Problem turning on iMac 2020 with rear button

[Gmouse]

Got my iMac 2020 last week, and have had no issues with it power wise, and have run diagnostics (Apple and third-party) that show all is well HW-wise. But, twice now, when I've had it shutdown (for more than a few minutes) and tried to turn it on using the rear button...it didn't turn on.

I've held the button up to 30 seconds, with no sign that it's turning on (my iMac 2014 I have to hold ~5-7 seconds then see the screen brighten and the Apple symbol appear).

I finally got it to turn on by pressing the button repeatedly and holding it a few seconds, then finally the screen brightens and the Apple symbol appears.

This has not happened EVERY time (maybe 2 out of 5), and Restarts have had no issues. I did replace the 8 GB of Apple RAM with 128 GB of OWC RAM, and read that the FIRST time you turn it on after upgrading RAM, it will be slow as it has to check the RAM (and it was), but is this causing the issue with turning it on after the first time?

Thanks!

 

[kohlson]

128 GB of OWC RAM, and read that the FIRST time you turn it on after upgrading RAM,

Computers generally do something called Power On Self Test (POST) when they are first powered up. This checks for everything thing it needs before proceeding to load the OS, and then all the various processes and apps. POST signals all is good, on Apple, with the start-up chime. The more there is to check, the longer it takes to get to the chime. While I don't know specifically if the iMac 2020 does this, I would be very surprised if it didn't.
With most Macs, holding down the power button can do different things, like reset SMC.
Question: why don't you just let it sleep/wake?

 

[CWallace]

When you press the button, how long do you press it before you release it and when you release it, how long do you wait for the machine to turn on?

On my 2017 iMac 5K, I press it for a moment (less than a second) and within a few seconds the screen turns on (so it goes from black to a light grey) and around five seconds after that the Apple logo appears and the "boot line" starts drawing across the screen.

 

[Gmouse]

Computers generally do something called Power On Self Test (POST) when they are first powered up. This checks for everything thing it needs before proceeding to load the OS, and then all the various processes and apps. POST signals all is good, on Apple, with the start-up chime. The more there is to check, the longer it takes to get to the chime. While I don't know specifically if the iMac 2020 does this, I would be very surprised if it didn't.
With most Macs, holding down the power button can do different things, like reset SMC.
Question: why don't you just let it sleep/wake?

Thanks. I was actually switching around my old and new computers, so I had turned them both completely off, why I had to turn them back on. Normally, I just leave them on, and they rest or screen goes dark as scheduled, and no issues. Fully aware of POST with Windows, assume Macs have something similar, and having 128 GB RAM could cause it to boot to login slower--however, I assume it at first has to power up, and I'd assume even if I don't see the Apple logo and white progress bar, I should at least see the screen lighten as it gets power? I'd just think, if anything, I'd take longer for the progress bar to complete. Like I mentioned, I was told that the time after you change the RAM side, that forces a diagnostic or something to run, once, and that DID happen, where it took a few minutes--with the Apple logo and progress bar visible.

 

[Gmouse]

When you press the button, how long do you press it before you release it and when you release it, how long do you wait for the machine to turn on?

On my 2017 iMac 5K, I press it for a moment (less than a second) and within a few seconds the screen turns on (so it goes from black to a light grey) and around five seconds after that the Apple logo appears and the "boot line" starts drawing across the screen.

With my 2014, it took longer than "less than a second", I'd say a few seconds up to ~5. Then, got the same thing you describe. I have tried that, holding the button for various lengths of time (up to 30 seconds) and got nothing. But when I pressed it several times in quick succession, it booted...

Thanks!

 

[Mcdevidr]

Mine does something similar for some reason. I have the $2300 base model 2020.

 

[pldelisle]

Mine does something similar for some reason. I have the $2300 base model 2020.

Upgraded RAM ?

 

[MacStreamer]

Do you have "put hard discs to sleep when possible" checked or unchecked? I have mine unchecked and the screen usually pops up after a couple of seconds if I click the mouse or keyboard.

 

[Gmouse]

Do you have "put hard discs to sleep when possible" checked or unchecked? I have mine unchecked and the screen usually pops up after a couple of seconds if I click the mouse or keyboard.

Yes, unchecked. I have all the sleep or wakeup stuff turned off (other than display will go to screensaver then off).

 

[Mcdevidr]

Upgraded RAM ?

Yea my guess is the ram. The machine just seems finicky it’s been running great though.

 

[pldelisle]

Yea my guess is the ram. The machine just seems finicky it’s been running great though.

OWC RAM ?

 

[Mcdevidr]

OWC RAM ?

Yes. I am now running 4x8Gb OWC.

 

[Ruggy]

Hi are you sure you're not being a bit impatient and thus switching the machine off again?
You haven't explained exactly what you've tried so excuse me, but usually it's just necessary to blip the button and wait a few seconds.
If you hold the button down for more than 10 seconds then that turns it off again.

 

[Gmouse]

Hi are you sure you're not being a bit impatient and thus switching the machine off again?
You haven't explained exactly what you've tried so excuse me, but usually it's just necessary to blip the button and wait a few seconds.
If you hold the button down for more than 10 seconds then that turns it off again.

With my 2014 iMac, with 32 GB of Apple RAM, I hold the button for ~5-7 seconds or so, the screen brightens, I let it go, then the Apple logo appears and the white progress line starts. With the 2020 iMac, 128 GB of OWC RAM, I will sometimes see the exact same sequence (I'd say 4/5 of the time) taking the exact same time. But, at times, the screen never brightens, Apple logo never shows. Holding it longer does nothing. Pressing it rapidly a few times, then it turns on.