iMac G3 keyboards won't work properly with late 2014 5K iMac

[mackcat]

There is a strange issue occurring when I try to use old iMac G3 keyboards (Model M2452) with a late 2014 5K iMac 27” running Big Sur 11.2.3. I have a few of these keyboards, and they have worked with every computer I have ever used them with, Mac or PC, new or old, with the sole exception of this iMac.

When I plug them in to any of the USB ports, the caps lock light flashes once, dimly, but they do not function at all. They appear as expected in System Information, but they simply do not work.

I tested them on this iMac booted from an Ubuntu flash drive, and they work fine on Ubuntu. I just had the idea to test one of them on MacOS plugged into an Anker USB 3.0 hub, and to my great surprise, it works perfectly!

Do I really have a need to use these keyboards with this iMac? No. I would just love to figure out what is causing this problem, and if anyone else who happens to have this same computer and keyboard is able to replicate it. What on earth would cause a keyboard to malfunction in MacOS, yet work perfectly on the same computer using Ubuntu or when plugged into an external hub? The only thing I can really think of is a glitch in MacOS.

Thanks!
Ben

 

[Slartibart]

Is the the keyboard with the iPad ntegratedpower on-button? That it works with the hub indicates that it seems to draw to much power compared to the specs so the iMac will disable it. The hub on the other hand can probably handle The slightly higher voltage demand.

 

[mackcat]

Is the the keyboard with the iPad ntegratedpower on-button? That it works with the hub indicates that it seems to draw to much power compared to the specs so the iMac will disable it. The hub on the other hand can probably handle The slightly higher voltage demand.

It's not an iPad keyboard, but it does have the integrated power button (only works with Macs of that era). The USB hub is not powered, so while that's a good guess, I don't see how that could be the case in this instance.