Troubleshooting Power Supplies

Power Supplies
There are two common types of power supplies (aka PSU), AT and ATX. AT has 2 system board connectors, and power is manually turned on by hand. ATX has 1 system board connector, and power can automatically be turned on. AT power supplies only work with AT motherboards and ATX power supplies only work with ATX motherboards. With ATX motherboards and power supplies allows automatic power on and off at desire times or wake-on events. Power supplies have no serviceable parts!

Testing the Power Output of the Power Supply
In order to test a power supply the computer must be on and tested by a Multimeter. CAUTION: Before turning on the computer or power supply–the power supply must be connected to a load (like the motherboard) or serious damage, or injury may occur. A good power supply will read +/- 5% of acceptable range. However, even if measured voltage is within the appropriate range, a power supply can still be causing problems. This is because problems with the power supply often come and go. In other words, if the voltages are correct, suspect the power supply to be the problem when certain symptoms are present.

Power Supply Voltage Range

Troubleshooting Power Supplies
The following might have to do with the power supply failing:

• The PC sometimes halts during booting. After several tries, it boots successfully.
• The computer stops or hangs for no reason.
• Data is written incorrectly to the hard drive.
• The system board fails or is damaged.
• Error codes or beep codes occur during booting, but the errors come and go.
• Memory errors appear intermittently.
• The keyboard stops working at odd times.
• The power supply overheats and becomes hot.