2014 iMac suddenly not working with wired keyboard

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Level 1

4 points

2014 iMac suddenly not working with wired keyboard

Okay, this has me boggled. Had the iMac for a year, no problems. Used the same wired keyboard, admittedly Windows-style, for that year, no problems. Moved to a new place last night and set up the computer and the keyboard even worked then to allow me to punch in the password and new Wifi info, all that. Now this morning, I go to plug in the login password. No response. wired mouse is working perfectly. I plug the mouse into every port, works instantly. I try plugging the keyboard into every work, no go at all. I then plug the keyboard in my separate MacBook and it works like a charm. So the keyboard is fine, the USB ports are fine because the mouse works with them, the iMac will recognize either of two mouses, but not the keyboard. In fact, eventually it did start recognizing the keyboard in only the volume buttons. They would sporadically click themselves mute/volume down etc. Then I noticed that it would recognize my clicking of only those three buttons, but I was fighting against some ghost clicks. Then I actually noticed that I didn't even have to "click" the buttons, just the physical energy presence of my hand near the buttons would cause the, to "fire". Weird! So I start thinking about power source, but both the iMac and the tester MacBook are plugged into the same surge protector on the same outlet. I can't even login because I can't type anything. Apple should really have a "click keyboard" feature already installed. That should not be something that the user has to think of ahead of time and prep for, a bit ridiculous. Anyway, sorry this is long but it was needed to explain all the details of what I've already tried. Suggestions?

iMac 27″, macOS 10.15

Posted on Dec 12, 2021 9:57 AM

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Answer 1

Top-ranking reply

Will_G_Astro

Level 3

590 points

Dec 12, 2021 8:55 PM in response to Will_G_Astro

I should of added (and it’s too late to edit my previous answer) that although the keyboard works when plugged into your MacBook but not when connected to your iMac does not prove 100% that the keyboard is ok.

There are some differences in the USB hardware applicable to the different ages and technologies used in the iMac and MacBook that may have slightly different tolerances to fault conditions.

Bottom line, the only way to be sure that the keyboard itself is not faulty is to check the iMac with another wired keyboard.

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Answer 2

Dec 12, 2021 1:27 PM in response to vinyinnyincy

First thing to check, and this is important, have an electrician check your mains supply wiring, at the very least move the iMac temporarily to a different building or different power distribution ring and test again there.

Problems with “ghost” activation of a standard wired keyboard when you move your hand over it may be caused by underlying problems with live, neutral and ground wiring reversal or missing ground or faulty neutral wiring to the mains socket of your iMac

The surge protector you are using may or may not have fault indicators which can warn you of missing or reversed connections in the mains supply and it is not unknown for surge protectors to go faulty.

Your MacBook is effectively isolated from the mains supply by its battery and charger so the fact that the keyboard works on the MacBook but not on the iMac is a possible indication of a mains supply problem.

If using a wireless router position it away from the keyboard and do not place mobile phones adjacent to keyboards, the wireless signal from the router and regular “heartbeat” chirp from mobiles can interfere with wired keyboard operation.

If situated in a block of apartments move the iMac to a different location, one of your neighbours may be operating a device that is producing a strong radio frequency signal close to where you have placed the keyboard. Faulty microwave ovens and super-strength WiFi routers are common sources of wired keyboard interference.

Final suggestion, temporarily connect a different keyboard and carry out a NVRAM/PRAM and SMC reset for your iMac according to the model.

https://support.apple.com/en-us/HT204063

https://support.apple.com/en-us/HT201295

HTH.

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Answer 3

vinyinnyincy Author

Level 1

4 points

Dec 12, 2021 10:14 PM in response to Will_G_Astro

So I bought a $4 used MacAlly from Goodwill. Plugged it in and it worked, without changing any outlet arrangements (yet). Then I got curious and plugged in the old keyboard with the new and they both worked fine simultaneously. Then I unplugged the new and left the old one to see if it had recovered and sure enough, after a minute or so it went back to ghost clicks. I took it away entirely and am now punching away on the new one, which seems to be acting normal. So still not sure if something is wrong with the keyboard for sure, or if there is some funny business with the wiring in this room. But thanks for the suggestions!

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2014 iMac suddenly not working with wired keyboard

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