Most PS-855B units are rebranded by major industrial OEMs (e.g., TDK-Lambda, Mean Well, or Artesyn). Check these sources:
The PS-855B is a robust, electromechanical pressure switch designed to monitor system pressure and open or close an electrical circuit when a preset pressure point is reached. It is suitable for use with air, hydraulic fluids, oils, and non-corrosive gases.
The maintenance manual includes a matrix of common faults, probable causes, and remedies. Key entries include:
Symptom: System will not build pressure
Emergency Power Supply (EPS) unit manufactured by (formerly J.E.T. / BFGoodrich) and now supported by Extant Aerospace
. It provides critical backup power to aircraft instruments like attitude gyros and flight displays in the event of a total electrical failure. Southeast Aerospace Inc. 📘 Component Maintenance Manual (CMM) Overview The primary maintenance document for the PS-855B is the Component Maintenance Manual (CMM) TP-483
. This manual covers both the PS-850 and PS-855 series under ATA Chapter 24-30-08 🛠️ Key Maintenance Intervals According to L3 Service Letter SL-170 , maintenance is divided into two primary categories: Periodic Check: Required every 3 to 6 months to verify battery health and readiness. Capacitance Check: Usually performed every
to ensure the battery can hold sufficient charge under load. ⚡ Technical Specifications (PS-855B) Specification Output Voltage 24 VDC & 5 VDC (variable) 5.0 Amp/Hour Battery Type Sealed, Lead Acid (2 packs of 6 cells) Recharge Rate 50% capacity within 1 hour at 25°C Protection Short circuit, Overvoltage, and Undervoltage protection 🔋 Critical Maintenance Procedures TP 483 - PS 850 PS 855 - Rev.B | PDF | Electricity - Scribd
The PS-855B (and its predecessor, the PS-850) is an aircraft Emergency Power Supply (EPS) manufactured by L3Harris (formerly JET or Goodrich). Maintenance procedures for this unit are strictly governed by specific technical publications. Primary Manuals and Documents
To "put together" the necessary paperwork for this unit, you typically need the following documents:
Maintenance Manual (TP-483): This is the primary reference. It provides detailed instructions for repair, testing, and troubleshooting.
Battery Maintenance Guide (SL-170): A critical supplement that focuses specifically on the battery cells. It covers storage, outgassing, and periodic capacity checks.
Installation and Operation Manual (24-30-07): Essential for initial setup and verifying the unit's interface with the aircraft's electrical system. Key Maintenance Requirements
The manual specifies a rigorous schedule to ensure the unit functions during an emergency:
Periodic Checks (Every 3 to 6 Months): Required to verify the physical condition of the batteries and their basic charge status.
Annual Capacity Checks: A mandatory test to ensure the battery can still provide the required power for the specified duration.
Charging Procedures: Instructions for recharging the unit using recommended equipment like test panels and load resistors.
Storage Guidelines: If the unit is removed for storage, the battery must be maintained according to specific outgassing and temperature protocols to prevent degradation. Where to Source These Documents You can obtain official copies from these sources: ps-855b maintenance manual
L3Harris Avionics Support: The current manufacturer and source for authorized service literature and technical updates.
Scribd (TP-483 Archive): Hosts digital versions of the maintenance manual and component manuals.
Essco Aircraft: Sells printed or digital copies of the B.F. Goodrich version (TP-483).
Do you need specific wiring diagrams or a list of required test equipment for the annual capacity check? TP 483 - PS 850 PS 855 - Rev.B | PDF | Electricity - Scribd
Grand Rapids, MI 49512-9704, USA July 30, 2014. [Link] Foreword. This manual provides information intended for use by persons who, PS-850/PS-855 Component Manual | PDF - Scribd PS-850/PS-855 Component Manual | PDF. 4K views230 pages. PS-850/855 Battery Maintenance Guide | PDF - Scribd
The PS-855B (and its predecessor, the PS-850) is an Emergency Power Supply (EPS) system commonly used in aviation to provide backup power for critical flight instruments. Proper maintenance is vital for ensuring these units function during a power failure.
Below is a blog post template summarizing the key maintenance requirements found in the PS-850/PS-855 Maintenance Guide.
Keeping the Lights On: A Guide to PS-855B Emergency Power Supply Maintenance
In the cockpit, "emergency" is a word you never want to hear, but it's the one you must always be prepared for. For many aircraft, the L-3 Communications (now ACSS/L3Harris) PS-855B is the silent guardian that keeps your attitude indicators and emergency lighting alive when everything else goes dark.
However, an emergency power supply is only as good as its last maintenance check. Here is what you need to know about the PS-855B maintenance manual and keeping your unit flight-ready. 1. The Core of the System: Battery Health
The PS-855B relies on internal sealed lead-acid or nickel-cadmium batteries. Unlike your car battery, these require specific periodic attention to prevent "memory" issues or capacity loss.
