FOTEK E81M: not registering presses on the cut/coag pedal
Что было
The electrosurgical unit stopped recognising presses on the cut and coag pedal. The case mentioned a possible E05 code.
Что проверили
- The pedal, its cable and connectors were checked - no mechanical or visible damage.
- The reed-switch pedal was checked (the reed switches are potted with silicone inside) - the switches themselves worked.
- The signal from the pedal was traced to the board and checked with an oscilloscope, probing around the logic chip to localize the fault to the board.
Причина
The engineers found that the 74AC14 logic chip on the board had failed - the signal from the pedal did not pass beyond it. In this case the pedal and cable were healthy, so the problem was in the unit itself.
Что сделали
The 74AC14 chip was replaced - after that the unit began to register presses on both the cut and coag pedals. The case is closed as solved.
Безопасность
Before opening the unit, unplug it from the mains and let the internal capacitors discharge, and after repairing the board, conduct a full electrical safety test (protective grounding, patient leakage currents) before returning the device to operation.
Вывод: If pressing the pedal does nothing at all, it is not necessarily the pedal - trace the signal all the way to the board before ordering or replacing the pedal.
Разбирается в курсе: Метод поиска неисправностей медицинской техники →
Заметка написана по обезличенному случаю из практики сервисных инженеров. Это не инструкция производителя и не даёт допуска к работам. Независимая заметка; названия — товарные знаки их владельцев.