Need help with USB ports

[creatip123]

Hello there,

 

Recently I've started having a problem with my USB ports. I'm using an old mobo, the ASUS m5a78lmlx (without plus). I've been using it for 2 going 3 years now. So recently I just noticed there's something wrong with my back USB ports (the ports that are actually on the motherboard). I took my digital multimeter, and measured the voltage. They are measured at 9V!! I literally fried 3 of my USB mouses (I'm using the 4th now). All 4 of the back USB ports report the same voltage. Sometimes it would drop to 7 something Volt, but still too much, isn't it? Funny thing is, the front USB ports (the ones on the casing) still read at normal 5V. Other than that, everything seems to be fine (running windows, etc, no problems)

 

I can't RMA it, because it's past the warranty time. So any ideas or suggestions on what I should do? Or is it simply the end of my mobo's lifespan?

 

Thank you in advance.

[xox]

I'd test the 24 pin power connector which goes into your motherboard.

 

1. Unplug the 24-pin and the CPU power from the motherboard
2. Put the negative multimeter wire into the ground (black) wires into the 24-pin and set it so that it can read up to 20 volts (approx) DC
3. Bridge the green wire to any black wire, flick switch on the back of your power supply
4. Measure all yellow, orange and red wires. The red wire should measure 5.5v ish, the yellow wire should measure 12v ish and the orange wire should measure 3.3 volts ish.

 

If this test shows everything is OK, then it is a motherboard problem, in which case, you could either get a new one or sit out the storm for now.

[creatip123]

I'd test the 24 pin power connector which goes into your motherboard.

 

1. Unplug the 24-pin and the CPU power from the motherboard
2. Put the negative multimeter wire into the ground (black) wires into the 24-pin and set it so that it can read up to 20 volts (approx) DC
3. Bridge the green wire to any black wire, flick switch on the back of your power supply
4. Measure all yellow, orange and red wires. The red wire should measure 5.5v ish, the yellow wire should measure 12v ish and the orange wire should measure 3.3 volts ish.

 

If this test shows everything is OK, then it is a motherboard problem, in which case, you could either get a new one or sit out the storm for now.

 

 

Hey, thanks for your response. Tried everything you wrote, and I got normal readings from all the wires. I guess I'm out of luck then, it's my mobo after all. Right now (after all are re-connected), I measured the USB ports again, and it's 7.25V. Very frustrating. Any idea what the cause is? Blown capacitor, or resistor, or something?

[xox]

Hey, thanks for your response. Tried everything you wrote, and I got normal readings from all the wires. I guess I'm out of luck then, it's my mobo after all. Right now (after all are re-connected), I measured the USB ports again, and it's 7.25V. Very frustrating. Any idea what the cause is? Blown capacitor, or resistor, or something?

Very likely a problem with one of the resistors. I guess you are very much out of luck, I've never actually seen that problem before