Power supply tester functions

[acenyc]

I purchased one of those $10.00 power suplly testers on amazon, and it seems to work okay. There's an indicator on it that says, SVSB. What does that mean?
Thanks

 

[drescherjm]

I expect it is really 5VSB meaning +5V stand by. My recommendation is to use the $10 tester only to turn on the supply and apply a minimal load. Then test the actual voltages yourself with a digital volt meter.

 

[larrymoencurly]

I once tried a cheap PSU tester, and it said everything was fine, despite the fact the +12V rail was too low to make the hard disk spin.

A $3 Harbor Freight digital multimeter and a bent paperclip make a better tester, and it can test a lot more than just an ATX PSU.

 

[acenyc]

Thanks for the tip. I'll try it. One question, how do I apply a load to the tester?

 

[Jorona]

Thanks for the tip. I'll try it. One question, how do I apply a load to the tester?

Buy a 12v load and attach it to the yellow and black on a molex. We have a coil at my shop that turns out to be about 13a at 12v that we use with a shitty power supply tester to actually have a load on the PSU.

 

[acenyc]

Thanks for the info. I'm kind of new to all this, can you tell what I should buy that would be a 12v load? Thanks again.

 

[larrymoencurly]

how do I apply a load to the tester?

One way is with a motherboard, the other way is with resistors connected between ground and each voltage rail. Resistors rated for 5W or 10W are kind of cheap.

amps = volts / ohms

watts = volts X amps

But the watt rating should be at least 2x - 3x that value, or else it will get hot enough to melt and burn stuff.

So if you hook a 10 ohm resistor to the 12V rail, it will load it down by 1.2 amps, and the power will be 14.4 watts, meaning the resistor should be rated for at least 28.8 watts to be safe.

 

[acenyc]

One way is with a motherboard, the other way is with resistors connected between ground and each voltage rail. Resistors rated for 5W or 10W are kind of cheap.

amps = volts / ohms

watts = volts X amps

But the watt rating should be at least 2x - 3x that value, or else it will get hot enough to melt and burn stuff.

So if you hook a 10 ohm resistor to the 12V rail, it will load it down by 1.2 amps, and the power will be 14.4 watts, meaning the resistor should be rated for at least 28.8 watts to be safe.

I really appreciate all the help, but like I said, I don't have a lot of experience doing these things. How do I use the power supply tester with the 12v aux. and the P1 connected to the motherboard ? I do know how to calculate and test for amps, watts and volts.
Thank you.

 

[larrymoencurly]

How do I use the power supply tester with the 12v aux. and the P1 connected to the motherboard ?

You don't, unless it's wierd one that can be inserted inline between the PSU and motherboard.

If the PSU has only a single +12V rail, then the readings between the 24-pin connector's yellow and black wires will be the same as those on the aux connector. But with multiple 12V rails you'll have to measure the aux connector's voltage separately.