Regular upkeep is mandated by FAA standards and L3 Service Letters to ensure battery reliability. Periodic Check (Every 3–6 Months)
Provides 5 VDC output for critical standby electronics.
Once you have the manual, understanding its structure saves hours. A typical PS-855B maintenance manual contains seven key sections.
Locate and evaluate these critical hardware blocks inside the chassis: Linear Regulation Stage ps-855b maintenance manual
: A mandated full-load test to verify the batteries can maintain the required voltage over a specific duration. Discharge Testing , the output voltage must remain above after a 48-minute discharge period. Recharging Protocol : Units must be recharged within
This points to a failing reference voltage. The manual instructs you to probe the zener diode (ZD1) for stable voltage (e.g., 6.2V). If noisy, replace. Also check C11 (the main filter cap) for high ESR.
Inspect hydraulic filters and replace them if necessary. Regular upkeep is mandated by FAA standards and
The unit automatically maintains a full charge during normal flight operations but can be recharged to 50% capacity within one hour if depleted. Necessary Maintenance Tools
Turn off the unit, disconnect all cables, and place it on an ESD-safe mat.
: For any repair or maintenance task, follow the detailed procedures outlined in the manual. This usually includes step-by-step instructions and sometimes diagrams or pictures. A typical PS-855B maintenance manual contains seven key
The , designed by L-3 Communications Avionics Systems (formerly B.F. Goodrich), is a critical component in aircraft safety, providing reliable backup power to flight instruments. Ensuring its operational readiness requires adherence to a strict maintenance schedule, outlined in technical manuals such as the TP-483.
For aviation maintenance professionals, the PS-855B maintenance manual is more than a collection of pages—it is a commitment to safety, reliability, and regulatory compliance. Always ensure you are working with the most current, official documentation from L3Harris or your specific aircraft's AMM to keep this critical system ready to protect the skies.