Dead iMac and out of ideas- full details in post

[pchc_lx]

Hello, new user here and hoping I could get some suggestions on a really tough hardware problem. Here are the details.

Machine: Apple iMac 21.5-Inch "Core i5" 2.7 (Late 2013) ME086LL/A - iMac14,1 - A1418 - 2638

Synopsis: iMac will not power on after completing several upgrades / part replacements


Original symptoms prompting the upgrade

• iMac works OK, but runs slowly and occasionally “dies”.
• This is an intermittent power / wake problem
• After going to sleep, iMac would be unable to power on.
• No combination of power button / keys would wake or boot iMac
• Only temporary solution: to leave unplugged for an amount of time and try again

Initial repair/upgrade attempt

• Replaced HDD with SSD (with this kit from OWC)
• Repaced 2x4GB RAM w/ 2x8GB RAM (with these RAM sticks)
• Replaced PSU with new PSU (with this new PSU)

(few photos of the process here)

Put everything back together and hit the power button. Nothing.

Machine will not power back on after repairs/replacements.

It booted once, randomly (?!) after indeterminate changes.

I manually shut computer down (*regret doing this*), never started again.

Diagnosis / Troubleshooting attempts

• Replaced HDD with SSD→ Reverted this, old HDD back in
• Repaced 2x4GB RAM w/ 2x8GB RAM→ Reverted this, old RAM back in
• Replaced PSU with new PSU→ Attempted revert, no change, new PSU back in
• Replaced BR2023 mobo Battery w/ new CR2023 (might as well try?)
• Reseated all the above components, plug/unplug, re-seat RAM etc
• Many, many, many combinations of the above

Description of current state

• iMac will not power on nor boot, nor make the boot chime noise
• Screen stays black, does not light up. No beeps. Sometimes I can hear a very faint click sound when pressing the power button.
• Startup key combinations seem to have no effect (difficult to know w/ wireless keyboard though- I’ve tried a mini USB PC keyboard w/ no noticeable effect). This means all the Reset NVRAM/PRAM/SMC processes seem not possible.
• I can force the iMac into a “Fans on High” state by holding power button down while plugging in the IEC cable
• The above implies that the PSU is not dead and the fans at least can power on
• But no other signs of life from the machine whatsoever

I have been working off a mental list of 'things I haven’t tried yet' and going through them one at a time. I’m afraid I am at the end of that list. The only things I can think of

• The motherboard (logic board) is “fried” or dead somehow, I’ve never seen this actually happen to a computer but maybe it does actually happen ?
• I somehow broke something (?) while doing the repairs, I don’t know what it would be, I’ve visually inspected every connecting ribbon cable and component and seen no damage, I experienced no static discharges at any time, I’ve done this before on PCs and Linux computers many times … also annoying that current state is not *thatdifferent from original intermittent issue state
• Some unknown Apple-specific angle that I am unaware of as this is my first time working on an Apple computer. e.g. *"you'd never know this unless someone told you but an iMac won't boot unless ___ (tiny thing easily missed)"*

I’m at the point where I think I just have to bring it into a computer repair service, as I think this may be beyond me. Frustrating situation.

If there is anything else I can try here I would love to know, thanks in advance

 

[rpmurray]

I'm not trying to be funny here, but have you tried replacing the power cable? Also, unplug the iMac, hold the power button for 10 seconds then release it, then try plugging it back in and starting it.

 

[ignatius345]

Hello, new user here and hoping I could get some suggestions on a really tough hardware problem. Here are the details.

Machine: Apple iMac 21.5-Inch "Core i5" 2.7 (Late 2013) ME086LL/A - iMac14,1 - A1418 - 2638

Synopsis: iMac will not power on after completing several upgrades / part replacements


Original symptoms prompting the upgrade

• iMac works OK, but runs slowly and occasionally “dies”.
• This is an intermittent power / wake problem
• After going to sleep, iMac would be unable to power on.
• No combination of power button / keys would wake or boot iMac
• Only temporary solution: to leave unplugged for an amount of time and try again

Initial repair/upgrade attempt

• Replaced HDD with SSD (with this kit from OWC)
• Repaced 2x4GB RAM w/ 2x8GB RAM (with these RAM sticks)
• Replaced PSU with new PSU (with this new PSU)

(few photos of the process here)

Put everything back together and hit the power button. Nothing.

Machine will not power back on after repairs/replacements.

It booted once, randomly (?!) after indeterminate changes.

I manually shut computer down (*regret doing this*), never started again.

