bc250-console/WIRING.md

BC-250 Console — Power Wiring Guide

Wiring a Mean Well LRS-350-12 (12 V / 29 A / 350 W) to the BC-250's J1000 PCIe 8-pin power input, with an AC-side power switch.

⚠️ The AC side of this build is mains voltage. It can kill you. Work with the cord unplugged, never trust a switch to isolate, keep AC terminals covered when done (the LRS-350 ships with a terminal cover — use it), and if you are not comfortable with mains wiring, have someone qualified do §2.

1. Parts

Item	Notes
Mean Well LRS-350-12	Screw-terminal PSU: L, N, FG (AC side) + 3× +V, 3× −V (DC side)
PCIe 8-pin pigtail, 16 AWG	The female receptacle end mates with J1000. Must be PCIe, not EPS/CPU — the keying differs and EPS swaps 12 V/GND. Never force a connector.
Fused + switched IEC C14 inlet module	The cleanest "power switch": cord socket, rocker, and fuse in one panel part. Rated ≥ 250 VAC / 6 A. Fit a 5 A slow-blow fuse (PSU pulls ~4 A max at 115 V, half that at 230 V).
Grounded (3-wire) IEC mains cord	Earth is not optional — the PSU chassis and FG must be earthed.
Ring or fork crimp terminals + ferrules	For the PSU screw terminals. Bare stranded wire under screws loosens over time.
Heat shrink, zip ties	Insulate every AC joint; strain-relieve everything.
Multimeter	Non-negotiable for §4.

2. AC side (mains → PSU)

 IEC inlet module                          LRS-350-12
┌───────────────────┐
│ L ──── FUSE ──── SWITCH ────────────────► L
│ N ──────────────────────────────────────► N
│ E (earth) ───────────────────────────┬──► FG (ground symbol)
└───────────────────┘                  └──► case earth stud (if separate)

• Fuse and switch go in the Live line only (a double-pole switch that also breaks N is even better; never switch only N).
• Insulate the inlet's spade terminals with heat shrink or boots — they're live whenever the cord is plugged in, switch position irrelevant.
• Earth goes straight through, unswitched and unfused, to FG.
• Fit the PSU's plastic terminal cover after wiring.

3. DC side (PSU → J1000)

J1000 pinout (from the BC-250 hardware docs):

[ GND GND GND GND ]      3 × 12 V pins, 5 × GND pins
[ GND 12V 12V 12V ]

• Run each of the three 12 V wires to its own +V terminal and the ground wires to the −V terminals (bundle grounds 2-per-terminal if the pigtail has five). The LRS-350 has three terminal pairs precisely so you can split high current — at the board's ~220 W TDP that's ~18 A total, ~6 A per 16 AWG wire. Comfortable.
• Keep the run short — under ~1 m limits voltage drop.
• Ferrules or ring terminals on every wire; screw them down hard and tug-test.
• Don't extend or thin the wires: 16 AWG minimum, as delivered.
• No inline DC fuse needed — the LRS-350 has over-current, over-voltage, and short-circuit protection built in.

4. Verification — BEFORE the board ever sees power

With the pigtail connected to the PSU but NOT to the board:

1. Continuity (AC off, cord unplugged): beep out each connector pin to its PSU terminal. Confirm the three pins on J1000's 12V positions trace to +V and all others to −V. Match the pinout above against the actual connector — identify which row is which by following the wires, not by assuming latch orientation.
2. Voltage (AC on, board disconnected): switch on. Measure across the connector's 12 V/GND pins: expect 12.0–12.2 V (trim with the PSU's +V ADJ pot if needed). Then probe every pin pair — any 12 V on a pin that maps to GND means STOP and re-check.
3. Switch off, plug into J1000 (it only seats one way — if it doesn't seat, it's the wrong connector, do not force), then proceed to §5.

5. The power switch (how the console turns on and off)

The BC-250 has no case power button — it was a rack blade. Instead:

AUTO_PWRON1 jumper → pins 1-2 (factory default; also matches the BIOS AUTO_PWRON setting from the install checklist). The board now boots automatically the moment 12 V appears — so the rocker on the IEC inlet is the console's power switch, exactly like a TV:

Action	Result
Rocker ON	PSU powers up → board auto-boots → GNOME login
Shut down from GNOME / sudo systemctl poweroff	Board off; PSU still energized (standby). Stays off until AC is cycled.
Rocker OFF → ON	Full power cycle → boots fresh
Rocker OFF	Everything dead. Fine to do after a soft shutdown; the OS is btrfs and the image is atomic, but teach the kid "menu shutdown first" anyway.

Notes:

• Jumper position 2-3 instead makes the board wait for a power-button press — useless in a custom case (there's no accessible button; don't use this mode).
• J2001's PGD pin powers the board off when shorted to ground — that's a blade-chassis signal, not a power button. Leave J2000/J2001 unconnected.
• Leave the console rocker-ON overnight sometimes: automatic OS/app updates install while it's powered.

6. Fans (they also need 12 V)

• CPU_FAN1 is a standard 4-pin PWM header: [ PWM Tach 12V GND ] — BIOS fan curve applies. Put the primary heatsink fan here.
• More fans: a PWM splitter on CPU_FAN1 (fine for 2–3 standard fans), or run extras directly off a spare +V/−V pair (they'll run full speed, always — crude but effective for case airflow).
• Don't forget airflow over the backplate — the GDDR6 underneath runs hot and has no temperature sensor.

7. First power-on

1. J1000 seated, fans connected, DisplayPort to TV, keyboard for BIOS.
2. Rocker ON. Expect: fans spin, DisplayPort shows POST within ~30 s.
3. No signs of life in 30 s → rocker OFF, re-do §4. Do not keep retrying.
4. First stop: BIOS — confirm the firmware/VRAM settings from the install checklist, then boot the installer USB.