ATX Power Supply Rear Switch: What It Actually Does

Why can’t my ATX power supply start when I toggle the rear switch?

Many users mistakenly regard the rear switch of the ATX power supply as the power-on button. In fact, its function and the correct startup method are as follows:
Rear Switch Function: It only controls the connection/disconnection of AC mains power.
When set to ON: The power supply is connected to the mains and enters a low-power standby state, waiting for the startup signal from the motherboard.
When set to OFF: The power supply is completely disconnected from the mains, and no power is supplied to any component.
Correct Startup Steps:
Step 1: Flip the rear switch to ON and plug in the power cord.
Step 2: Press the power button on the computer case.
Step 3: The motherboard sends a startup signal to the power supply, which then starts to output power to all hardware (motherboard, CPU, etc.).
Warning: Frequent toggling of the rear switch may cause power surges and damage the power supply or motherboard.

ATX Power Supply DOA (Dead on Arrival) Troubleshooting Guide

What should I do if my ATX power supply is dead on arrival and not working at all?

If your ATX power supply is non-functional upon receipt, please follow these troubleshooting steps before contacting customer service:
Check the Rear Switch First
Confirm the rear AC switch is set to the ON position. The power supply cannot enter standby mode if the switch is OFF.
Verify Power Connection
Plug the power cord into a different wall outlet (avoid power strips with overload protection to rule out socket issues).
Ensure the 24-pin motherboard power connector and 4/8-pin CPU power connector are fully inserted and locked.
Check for Short Circuits
Make sure there are no loose screws or metal debris inside the case that could cause a short circuit (a short circuit may trigger the power supply’s protection mechanism and prevent it from starting).
Provide Detailed Fault Information
If the power supply still does not work, please record:
A video showing the rear switch position, power cord connection, and the result of pressing the case power button.
Photos of the power supply’s appearance and connector pins (to check for shipping damage).

Warning

Warning Instructions for Voltage Selector Switch
WARNING: This equipment is equipped with a 110V/220V voltage selector switch. The operation of voltage switching is directly related to the safety of the equipment and the personal safety of users. It is imperative to strictly follow the requirements of this instruction for operation; any unauthorized operation is strictly prohibited!
When the equipment is connected to a 220V power supply, if the voltage selector switch is mistakenly toggled to the 110V position, the internal circuit of the equipment will bear a current far exceeding the rated value due to voltage mismatch. This will instantly cause a circuit overload, resulting in a sharp heating of components, which in turn will lead to the equipment smoking and, in severe cases, a direct explosion. This may cause major safety accidents such as fire and electric shock to the surrounding environment and personnel.
To ensure the safe and stable operation of the equipment and avoid safety risks, please be sure to confirm that the input voltage of the power supply is consistent with the position of the voltage selector switch before connecting to the power supply: when connecting to a 220V power supply, the switch must be set to the 220V position; when connecting to a 110V power supply, the switch must be set to the 110V position. Please carefully check before operation and only turn on the power after confirmation.
Any equipment damage, safety accidents and related losses caused by violating this warning instruction and incorrect operation of the voltage selector switch shall be borne entirely by the person who performed the unauthorized operation.

Power Supply Explanation (20+4pin)

Warning Instructions for Voltage Selector Switch

WARNING: This equipment is equipped with a 110V/220V voltage selector switch. The operation of voltage switching is directly related to the safety of the equipment and the personal safety of users. It is imperative to strictly follow the requirements of this instruction for operation; any unauthorized operation is strictly prohibited!

When the equipment is connected to a 220V power supply, if the voltage selector switch is mistakenly toggled to the 110V position, the internal circuit of the equipment will bear a current far exceeding the rated value due to voltage mismatch. This will instantly cause a circuit overload, resulting in a sharp heating of components, which in turn will lead to the equipment smoking and, in severe cases, a direct explosion. This may cause major safety accidents such as fire and electric shock to the surrounding environment and personnel.

To ensure the safe and stable operation of the equipment and avoid safety risks, please be sure to confirm that the input voltage of the power supply is consistent with the position of the voltage selector switch before connecting to the power supply: when connecting to a 220V power supply, the switch must be set to the 220V position; when connecting to a 110V power supply, the switch must be set to the 110V position. Please carefully check before operation and only turn on the power after confirmation.

Any equipment damage, safety accidents and related losses caused by violating this warning instruction and incorrect operation of the voltage selector switch shall be borne entirely by the person who performed the unauthorized operation.

specification

1: Power supply size: 150mm * 160mm * 86mm

2: Power standard: ATX 12V

3: Applicable to CPU range: AMD, Intel

4: PFC type: active PFC

6: Maximum power: 1000W

7: Efficiency: 89%

8: Input voltage:90V-264V

9:+ 3.3V output current 20A

+ 5V output current 20A

+ 12V1 output current 66A

– 12V output current 0.5A

+ 5Vsb output current 3A

10: Support wide voltage: Yes

11: Support temperature control PWM: Yes

12: Certification: CB, CCC, FCC, Class, B, CE, ROHS

13: Product weight: 2500g

14: Support power: 20P / 24P motherboard