iFixit - Answers With Device "Mac Desktop"

iMac Intel 27" EMC 2546: USB Refuses to Work Past EFI After CPU and SSD Upgrade

Wed, 26 Aug 2026 05:07:48 -0700

I recently upgraded by iMac from an i5-3470S to an i7-3770 and added an OWC SSD into the unpopulated slot (it had a 3TB HDD originally which is still present and plugged in.) after booting it up everything was normal, mouse and keyboard turned on, worked great, but the moment it pops into ANY OS it kills power to USB and it doesn't seem to see my Bluetooth keyboard either. it's running the latest version of macOS it supports which is catalina and has the base Nvidia GPU.

It gets into the OS itself just fine, like I can see it working on the screen and it looks perfect, I just have no way to interact with the machine. Weird bit it that it's the same when I hop into recovery and internet recovery, keyboard and mouse are working the whole time it downloads internet recovery but when it actually starts to boot it they cut power. I tried resetting everything back to the factory config but the same issue happens.

I have tried cmd+option+P+R on boot to no avail (it does actually reset because in EFI the mac sees and uses the input devices just fine.) I have tried linux too but when it starts the USB boot, as you may guess, it cuts power to the USB ports and fails to boot. I don't have any thunderbolt 2 cables laying around but I am sure I can order some off ebay or something

I know all my bits work because the machine boots with ZERO errors so I don't understand why it would do this and then continue even after I put everything back how it was. Any ideas?

⟐ Commented August 26, 2026 at 5:07 MST

Mac mini M2: Can I Fix my mac mini m2?

Wed, 12 Aug 2026 09:58:57 -0700

I bought a broken mac mini m2 for trash price. It seems the power went out whilst I was updating. It turns on, but the screen doesn’t come up and the light on it is constantly flashing red. I have a second Mac device; when I try to enter Recovery Mode using that, I put my Mac mini into DFU mode, but during the installation process I get the error: ‘Unexpected device state: “DFU” expected “RestoreOS” (Probably forced into DFU mode externally)’. When I took it to a Mac repair shop, they said there was a motherboard fault caused by the power cut. Can I repair this myself?

iMac Intel 27" EMC 2546: iMac won't start. Late 2012 27" 3.4 i7

Tue, 11 Aug 2026 00:27:06 -0700

Is there a check list for trouble shooting a start up issue?

I replaced the power supply but no luck (ebay working pull). I am considering replacing the power button next.

It is a 27" 3.4 i7 with 32gb ram and 2gb Vram. Nothing happens when the start button is pressed. It stopped working in February. There were a few crashing that seemed to be related to connecting to wifi before it stopped working.

▪︎are start buttons known for going out?

I'm going to pull the drive and put it in a laptop for the time being: Look at crash report.

Case is still open: monitor is attached but only taped close.

Also if this does start can it run off an external monitor without the screen attached?

It might be easier to work on that way.

Thanks for any help.

iMac Intel 27" EMC 2429: Are there multiple iterations of the 2011 iMac 27in?

Fri, 05 Jun 2026 18:46:38 -0700

I have two 2011 iMacs both 27in, yet I took them apart and the logic board and screen connectors are different. Any ideas on why this is? My screen identifiers are (SD)E3 and (SD)A2 if that helps. They are both A1312 iMac models.

⟐ Edited by author June 05, 2026 at 18:46 MST

Mac Pro 2009-2012: No audio after upgrade to HD 5770

Sat, 02 May 2026 18:24:21 -0700

Upgraded to radeon hd 5770 did pram reset, DVI instead of mini DP and still not working please help

iMac Intel 21.5": Replacing my ssd drive

Sun, 05 Apr 2026 10:21:47 -0700

My drive is dead. How easy is it to replace (or is it worth replacing)? If I do replace it, can I restore my system from a backup of the drive or do I need to install a new operating system on the new drive? It is a 21.5 “ 2.7GHz Intel i5.

iMac: I have no sound in chrome on my iMac

Sat, 04 Apr 2026 05:38:11 -0700

I currently have no sound in Chrome on my IMAc at startup

⟐ Commented April 04, 2026 at 5:38 MST

iMac Intel 27" EMC 2546: Help identify the pinout of the PSU (A1419, EMC 2546)?