Periodic Checks: According to the Maintenance Guide, batteries should undergo a physical condition and functional check every 3 to 6 months.
Outgassing & Storage: If the unit is stored for long periods, it must be recharged periodically to prevent permanent cell damage. 2. Essential Maintenance Procedures
The PS-850/PS-855 Installation and Operation Manual outlines several critical service steps:
Preflight Check: A simple cockpit test to ensure the "In-Use" or "Battery" lights trigger correctly.
Capacity Test: This is the most crucial maintenance step. It involves a timed discharge to ensure the battery can sustain the rated load for the required duration (usually 30 or 60 minutes, depending on the aircraft's certification).
Visual Inspection: Checking for cracked housings, leaking electrolyte, or corroded connector pins. 3. Qualified Service Only Most PS-855B units are rebranded by major industrial OEMs (e
It is important to note that while pilots perform the preflight, actual repairs and internal maintenance must be done by qualified personnel in accordance with FAA or local regulatory standards. The PS-855 Component Manual provides the specific electrical tolerances and assembly diagrams needed for bench testing. Why It Matters
A neglected PS-855B might show a "green" light during a quick preflight but fail five minutes into a real emergency. Regular adherence to the service literature ensures that when the master switch fails, your emergency instruments don't.
You can often find reference versions on platforms like Scribd, but always ensure you are using the latest revision approved for your specific airframe.
PS-855B Maintenance Manual
Table of Contents
1. Introduction
The PS-855B is a high-performance [insert type of equipment, e.g. power supply, amplifier, etc.]. This manual provides maintenance and repair information for the PS-855B. It is intended for trained technicians and engineers responsible for maintaining and repairing this equipment.
2. Safety Precautions
Before performing any maintenance or repair, ensure that you have read and understood the following safety precautions:
3. Maintenance Schedule
The following maintenance schedule is recommended for the PS-855B:
4. Troubleshooting
This section provides guidance on troubleshooting common issues with the PS-855B:
5. Component Replacement
This section provides instructions for replacing components:
6. Adjustments and Alignments
This section provides instructions for adjusting and aligning the PS-855B: The maintenance manual includes a matrix of common
7. Electrical Diagrams
The following electrical diagrams are provided:
8. Parts List
The following parts are used in the PS-855B:
Emergency Power Supply (EPS) unit manufactured by (formerly JET/BF Goodrich) and supported by Extant Aerospace
. The primary maintenance documentation for this device is the Component Maintenance Manual (CMM) TP-483 Primary Maintenance Documentation Component Maintenance Manual (CMM) TP-483
: This is the authoritative "by the book" source for the PS-855B. It provides detailed instructions for installation, testing, repair, and an Illustrated Parts List (IPL). Revision B (July 30, 2014)
: This is the most current version of TP-483 for both PS-850 and PS-855 models. Service Letter SL-170 (Rev. K)
: This supplemental document specifically details the battery maintenance requirements for the PS-855 series. Key Maintenance Requirements The PS-855B uses sealed lead acid batteries
that require regular servicing to ensure reliability during a total aircraft power failure. duncanaviationparts.com Periodic Check Interval : Battery condition must be checked every 3 to 6 months as outlined in L3 Service Letter SL-170 Preflight Check
: A brief functional test recommended before each flight to ensure the unit is operational. Capacitance Testing
: Performed under load to verify the battery can sustain essential flight instruments for the required duration. Storage & Recharging
: Guidelines are provided for maintaining the unit when not in active use, including procedures to prevent outgassing and ensure a full charge (rechargeable to 50% capacity within one hour at 25°C). Southeast Aerospace Inc. JET PS-855B 501-1712-02 | Duncan Aviation
The PS-855B emergency power supply, supported by Extant Aerospace, requires regular maintenance per Component Maintenance Manual (CMM) TP-483 to ensure operational reliability. Key procedures involve quarterly to semi-annual battery checks, capacitance testing, and adherence to Service Letter SL-170 for battery longevity. For the full maintenance manual, visit Scribd. PS-850/PS-855 Component Manual | PDF - Scribd
This is a helpful guide for locating and using the PS-855B Maintenance Manual.
Important Note: The "PS-855B" is not a widely recognized global model number for common consumer electronics (like a printer, TV, or laptop). It is most likely a specific industrial controller, power supply, medical device component, or an internal part number for a larger machine (e.g., from Yaskawa, Omron, Siemens, or a PCB assembly).
Because of this, a generic manual does not exist. Follow this guide to find the correct manual for your specific device.
For a standard switched-mode power supply (SMPS), these steps are universal:
The manual is your foundation, but modern tools make repair faster.