Five Easy Points to Judge Whether Toxic Gas Alarms Have Malfunctions
To handle malfunctions of toxic‑gas alarms, you first need to locate fault positions and root causes. The following five methods can be used to judge whether a toxic‑gas alarm is faulty.
① Comparison Method Two units of the same model are required, one of which is in normal working condition. Operate the faulty unit and the good unit under identical conditions, then measure and compare signals at several test points. Differences between the two sets of readings indicate a fault at this location. This method requires solid professional knowledge and skills from maintenance personnel.
② Parallel‑mounting Method (Shoulder‑to‑Shoulder Method) Place a good IC chip directly on top of the chip under test, or connect good spare components (resistors, capacitors, diodes, transistors, etc.) in parallel with the suspected component with reliable contact. This approach can eliminate faults caused by internal open‑circuit or poor contact of components.
③ Tapping and Pressing Method Intermittent faults are mostly caused by poor contact or cold solder joints. "Tapping" means gently striking circuit boards or components with a rubber mallet to check whether errors or shutdowns occur. "Pressing" means powering off and firmly pressing connectors and sockets when a fault occurs, then power on again to verify if the fault disappears. If normal operation occurs after tapping the housing but fails upon repeated tapping, re‑seat all connectors first. If the problem persists, adopt other solutions.
④ Temperature‑Raising and Cooling Method Malfunctions may appear after long‑time operation or under high‑temperature summer conditions; the instrument works normally after power‑off and restarts, yet faults recur after a while. This is caused by poor high‑temperature performance of certain ICs or components. For cooling: when a fault occurs, apply anhydrous alcohol with cotton swabs onto suspected parts to cool them down and observe whether the fault disappears. For heating: artificially raise local temperature, e.g. bring a soldering iron close to suspected components (avoid excessive temperature that damages good parts) to trigger potential faults.
⑤ Replacement Method Units of the same model or sufficient spare parts are needed. Replace suspected components on the faulty device with known‑good spare parts and check whether the fault is removed.
