我院XJJ-4型心脏急救装置使用不到两年烧坏三支热笔，上只笔电流输出管。热笔记录部分老出问题，不是记录不上，就是开机后笔热太快，烧焦记录纸。笔者对照机器实际电路及元件，作了如下改进。1．热笔电流输出管3BGS是塑封的，改为带金属片的中功率管，装在机壳上，确保不一会 Our hospital XJJ-4 cardiac emergency device burn out three hot pen less than two years, only the pen current output tube. Hot pen record part of the old problems, not record is not, that is, pen boot hot too fast, scorched record paper. The author controls the actual circuit and components of the machine, made the following improvements. 1. Hot pen current output tube 3BGS is plastic, replaced with metal sheet in the power tube, mounted on the chassis, to ensure that a short while