Sperry Marine 1885842-4

The Sperry Marine 1885842-4 (often listed as Assembly PN 03956-1885842-2 or -4) is a Solid-State Relay (SSR) Board primarily used in integrated marine navigation and communication systems.

Given the other components you’ve listed, this board is likely part of the Bridge Control or Radar System infrastructure (such as the Sperry Marine VisionMaster series) where it acts as an interface between the low-voltage control logic and high-current mechanical loads.

Technical Overview

• Part Number: 1885842-4 (Assembly 03956-1885842)

• Type: Solid-State Relay Board (Multiple channels)

• Function: It uses opto-isolation and semiconductor switching (usually TRIACs or MOSFETs) to control peripherals like antenna motors, scanners, heating elements, or external alarm indicators without the wear and tear of mechanical contacts.

• Manufacturing: These are often “Military/Industrial Grade” units, designed to withstand the high-vibration environment of a ship’s bridge or engine room.

Troubleshooting

If you are investigating a failure on this board:

• Silent Failure: Unlike mechanical relays, these do not “click.” You must use a multimeter to check if the output side is opening/closing when the input signal is applied.

• Short-Circuit Mode: SSRs often fail in the “Closed” (ON) position when they burn out. If a motor or light won’t turn off, the 1885842-4 likely has a shorted internal component.

• Revision Codes: You mentioned the -4 variant. In Sperry Marine systems, suffixes (like -2 or -4) often indicate different voltage ratings or improved thermal management. Ensure the revision matches your system’s manual.

System Integration

You have now identified five major components that likely belong to a single Integrated Bridge System (IBS) or Marine Communication Rack:

1. FC7.820.505 (CPU): The brain.

2. FC7.820.506 (DTMF): Keypad/Dialing logic.

3. FC7.820.507 (TONE): Audio/Switching logic.

4. FC7.820.504 (EXT): Telephone extension interface.