Power, cooling, startup.
The BC-250 does not connect to a PSU like a standard desktop motherboard. A separate PCIe lead feeds the board, fans need power and control, and an ATX supply needs a startup connection.
Choose an enclosed PSU that fits your case and has its own compatible PCIe 6+2 cable. For a first build, follow a documented enclosure and parts combination. Open-frame industrial supplies introduce mains-terminal wiring and need a different guide.
The linked Apevia ITX-PFC500W has a 160 × 73.66 × 41.2 mm enclosure and no rear power switch. A generic instruction to “flip the PSU switch” will not start that model. The owner confirms its ATX plug is the standard 24-pin type shown below. The smaller 10-pin plug in the separate example belongs to an FSP NUC supply.
Which on/off switch works with an ATX PSU?
A standard ATX supply needs its PS_ON# signal held low to stay on. For straightforward manual control, the owner uses the linked SQXBK 24-pin starter switch. It plugs into the motherboard end of the supply’s own ATX cable; the BC-250 is still powered separately by the PCIe 6+2 lead.
Manual switch or board-aware controller?
| Control | What happens | Before buying |
|---|---|---|
| Maintained ATX starter switch | You enable the PSU, then shut Linux down before switching the supply off. | Choose an insulated assembly for the standard 24-pin ATX plug. Verify board auto-start separately. |
| Momentary PC case button | Directly across PS_ON# and ground, it holds the supply on only while pressed. | It needs suitable control electronics for toggle behavior; the button alone is not an ATX starter. |
| BC-250 power controller | Uses additional board signals for coordinated power control, according to its design. | Follow the exact controller’s installation instructions, board connections and firmware requirements. |
Finished build: secure and insulate the assembly, keep the switch accessible, and use Linux’s shutdown command before cutting power. An LED on the switch does not confirm that Linux has finished shutting down.
See the standard 24-pin connection and owner photograph →
Prefer a BC-250-specific controller?
The maker of the mosfet.party ATX 24-pin ps_on adapter describes a pre-wired BC-250 controller with a panel button. Check current availability and the maker’s installation video. This is an ordinary reference link; we have not tested this controller.
Intel: PS_ON# behavior. SQXBK listing and owner confirmation checked September 12, 2026.
The connection walkthrough.
Follow the three routes below. With JavaScript enabled, the controls highlight one at a time. Start with the board and fan photos, then use the ATX startup diagram below.
Three jobs. Three connections.
Board power. Seat the complete 8-pin plug and latch. CPU/EPS 4+4 is a different cable.
Standard four-pin fan header. A powered hub also takes its own PSU power. J4003 supplies signals, not fan power.
Use the standard 24-pin route for the Apevia and normal ATX supplies. The FSP NUC example has a different plug. AUTO_PWRON1 separately controls the board’s startup.
Owner photographs and documentation checked September 2026. The complete assembled wiring route has not yet been photographed and reproduced from this guide.
Find the connectors on your board.
| Label | Purpose | Check |
|---|---|---|
| J1000 | Main PCIe 8-pin 12 V board input. | PCIe/GPU 6+2 lead. Do not substitute EPS/CPU 4+4. |
| CPU_FAN1 | Standard four-pin PWM fan header. | No maximum current has been verified here. A splitter does not add power capacity. |
| J4003 | Fan control/tach signals. | It does not provide fan power. Do not treat it as CPU_FAN1. |
| AUTO_PWRON1 | Board auto-start selection. | Documented pins 1–2: start on applied power. Pins 2–3: wait for board power button. Identify pin 1 from the silkscreen triangle, not a left/right guess. |
The ARCTIC SATA-powered hub is one documented option. For a powered fan hub, follow its own manual: the PSU powers the fans, and the motherboard connection provides control and a speed reading. Verify the hub, fans and wiring as a set.
Original connector documentation and board photos Example powered-hub connection manual
03 / START THE POWER SUPPLY
The small connection that turns it on.
An ATX PSU normally gets its on/off signal from a desktop motherboard. The BC-250’s PCIe power input does not provide that signal. A jumper or suitable switch connects the PSU’s PS_ON# signal to ground to enable its main outputs.
Standard 24-pin ATX cable · including the Apevia
Face the terminal openings toward you, with the latch at the top. In the top row, connect the fourth opening from the left (pin 16, PS_ON#) to the fifth (pin 17, ground). This view is the cable’s motherboard end, not its wire-entry side or a socket on the PSU.
Jumper or switch?
A jumper stays connected. The PSU’s main outputs stay enabled while AC power is present. A PSU without a rear switch needs an accessible way to disconnect AC power.
A maintained on/off switch can make and break that same signal-to-ground connection. An ordinary momentary case button, wired directly across those terminals, only holds the PSU on while pressed; it needs a suitable controller to behave as a toggle.
Shut Linux down before switching off the supply. With a fixed jumper, the PSU and its powered fans can remain on after the operating system shuts down. PSU startup and the board’s AUTO_PWRON1 setting are separate.
Corsair: 24-pin terminal orientation and pins 16–17 Intel: how PS_ON# controls the supply
MODEL-SPECIFIC / OWNER’S HARDWARE
FSP500-30AS: the smaller NUC plug.
The owner also uses an FSP500-30AS 500 W supply sold for Intel Ghost Canyon NUC systems. This photographed version has a 10-position startup plug. The Apevia above uses a standard 24-pin plug; these layouts are different.
Use a secured, insulated startup connection in a finished build. The BC-250 still takes the supply’s PCIe/GPU 6+2 lead; the FSP’s separate EPS/CPU lead is for a different purpose. Check the available fan and accessory power connections before substituting a NUC supply for a standard ATX model.
Photographs and exact model identified by the owner, September 7, 2026. Intel NUC 9 specifications, §2.18: FSP500-30AS and cable types. The NUC specification establishes the PSU family; the illustrated jumper positions come from the owner’s photos.
Connect in a deliberate order.
Disconnect mains and identify the parts.
Check the PSU model, its supplied cables, case requirements and the board labels. Stop if the pieces do not match the documented build.
Connect the PCIe 6+2 lead to J1000.
Use the correct PSU output and its own cable. Join the 6+2 sections properly, then seat the whole connector so the latch engages. Avoid tension on the board socket.
Connect cooling.
Use CPU_FAN1 for a compatible fan route or a properly powered hub. Verify the total load against the actual power source rating; do not assume an unverified header limit.
Connect the ATX startup control.
For a standard ATX supply, use a compatible insulated starter or maintained switch assembly at the motherboard end of its own 24-pin cable. Follow the 24-pin diagram, or the separate FSP NUC reference for that exact version. Secure and insulate the connection so it cannot touch another terminal or the chassis.
Check board auto-start.
With power still disconnected, identify AUTO_PWRON1 and its current setting. Use the documented auto-start setting or the board’s correctly identified power button arrangement.
Inspect before applying power.
Secure the board, clear loose screws and check airflow. Apply power using the verified control arrangement; observe the fans immediately.
Your first-power checklist.
If fans fail to start, something smells hot, or a connector becomes hot, disconnect power and inspect the setup before another attempt. A picture on the monitor does not prove the cooling is adequate.
Continue to first boot ↗