Simplex 566-071H Circuit Board Card Assemblies

Simplex 566-071H is an OEM System Power Supply (SPS) PC board for Simplex fire alarm systems. As a circuit board card assembly, it serves as the panel’s primary power-supply module within the 4100-series family, delivering the regulated DC power required by the control electronics and enabling battery charging through the panel’s power subsystem. This 566-071H component is the official cross-reference to 742-342, allowing substitution in panels that reference that designation. Manufactured by SimplexGrinnell (a Tyco/Johnson Controls brand), the board is used in legacy Simplex 4100U and 4100ES control panels and related configurations, and is commonly sold as an OEM replacement by fire-safety parts vendors. The SPS PC board integrates with the panel harness and associated connectors used on older Simplex power configurations, making correct model-year and chassis compatibility important during replacement. Replacements of this part are typically pursued when servicing aging systems to restore reliable power delivery to the control circuitry and signaling circuits, without altering the panel’s core architecture.