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quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
Hi All,

I just replaced the NVME in my iMac, but now when I turn it on absolutely nothing seems to happen. No fan noise, no hdd noise, etc.

I don't think I broke the power button, but I tried connecting the pins in the power button connector together to see if that helped. No dice.

Any idea what I could try next? I checked all the connections on the power board and they seem fine... I've done a few Mac repairs before and I felt this one went well so I'm kinda surprised.

I'm currently testing it with the display unhooked, but I did try once with the display plugged in.

Edit: I can hear some "whine" from the power board with the power supply plugged in, but pressing/holding the power button doesn't seem to change the sound at all
 
Last edited:

quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
I'm pretty sure I fried something. It was given to me to free, my backup plan was to turn it into a monitor anyways :p
 

PaulD-UK

macrumors 6502a
Oct 23, 2009
654
299
The PSU when connected to mains power is fully powered on whether or not the iMac's power button is pressed, so the power status lights should be lit if your PSU is making noises.

The power button on/off line seems to be passed straight through the PSU to the logic board through the 7 pin connection flat cable between PSU and logic board, and the logic board passes back the on/off command back to the PSU to put it into standby mode.

So the connector cable between the PSU and logic board is the first thing to check that it is properly connected.

It will make a great monitor if the screen panel is good. ;)
 
Last edited:

quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
The PSU when connected to mains power is fully powered on whether or not the iMac's power button is pressed, so the power status lights should be lit if your PSU is making noises.

The power button on/off line seems to be passed straight through the PSU to the logic board through the 7 pin connection flat cable between PSU and logic board, and the logic board passes back the on/off command back to the PSU to put it into standby mode.

So the connector between the PSU and logic board is the first thing to check that it is properly connected.

It will make a great monitor if the screen panel is good. ;)
Thanks for the reply! I tried reseating the 7-pin connector, still not getting any of the status lights. Do you know if the status lights would light even if something on the mobo got zapped?

The panel looks excellent luckily 😂
 

Significant1

macrumors 68000
Dec 20, 2014
1,637
758
Don't you still need an adapter. I know I had to use an adapter in my 2013 MacBook air.
 

PaulD-UK

macrumors 6502a
Oct 23, 2009
654
299
I would guess that the low voltage output side of the PSU has failed, perhaps a mosfet - maybe caused by a mobo short.
It's quite a noisy PSU, so any noise you are hearing is possibly from the high voltage input circuits or transformer.
But that's a complete guess.

All the other connections to the logic board are peripherals, so the diagnostics LEDs should work normally if there is a connection problem - unless a dead short has damaged the PSU... o_O
 

quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
I tried removing the new nvme+adapter and added the old apple one. Now I get LEDs! testing more
 
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quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
Well I tried reseating the adapter+nvme multiple times, and the issue remains. There is no problem with just the adapter. But I'd be surprised if the NVME is actually the problem.

I think I'm just going to get an OWC drive instead, even though they are overpriced and the computer will have less storage. I might also order another adapter to test that too as the OWC won't be in until Thursday.
 

Jumpthesnark

macrumors 65816
Apr 24, 2022
1,117
4,777
California
Well I tried reseating the adapter+nvme multiple times, and the issue remains. There is no problem with just the adapter. But I'd be surprised if the NVME is actually the problem.

I think I'm just going to get an OWC drive instead, even though they are overpriced and the computer will have less storage. I might also order another adapter to test that too as the OWC won't be in until Thursday.
Any way to test the NVME on a different adapter & computer?
 
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Nguyen Duc Hieu

macrumors 68030
Jul 5, 2020
2,929
970
Ho Chi Minh City, Vietnam
Well I tried reseating the adapter+nvme multiple times, and the issue remains. There is no problem with just the adapter. But I'd be surprised if the NVME is actually the problem.

I think I'm just going to get an OWC drive instead, even though they are overpriced and the computer will have less storage. I might also order another adapter to test that too as the OWC won't be in until Thursday.

If the iMac runs normally when you put the stock nVME back in, then I think you can conclude that the nVME adapter or the combo of nVME +adapter caused the short. What a relief!
 
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iMac2019

Contributor
Aug 3, 2023
32
15
Riviera, France
Maybe you should have a look here :

Many of the available Blade Adapters have their connecter PINS exposed such that when inserted into the Logic board, they short out on the shield of the socket on the Logic board.
So it's highly recommended to cover these pins with Kapton tape.
See examples of what other users have done here and here
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,756
12,863
OP wrote:
"I think I'm just going to get an OWC drive instead, even though they are overpriced and the computer will have less storage"

There's an old saying for doing things like this.
It's called "throwing away good money after bad..."
 
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quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
Maybe you should have a look here :

Many of the available Blade Adapters have their connecter PINS exposed such that when inserted into the Logic board, they short out on the shield of the socket on the Logic board.
So it's highly recommended to cover these pins with Kapton tape.
See examples of what other users have done here and here
Oh good call! I had seen people using Kapton tape but I hadn't seen this was where things were shorting.

I ended up just buying a used OWC Drive off eBay for a really good price, so I'm going to return the adapter/NVME to Amazon as that's easy and seems a bit less sketchy to being bumped etc.

Waiting a bit lets me procure the correct BR 2032 battery instead of a CR, which is good for the longevity of the machine.

Thanks for the advice everyone :)
 
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ignatius345

macrumors 604
Aug 20, 2015
7,220
12,034
I tried removing the new nvme+adapter and added the old apple one. Now I get LEDs! testing more
You might want to take a look through here. Lots of very specific info on which adapters to use, etc.
 

iMac2019

Contributor
Aug 3, 2023
32
15
Riviera, France
Oh good call! I had seen people using Kapton tape but I hadn't seen this was where things were shorting.

I ended up just buying a used OWC Drive off eBay for a really good price, so I'm going to return the adapter/NVME to Amazon as that's easy and seems a bit less sketchy to being bumped etc.

Waiting a bit lets me procure the correct BR 2032 battery instead of a CR, which is good for the longevity of the machine.

Thanks for the advice everyone :)
Very good advice to also change the battery on the motherboard when taking the surgery route.
Unfortunately, I forgot to replace it.
Considering the ever-present risk of breaking something when opening the machine, I'd like to avoid doing it as much as possible as long as the machine is running smoothly.
If it's not broken, don't fix it.
Keep us informed on your hw upgrade ;)
 
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quartzite

macrumors newbie
Original poster
Mar 9, 2020
13
3
The OWC NVMe I bought off eBay arrived today. Computer was able to boot with it, turns out nothing else was wrong :).

I glued it back together and am now installing an OS. Thanks everyone for the help and advice, my partner is looking forward to using the machine with its gorgeous display.
 
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