Ps-855b Maintenance Manual ((link)) Jun 2026
: Steps to identify failures in the internal charging circuit, battery packs, or 5 VDC converter.
Before performing any maintenance or diagnostic procedures on the PS-855B, you must strictly adhere to all safety protocols to prevent personal injury or equipment damage. Critical Safety Rules
Below is a structured outline of the typical content required for a maintenance manual for the PS-855B. 1. General Information & Specifications
To prevent sudden component failure, implement a scheduled maintenance routine based on operating hours. Monthly Maintenance (High-Dust Environments)
Desolder the main power transistors from the heatsink. Use a DMM in diode mode to check for shorts. Replace defective transistors. ps-855b maintenance manual
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The , manufactured by L3Harris Technologies , is a critical component in emergency power systems for aviation . As a 5.0 AMP, 5 VDC output power supply, it is often utilized to support standby instruments in aircraft, making its reliable operation paramount for flight safety.
Fan failure; blocked air vents; excessive ambient room temperature.
This is a helpful guide for locating and using the . : Steps to identify failures in the internal
The PS-855B (P/N 501-1712-02) lead-acid emergency power supply, manufactured by L3Harris/Avionics Systems, requires regular maintenance guided by CMM TP-483 and Service Letter SL-170, including visual checks for outgassing and annual capacity tests. Essential procedures involve a 5-second push-to-test for capacity, a 7.0-ohm load test for 48 minutes, and specific 8 to 23-hour recharging requirements to ensure continued airworthiness. For detailed procedures, refer to the L3Harris CMM TP-483 documentation at seaerospace.com Southeast Aerospace Inc. L3Harris PS-855B | SEAEROSPACE.COM
, search for the numbers printed on the circuit board inside the device (e.g., PCB-855B ).
| Parameter | Specification | | :--- | :--- | | | Standard 20 Gallons (75.7 Liters) | | Operating Pressure | 3000 PSI (207 Bar) Standard | | Max Flow Rate | 8.5 GPM (32.2 L/min) | | Fluid Type | ISO VG 32 / 46 / 68 Hydraulic Oil | | Filtration | 10 Micron Return Line Filter |
: The unit automatically maintains a charge from normal flight operations and can reach 50% capacity within one hour at 25°C. Use a DMM in diode mode to check for shorts
Ensure that the unit passes self-tests (if equipped) or that indicators show a charged state. 3. Battery Maintenance and Charging
Always unplug the main power cable from the electrical outlet.
Consists of active cooling fans and passive aluminum heat sinks attached to high-thermal components.
Proper maintenance of this unit is mandatory, often dictated by and stringent operational checks. This guide provides an overview of the key components of the PS-855B maintenance manual , procedures for testing, and best practices for servicing. 1. Overview of the PS-855B Power Supply
110V–220V AC (Auto-switching / Manual switch-dependent) Operating Temperature: 0°C to 40°C (32°F to 104°F) Storage Temperature: -20°C to 60°C (-4°F to 140°F) Relative Humidity: 20% to 80% (Non-condensing) 3. Preventative Maintenance Schedule