This means that all the 12V and 5V cables are not connected to the same 'source' of power. Multiple rails mean that the 12V and 5V are connected to different groups of transistors. I has many rails / I has one rail, what does that mean? If more than that is required it will fry the transistors connected to that rail or simply wont supply enough power at all. Each rail has a particular amount of max current that can flow through it. This is the long line of 12V and 5V cable that powers your peripherals like HDD, fans ODDs SSD, lights, and even powers GPUs etc. I use 2K ohm, which means it measures till 2K ohm.Ģ.3 The Concept behind this Test(please read) Alternatively select the resistance measuring mode. it looks like the symbol of a buzzer or has the symbol of a diode.Ģ. If there is a connectivity testing mode, select it. You dont need the PSU powered on for this test.ġ. Remove the power cable and screws connecting the PSU to the chassis and motherboard. This means its safe to disconnect the PSU jacks from the mother board now.Ĥ. There probably is some LED on you motherboard which goes off after you turn the power off. Turn off the power to the PSU (not the PSU switch)ģ. YOU DO NOT NEED TO OPEN YOU PSU FOR THIS!!! DONT TOUCH THAT SCREW DRIVER!Ģ.

Not really used, but always good to keep this handy. You will need this to short the 14th(green) and 16th(black) wire of the ATX motherboard connector to switch the PSU on manually.Īlternatively you can bend a suitable length of 1mm thick copper wire/ or a paper clip to do this. '1 with a left indent' means infinite resistance = not connected. OR just use the resistance measuring mode.

Just in case you do get a multimeter, make sure it can measure at least 20V and has the connectivity testing feature which makes a *beep* if theres is a connecting path between the multimeter terminals

Speccy psu