Power supply shuts down intermittently.
Cause | Solution |
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If equipped with a voltage selector, voltage selector switch on | Select the proper AC voltage using the selector switch. |
rear of computer chassis (some models) not switched to correct |
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line voltage (115V or 230V). |
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Power supply will not turn on because of internal power supply | Replace the power supply. |
fault. |
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Computer powered off automatically and the Power LED flashes Red two times, once every second, followed by a two second pause, and the computer beeps two times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause | Solution | |
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Processor thermal protection activated: | 1. | Ensure that the computer air vents are not blocked and the |
A fan may be blocked or not turning. |
| processor cooling fan is running. |
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| |
OR | 2. | Open the access panel, press the power button, and see if |
| the processor fan (or other system fan) spins. If the fan does | |
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| |
The heat sink is not properly attached to the processor. |
| not spin, make sure the fan cable is plugged onto the |
| system board header. | |
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| |
| 3. | If fan a plugged in and not spinning, replace it. |
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Power LED flashes Red four times, once every second, followed by a two second pause, and the computer beeps four times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause | Solution | |
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Power failure (power supply is overloaded). | 1. | If equipped with a voltage selector, check that the voltage |
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| selector, located on the rear of the power supply (some |
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| models), is set to the appropriate voltage. Proper voltage |
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| setting depends on your region. |
| 2. | Open the access panel and ensure the power supply cable is |
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| seated into the connector on the system board. |
| 3. | Check if a device is causing the problem by removing ALL |
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| attached devices (such as hard drives or optical drives and |
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| expansion cards). Power on the system. If the system enters |
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| POST, then power off and replace one device at a time and |
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| repeat this procedure until failure occurs. Replace the |
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| device that is causing the failure. Continue adding devices |
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| one at a time to ensure all devices are functioning properly. |
| 4. | Replace the power supply. |
| 5. | Replace the system board. |
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174 Chapter 8 Troubleshooting without diagnostics