Mac Help

[JH]

All of a sudden my Apple Mac computer refuses to turn on if it is plugged in via an extension cable for some reason?

For years it has been in the same place on a desk and using an extension cable as there is no wall socket within reach of the short attached power cable..

Recently it has refused to start up and if I then unplug it and take th unit where there is a wall socket and plug it in directly it works. I have tried several extension cables and these are working with other electrical items - just the Mac that is displaying this issue.

Is there something that I have missed?

 

[er-minio]

First time I hear something like this.
Desktop or laptop? From how you describe the location i suspect an iMac?

 

[sparkplug]

Doesn't sound like an issue with the Mac to me - sounds more like something on your electrical setup.

For the avoidance of doubt, when you plug the Mac in to the wall socket directly, is it the same wall socket that you are then running an extension cord from or a different one?

Does the power cable for the Mac have a transformer somewhere along its length? If so are the cables to/from the transformer something you can unplug/plug back in to make sure it's not a loose connection there?

 

[JH]

First time I hear something like this.
Desktop or laptop? From how you describe the location i suspect an iMac?

Desktop -iMac - the wall socket in question works with other items plugged into it directly and into the extension lead? The wall socket I've used to work on the iMac is a different one as I needed to have the Mac on a table top to use as it has work books on it I needed to complete accounts on today. I've just finished them.

Nothing obvious on the Mac cable either transformer or looking loose. It is very weird - I tried several extensions cables as well.

 

[er-minio]

Have you tried another Mac power cable - or any compatible one? Depending on the age of the iMac... the older models would use the "kettle lead" cables with the trapezoidal female connector on the Mac end. Fairly common.

From the (somehow limited) Mac knowledge I do have, there should be nothing that would prevent you to use extensions (I can take a picture of the mess under my desk as an example ) but there is maybe some non visible damage to the cable, or connectors, that creates some voltage drop or something? Testing another one would be the first thing I'd do after testing other extensions, as you already did.

Sorry I can't be of any help apart from this.

 

[sparkplug]

yeah - if there's power to the extension, and power coming out of the extension and other stuff works when plugged into the extension then the issue lies further down the line.

That leaves the Mac cable or the Mac itself.

I'm in agreement with the right honourable member for London/Rome that the next thing is to try a different power lead from the (known working) extension to the Mac.

I'll be really interested to know what this turns out to be in the end - really unusual one....

 

[phil5849]

I have a new iMac (2024) that has a separate power unit plugged into the wall socket then cabled to the iMac. I have found if I switch the power on at the wall and instantaneously press the on button on the iMac it will not start up. I guess the transformer power box has some fancy anti surge wizardry that only allows the power unit to power the iMac when it has stabilised its output power for the iMac. If i turn it on at the wall and leave it for about five seconds the iMac starts straight away. I have no real idea as to why this happens but that is my best guess.

 

[er-minio]

Oooh right! The new iMacs have external power bricks. I completely forgot.