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ATX Power Board

The ATX Power Board break out the connections from an ATX power supply to provide a switch-mode steady 3.3V, 5V and 12V current.

ATX Power Board

Note that you can mount the board in a case. The distance between the screws is 85 mm, the board itself is 95 mm. The backside provides a nicer view of the board when you hide the solder connections. Depending on which side you want to use, you have to solder:

  • Frontside: R1, R3, R5, R7, R9, R11, and D1, D3, D5, D7, D9, D11
  • Backside: R2, R4, R6, R8, R10, R12, and D2, D4, D6, D8, D10, D12

The board has banana connectors for 3.3V, 5V, and the two 12V rails. The spacing between the power connector and its corresponding ground connector is standardized.

Put a rectangular rocker switch (e.g. R1966A) in the cutout, and connect its pins (common and ON) to the pins at SW1.

ATX Main (J1)

The main ATX power connector has pinout:

  1. +3.3VDC — +3.3VDC power.
  2. +3.3VDC — +3.3VDC power.
  3. GND — Ground.
  4. +5VDC — +5VDC power.
  5. GND — Ground.
  6. +5VDC — +5VDC power.
  7. GND — Ground.
  8. PWR_OK — High (+5V) when the PSU has started.
  9. +5VSB — +5V stand-by power.
  10. +12V1DC — +12VDC power from rail 1.
  11. +12V1DC — +12VDC power from rail 1.
  12. +3.3VDC — +3.3VDC power. (not connected)
  13. +3.3VDC — +3.3VDC power.
  14. -12VDC — -12VDC power. (not connected)
  15. GND — Ground.
  16. PS_ON — Pull to ground to start PSU.
  17. GND — Ground.
  18. GND — Ground.
  19. GND — Ground.
  20. -5VDC — -5VDC power. (not connected)
  21. +5VDC — +5VDC power.
  22. +5VDC — +5VDC power.
  23. +5VDC — +5VDC power.
  24. GND — Ground.

ATX P4 (J2)

The ATX P4-connector provides extra power, and has pinout:

  1. GND — Ground.
  2. GND — Ground.
  3. +12V2DC — +12VDC power from rail 2.
  4. +12V2DC — +12VDC power from rail 2.

Molex Connectors (J3-J5)

The board provides three Molex 8981 connectors on rail +12V1DC, with pinout:

  1. +12V1DC — +12VDC power from rail 1.
  2. GND — Ground.
  3. GND — Ground.
  4. +5VDC — +5VDC power.

Molex Connectors (J6-J8)

The board provides three Molex 8981 connectors on rail +12V2DC, with pinout:

  1. +12V2DC — +12VDC power from rail 2.
  2. GND — Ground.
  3. GND — Ground.
  4. +5VDC — +5VDC power.