The JEU211A fire alarm is of extreme importance to the safety of people in the case of a fire in large buildings, and its repair was a real challenge for our company. Before repairing the device, we noticed that the pressing of the alarm button did not activate the alarm light, no voice could be heard (operator guiding people with voice instructions through the building in the case of fire), and it was impossible to handle the device in any way.
At the JEU211A device itself, an auxiliary chip for volume regulation was burnt out, and the Alarm diode was burnt. It had all happened because of a pierced power supply chip of 5V (78L05) which had probably, due to low quality, had a short circuit of the output voltage to the ground.
TESTING OF THE REPAIRED DEVICE
WHAT THE VIDEO SHOWS:
The video shows the testing of the device following its repair – the speaker’s voice is heard and the alarm light is on – hence it is visible that the device functions properly.