M2452 (iMac) keyboard power key circuitry - Does anyone have a picture of this?

[Stupidface]

I am looking for a clear photograph of the specific circuitry that allows this particular keyboard to send the "power key" HID keypress. 

It seems that Apple implemented the "power on" circuitry in this, their first USB keyboard, in an interesting way.  A quarter-century later, I am interested in how it was they went about it. 

Does anyone have (or know where I might find) such a photograph?

[TomahawkLabs]

DeskThority describes it working as:

The power button or key is a soft power control that is wired up as a regular key on the keyboard matrix: the keyboard interface on the motherboard (e.g. ADB) must be left permanently running. As a normal key, it can also be detected by the operating system: many versions of Mac OS display a shutdown dialog in response to this key being pressed.

Is the power button able to turn on the PC from an Off state, or just a hibernate/sleep state?

[Stupidface]

DeskThority describes it working as:

The power button or key is a soft power control that is wired up as a regular key on the keyboard matrix: the keyboard interface on the motherboard (e.g. ADB) must be left permanently running.

I do not claim to be an expert in these matters and am open to correction, but I believe the above is half-right.  Yes, in present day USB-equipped systems, “the keyboard interface on the motherboard must be left permanently running.” 

However, in the particular case of ADB, the keyboard interface does not appear to need to be permanently running.  My understanding is that ADB makes use of a unique PSW (Power Switch) pin which is attached directly to the power supply of the host computer. This pin allows a user to hit the power button on the keyboard to start the machine without the need for the host machine to be in a sleep state.

I believe it is Apple's use of this unique pin that allows people to build projects like this: https://www.instructables.com/Intro-31/

Is the power button able to turn on the PC from an Off state, or just a hibernate/sleep state?

The former: from an off state. 

Rather than implementing USB "remote auto-wakeup" to power on, Apple kept the spirit of the ADB PSW pin. They wired the keyboard's power button to the USB D- signal: pressing this button shorts this signal to ground.  This allows the rest of the keyboard to stay unpowered, apart from the D- pin.

The point to all of this being: the M2452 iMac keyboard is a peculiar, one of a kind hybrid of ADB and USB, hence my interest in it.

I am hoping someone reading this:

A) Has one of these keyboards already in pieces, knows what I am talking about, and need only grab a camera to take a few clear photos of the relevant circuitry.

or

B) Someone has one of these keyboards and it isn’t already in pieces.  However, after reading the above, they are now intrigued enough to be willing to take the keyboard to pieces sometime in the next month or two and take a few clear photos of the relevant circuitry.

Can anyone help?

[TomahawkLabs]

I own several Apple keyboards, but none of them are that model. A quick eBay search shows they go for ~$40 so luckily not too expensive, but hopefully another collector can help.

[Stupidface]

I own several Apple keyboards, but none of them are that model.

From what I understand of Apple lore, Apple stopped building "real" keyboards when they discontinued the Apple Extended Keyboard II in 1995.  By the time the iMac appeared in 1998, Apple keyboards seem to have become more or less an afterthought.

If there is a compelling reason to own an M2452, it isn't leaping to mind.  Apart from people with peculiar ADB fixations (ahem) and completist types who feel compelled to own an example of every keyboard Apple ever made, frankly, I cannot imagine very many people having one of these on hand. 

Having said that, I would like to think if anyone does have one on hand, they are likely to be found here on GH.

A quick eBay search shows they go for ~$40 so luckily not too expensive, but hopefully another collector can help.

Er, I'm not sure I'd want my girlfriend to get wind of my spending $40 to satisfy $20 worth of curiosity (I am in enough trouble already).  But you are right: if no one responds, I can simply buy one and cut it up.

I'd as soon not do that if it can be helped, though.  While I may not think highly of this keyboard myself, I have come across at least one person who swears by the things - so much so, he claims to have typed on nothing but these keyboards for the past two decades. It seems the only reason he ultimately threw in the towel and moved on to a different model of keyboard is that finding reliably working examples of the M2452 is "becoming impossible."

(Should I end up taking one apart, I am afraid it is unlikely to emerge from the experience in reliably working condition.)