Diagnosis / Troubleshooting attempts

• Replaced HDD with SSD→ Reverted this, old HDD back in
• Repaced 2x4GB RAM w/ 2x8GB RAM→ Reverted this, old RAM back in
• Replaced PSU with new PSU→ Attempted revert, no change, new PSU back in
• Replaced BR2023 mobo Battery w/ new CR2023 (might as well try?)
• Reseated all the above components, plug/unplug, re-seat RAM etc
• Many, many, many combinations of the above

Description of current state

• iMac will not power on nor boot, nor make the boot chime noise
• Screen stays black, does not light up. No beeps. Sometimes I can hear a very faint click sound when pressing the power button.
• Startup key combinations seem to have no effect (difficult to know w/ wireless keyboard though- I’ve tried a mini USB PC keyboard w/ no noticeable effect). This means all the Reset NVRAM/PRAM/SMC processes seem not possible.
• I can force the iMac into a “Fans on High” state by holding power button down while plugging in the IEC cable
• The above implies that the PSU is not dead and the fans at least can power on
• But no other signs of life from the machine whatsoever

I have been working off a mental list of 'things I haven’t tried yet' and going through them one at a time. I’m afraid I am at the end of that list. The only things I can think of

• The motherboard (logic board) is “fried” or dead somehow, I’ve never seen this actually happen to a computer but maybe it does actually happen ?
• I somehow broke something (?) while doing the repairs, I don’t know what it would be, I’ve visually inspected every connecting ribbon cable and component and seen no damage, I experienced no static discharges at any time, I’ve done this before on PCs and Linux computers many times … also annoying that current state is not *thatdifferent from original intermittent issue state
• Some unknown Apple-specific angle that I am unaware of as this is my first time working on an Apple computer. e.g. *"you'd never know this unless someone told you but an iMac won't boot unless ___ (tiny thing easily missed)"*

I’m at the point where I think I just have to bring it into a computer repair service, as I think this may be beyond me. Frustrating situation.

If there is anything else I can try here I would love to know, thanks in advance

This sounds something like an issue I had with my 2014 iMac 5K. I'd opened it up last summer to pull out the mechanical HDD and replace it with an SSD. I used a kit from iFixit which worked quite well.

A few weeks thereafter, I started getting random and spontaneous shutdowns. No warning, just a hard power off, and I'd have to unplug the power cable and plug it back in before it would reboot.

Thinking I'd screwed up something inside, I took it to repair place and left it for a while. They left it running for a week and never saw it shut down the way it had for me. Their advice was to double check my USB stuff and power strip. I replaced both (the power strip was pretty old and I had a cheapish USB multi-port splitter attached) and the problem never came back.

In your case (and mine, really) it's a fairly old and not very expensive machine to replace. I'd get it looked at professionally but honestly if it's more than a few hundred bucks to fix you're probably better off getting a used iMac and moving on.

 

[pchc_lx]

I'm not trying to be funny here, but have you tried replacing the power cable? Also, unplug the iMac, hold the power button for 10 seconds then release it, then try plugging it back in and starting it.

Thanks for the response- not a silly suggestion at all. I hope my solution is ultimately something left-field like this but sadly yes- I have tried different IEC power cables. Tried the 10sec unplugged approach too. Usually try a handful of these button/cable combinations each time I swap a component.

This sounds something like an issue I had with my 2014 iMac 5K. I'd opened it up last summer to pull out the mechanical HDD and replace it with an SSD. I used a kit from iFixit which worked quite well.

A few weeks thereafter, I started getting random and spontaneous shutdowns. No warning, just a hard power off, and I'd have to unplug the power cable and plug it back in before it would reboot.

Thinking I'd screwed up something inside, I took it to repair place and left it for a while. They left it running for a week and never saw it shut down the way it had for me. Their advice was to double check my USB stuff and power strip. I replaced both (the power strip was pretty old and I had a cheapish USB multi-port splitter attached) and the problem never came back.

In your case (and mine, really) it's a fairly old and not very expensive machine to replace. I'd get it looked at professionally but honestly if it's more than a few hundred bucks to fix you're probably better off getting a used iMac and moving on.

Appreciate the context here. I wonder what this shutdown behaviour is we've both seen. I'm running mine w/o any peripherals and swapping IEC cables occasionally to test so unfortunately I don't think it's a USB/attached device issue. You make a good point about age of the machine. I had assumed these were still somewhat pricey due to how nice the display is. I checked prices for a new Logic Board but that would be quite the undertaking to swap in. I wonder if it makes more sense just to find a refurb iMac that's a bit more recent. Sucks to have spent the ~$200ish on parts if so. Will weigh my options..

 

[profcutter]

Just a thought, have you tried to check the new PSU to see if it’s functioning? Put a voltage tester to the leads to make sure it’s putting out the right voltage? You could have gotten a new crappy PSU, it happens sometimes.

 

[pchc_lx]

Just a thought, have you tried to check the new PSU to see if it’s functioning? Put a voltage tester to the leads to make sure it’s putting out the right voltage? You could have gotten a new crappy PSU, it happens sometimes.

That's a good suggestion, I think I have a tester somewhere but am a little unsure of how to use it. I'll try to find an instructional video somewhere. Thanks for the reply-

 

[GoodWheaties]

That's a good suggestion, I think I have a tester somewhere but am a little unsure of how to use it. I'll try to find an instructional video somewhere. Thanks for the reply

You definitely want to make sure the board is getting power. Find where the cable from the PSU goes to the logicboard and ground one lead of your tester on a screw and check all the solder points there. It should be like a double row of 5 or 6 solder points. One will have about 5V when the board is off and when the power button is pressed will switch to 12V. If the board is getting power and still not working it’s probably junk.

 

[profcutter]

Just be careful around the exposed PSU components! Zappo!