03-02-2018, 12:06 PM
If this unit really is an ATX power supply, why on earth are you trying to fix it? ATX power supplies can be found for less than £20.
But no ATX power supply that I'm aware of provides 50V or +/-7V, so I assume that it's not an ATX power supply at all. Please clarify this, because this is very misleading. I will remove "ATX" from the thread title if appropriate.
Please also do us the courtesy of linking to the thread on UKVRRR. Not all of us are members there, and not all of us want to have to search for it. Before any of us here respond, we do need to see what you've already been told so that we're not wasting our time repeating advice.
In other words, help us to help you.
As a rule, putting a voltmeter across the primary of the transformer in a switched-mode power supply is a rather dangerous thing to do. Depending on the topology used, there could easily be spikes on that primary of over 1000V. Not a nice way to treat a DVM, and it could also upset the operation of the supply. Don't! If you must check a switched-mode power supply "live", then you need an isolation transformer and an oscilloscope - and if you wish to probe the waveform on the primary of the transformer, you need x100 probes rated to a couple of thousand volts. It's far safer to put the 'scope across one of the secondary windings.
But no ATX power supply that I'm aware of provides 50V or +/-7V, so I assume that it's not an ATX power supply at all. Please clarify this, because this is very misleading. I will remove "ATX" from the thread title if appropriate.
Please also do us the courtesy of linking to the thread on UKVRRR. Not all of us are members there, and not all of us want to have to search for it. Before any of us here respond, we do need to see what you've already been told so that we're not wasting our time repeating advice.
In other words, help us to help you.
As a rule, putting a voltmeter across the primary of the transformer in a switched-mode power supply is a rather dangerous thing to do. Depending on the topology used, there could easily be spikes on that primary of over 1000V. Not a nice way to treat a DVM, and it could also upset the operation of the supply. Don't! If you must check a switched-mode power supply "live", then you need an isolation transformer and an oscilloscope - and if you wish to probe the waveform on the primary of the transformer, you need x100 probes rated to a couple of thousand volts. It's far safer to put the 'scope across one of the secondary windings.
