 mA) or polarity inversion.