The manual specifies a 28-terminal removable connector block:
When working with the MS-7826, follow these standard procedures for installation: ms 7826 ver 1.0 manual
: HP occasionally releases BIOS updates for the MS-7826. Note that some updates are designed to be flashed under specific operating systems (like Windows 8.1) and may not execute properly under Windows 10 or 11. ms 7826 ver 1.0 manual
power connector and a 4-pin ATX 12V connector. While standard, always verify pinouts if upgrading to a non-HP power supply to avoid damaging the board. ms 7826 ver 1.0 manual