Thu, 26 Mar 2026 17:18:53 -0700

Hi all, I am trying to do a monitor conversion and hoping to reuse the PSU. The model number is ADP-300AF T. It has 3 connectors, other than the AC input.

One big 12 pin molex connector connected to the logic board.
One small 2 pin connector connected to the power button.
One small 7 pin connector, connected to the logic board via a flat cable.

The big 12 pin molex connector is apparently the 12V rail. It's also confirmed by the schematic.

The 2 pin connector for power button is probably a passthrough to the logic button. The PSU usually needs a PS_ON pin to be pulled to the ground to keep on, if it's like an ATX PSU.

The 7 pin connector probably has that PS_ON pin, along with some other pins. I'm trying to figure out their functions. According to the schematic, they are:

PWR_BTN_R
GND
SMC_ACDC_ID_R
TSNS_ACDC_N
TSNS_ACDC_P
GND
BURSTMODE_EN_R_L

So, it confirms my suspicion about the power button. Pin 1 must be the power button pass-through. I looked up burst mode, which I probably don't need to worry about. But I'm unclear about the rest 3:

SMC_ACDC_ID_R
TSNS_ACDC (Positive and Negative)

Can someone shed some light on them?

P.S. does anyone know what kind of connector it is? I hate cutting the original cable. Worst case, I can solder wires to the PCB but it's kinda hard to do with the connector in place.

Schematic:

Connector:

⟐ Commented March 26, 2026 at 17:18 MST

iMac Intel 21.5" EMC 2638: Blade SSD Repair in Fusion Drive and data recovery from HD

Fri, 23 Jan 2026 20:22:00 -0700

I have a problem on my old Late 2013 iMac with 1TB Fusion drive (128gb PCIe x2 Blade SSD + 1TB HD) where the HD is recognize but the SSD is not showing up and because it's a Fusion drive setup the computer won't boot (Just shows ? at boot). I am trying to figure out what my option are for getting the machine back running again. First, I have a Time Machine back but only for up to Oct, 2025 after which the TM drive hot disconnected and never reconnected. So is there a way to recover the missing 2 months of data from the HD drive without the working SSD (serving as a cache drive)? I have a 128GB PCIe x2 SSD from a old 2013 MacBook Air I upgraded that is not being used. Can I use this to somehow restore the Fusion Drive setup and get my missing 2 months of data back? Are there other option for data recovery on the HD? I was able to remove the HD and run Spinrite 6.1 on the drive via a PC and it found no errors with the HD. I can't of course run the SSD without a Mac specific external SSD enclosure due to Apple using a proprietary SSD interface on it's Macs. I going to try and create a bootable external drive with some version of MacOS to see if it detects a internal SSD at all. I should point out that the iMac was running Open Core Legacy Patcher Software on it so I could run a more recent macOS on it then officially supported by Apple (macOS Sonoma) if that makes any difference.

iMac Intel 27" EMC 2390: mini display port replace iMac 27 mid2010

Wed, 31 Dec 2025 04:30:26 -0700

How do I replace the mini display port on my mid-2010 iMac27?and where to find the spare part?

⟐ Commented December 31, 2025 at 4:30 MST

iMac Intel 24" EMC 2134 and 2211: Perché il display rimane scuro?

Tue, 30 Dec 2025 09:59:53 -0700

Perché il display rimane scuro?

Why does the display remain dark?

