Small daughterboard typed I/O Board (HP precedent: 821169-001/821190-001 power button boards are I/O Board; smart card boards I/O Board in 029-036). Power Button type held by Main (no vocab). Listed for all 8 checked SKUs. OEM parts list only; not bench-tested.
Source notes
Saved HP PartSurfer product BOM(s) on box (partsurfer/cache_<SKU>.json, captured 2026-10-28 before this loop; no new HP fetch, HP OEM cool-down ON). Listed for 8 of 8 checked US product numbers (441N4US, 2L9H4US, 435Y9US, 37A83UC, 2F5M8UC, 2Z5T0UC, 2Z6V0UC, 3V385UC; product name "HP ProBook 650 G7 Notebook PC (166J4AV)"). HP description: "SPS-POWER BUTTON BD W/CABLE 15". Keyword: PC Board. OrderFlag: 1. (via MM-LOOP-039).