Short circuit in output of power supply

[Saeedk9574]

Hello everyone,
My computer power supply is short circuit in the output when I test it by multimeter, although it has all the voltages including 12, 5 and 3.3. So what is the reason of that while it provides these voltages and works without problem, but it is short circuit. Is it dangerous to use it in this way?

 

[KlausST]

Hi,

I can only guess that you did (or expect) something wrong to proove it is short circuit.

Klaus

 

[Saeedk9574]

Hi,

I can only guess that you did (or expect) something wrong to proove it is short circuit.

Klaus

It is not really complex to test short circuit. Simply with continuity mode of multimeter I checked + and - of power output, then surprisingly I heard the beep sound.
can't we say output caps are the reason? If so, do I must to change them although I have the voltage in the output.

 

[KlausST]

Hi,

It is not really complex to test short circuit.

Fair enough.
But a beep sound is a rather coarse way to do a measurement. It follows no standard. Each multimeter has it´s own way to measure and it´s own threshold.
Some test with 10mA, others with 0.1mA, some use a resistor as current limiter... In best case it is written in the manual.

-> It´s better to use a true Ohm-meter and decide on
If the meter shows 0.07 Ohms ... would you call it a short circuit? (Your multimeter surely beeps)

I can tell you I´ve build power supplies to work with loads down to 0.03 Ohms, so 0.07 Ohms is quite an easy to drive normal load for them.

****

You don´t know the exact working operation and thresholds of the multimeter.
You don´t know the exact behaviour of the power supply.

Thus it´s hard to tell whether the power supply is good or not.

Klaus

 

[Gaber Mohamed Boraey]

Not necessary if beep then it’s a short circuit, can be small resistance you measure , or transformer coil

 

[pjmelect]

Computer power supplies have load resistors built into them that can be of low resistance which could cause your meter to beep. If you truly have a short circuit on the output of your power supply it is normally due to one of the bridge rectifier diodes being short, this of course will stop the power supply from working.