⟐ Answered December 30, 2025 at 9:59 MST

Mac Pro Late 2013: Seal on inside of lid

Mon, 15 Dec 2025 20:04:29 -0700

I noticed that there is a type of seal running around the inside perimeter of the casing. So when the outer casing slides down onto the main unit, I assume this seal is either to create a cushion for the casing to sit on or its to seal one area of the main unit from another area. Anyway, last time I removed the outer casing, some of this seal was hanging off the casing and was quite brittle and several sections of it came off. Can this be replaced?

iMac Intel 21.5" EMC 3068: Black screen, led 4th and 5th off

Sun, 21 Sep 2025 23:00:47 -0700

Hi, on this imac i have black screen with audio. The second display with a thunderbolt adapter doesn't work, but i don't know if it is a problem of the adapter. On the capacitor near the lvdc cable and on the connector i've the 12v. Where can I search the problem? Thx

iMac Intel 21.5" EMC 2308: Insttalling iFxit power supply, I pulled apart display data connector

Mon, 15 Sep 2025 12:31:49 -0700

Installing iFxit power supply, I pulled apart the display data connector's base. Can this be repaired? What are my options? THANK YOU.

⟐ Commented September 15, 2025 at 12:31 MST

iMac Intel 21.5" EMC 2389: During boot mac shows halfway on loading then does not progress

Sat, 16 Aug 2025 21:45:34 -0700

So recently a customer brought in their Mid 2010 iMac after it lost power on boot, it is now getting to around halfway on post loading and no longer progressing. I thought it would be a corrupt macOS install however I cannot seem to get into recovery mode. Tried about 5 different keyboards, none of them generic apple as neither myself nor the customer have one.

⟐ Commented August 16, 2025 at 21:45 MST

iMac Intel 17": os 3 led acesso e ao liga led power acende e logo apaga

Fri, 25 Jul 2025 14:35:41 -0700

Portuguese: led power ao ligar apaga

English: The 3 LED's access and the power LED turns on and then turns off

⟐ Edited July 25, 2025 at 14:35 MST

iMac Intel 27" EMC 2309 and 2374: Gpu and cpu upgrade

Tue, 22 Jul 2025 20:14:49 -0700

I have an iMac 27" late 2009 cpu dual core 3.06ghz lga 775 can I replace cpu and gpu? And if so, with which models?

⟐ Edited by author July 22, 2025 at 20:14 MST

iMac Intel 27" Retina 5k Display: Can I use late 2014 27” iMac ram in a late 2015 27” iMac?

Mon, 07 Jul 2025 17:23:25 -0700

Hey ifixiters!

I have the oem ram from a late 2014 27” iMac and I want to know if it is compatible with a late 2015 iMac 27”

From some brief reading online, it seems like the 2015 uses a slightly higher hrz ram, it is still ddr3.

Would this work? For example I have used this iMac ram successfully in a 2012 MacBook Pro so I am wondering what the compatibility is.

I’m trying to help out a friend who needs a cheap ram solution and since I have these dimms laying about, I thought I check the compatibility!

Thank in advance!

-M

iMac Intel 27": Display not powering up after SSD swap

Mon, 07 Jul 2025 02:45:01 -0700

I was trying to replace the harddrive (and converting to SSD) on my 2015 iMac. All seemed to be going well but when I tried to turn it on, the monitor panel is completely dead. I hear the strating tone of the computer but no life at all in the panel. Then I noticed one of the display plugs on the motherboard looked like a little piece had broken off. Does that explain why it's not working? And if so is there a fix or have I broken it? If so I might try to just do a monitor conversion.. It's a 2015 so I don't think I need the thermal sensor.. or do I? Any help much appreciated!

⟐ Commented July 07, 2025 at 2:45 MST

iMac Pro: iMac Pro Memory Maxxer RAM Upgrade Kit

Mon, 30 Jun 2025 06:12:50 -0700

Hello!

I want to upgrade memory for my iMac Pro but I'm confused with some details about this memory upgrade kit - as far as I see the original memory module has 288 pin connector but modules in upgrade kit have only 260 pin connectors - how it could be? Will the 260 pin memory module work in 288 pin connector slot?

Best regards,

Denis