Apple Imac Late2015 Essentials Manual

							 Chapter 4    Find answers 51
Replace memory
Overview
You can replace memory in the 27-inch iMac by following the instructions in this section.
Important:  The memory in the 21.5-inch iMac is not user-replaceable and can’t be upgraded 
after purchase. The 21.5-inch iMac can have a maximum of 16 GB of memory installed. Do not 
attempt to open your 21.5-inch iMac to replace or upgrade its memory. 
Your 27-inch iMac comes with at least 8 gigabytes (GB) of 1867 MHz DDR3 memory installed as 
two 4 GB memory modules. You can replace or install additional 4 GB or 8 GB memory modules 
for up to a maximum of 32 GB. Use Small Outline Dual Inline Memory Modules (SO-DIMM) that 
meet all the following specifications:
 •PC3-15000
 •Unbuffered and nonparity
 •204-pin 1867 MHz DDR3 SDRAM
WARNING:  Apple rec ommends that you have an Apple-certified technician install memory. See 
More resources, service, and support for information about how to contact Apple for service. If 
you attempt to install memory and damage your equipment, that damage isn’t covered by the 
limited warranty on your iMac.
Install memory
The 27-inch iMac has four memory slots. Two are filled with at least a 4 GB memory module. You 
can install additional memory in the free slots or replace the memory in the filled slots with 2 GB, 
4 GB, or 8 GB memory modules, for up to 32 GB of memory.
You can purchase additional memory from an Apple Authorized Reseller.
WARNING:  Alwa ys shut down your iMac and remove the power cord before installing memory. 
Do not attempt to install memory while your iMac is plugged in. If you’ve been using your 
iMac, wait ten minutes after shutdown to let the internal components cool before continuing.
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Install memory in your 27-inch iMac
 1 Turn off your iMac by choosing Apple menu > Shut Down.
 2 Disconnect all cables and the power cord from your iMac.
 3 Place a soft, clean towel or cloth on your work surface. Hold the sides of your iMac and lay it 
down so that the screen rests on the surface and the bottom faces you.
 4 Open the memory compartment door by pressing the small gray button located just above the 
AC power port.
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The memory compartment door opens as the button is pushed in.
 5 Remove the memory compartment door and set it aside.
A diagram on the bottom of the door shows the orientation of the memory modules and the 
memory cage levers.
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							 Chapter 4    Find answers 53
 6 Locate the levers on the sides of the memory cage. Push the levers outward to release the cage.
 7 Pull the levers toward you to give you access to the memory module slots. 
 8 Remove a memory module—handle it carefully by its edges and pull it straight up and out. 
 9 With the notch on the bottom and toward the right side, replace or install a memory module by 
inserting it into the slot. Press firmly and evenly until you feel a slight click.
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							 Chapter 4    Find answers 54
 10 After you’ve installed all the memory modules, push the memory cage levers down into the 
compartment until they click back into place.
 11 Replace the memory compartment door, then press it firmly.
 12 Hold your iMac by its sides and return it to a standing position. Reconnect the cables and 
power cord.
 13 Press the power button on the back of your iMac to turn it on.
Make sure your iMac recognizes the new memory
After you install memory, check that your iMac recognizes the new memory.
 1 Start up your iMac.
 2 When you see the macOS desktop, choose Apple menu > About This Mac.
You’ll see the total amount of memory installed in your iMac. For a detailed view of the amount 
of memory installed, click System Report, then click Memory on the left under Hardware.
If the memory you installed doesn’t meet specifications, your iMac will sound three tones every 
five seconds. If this happens, shut down your iMac and check the installation instructions again 
to make sure that the memory is compatible and installed correctly. If you still have problems, 
remove the memory and consult the support information that came with the memory or contact 
the vendor who provided the memory.
More resources, service, and support
You can find more information about your iMac in System Report, Apple Diagnostics, and 
through online resources.
System Report. To get information about your iMac, use System Report. It shows you what 
hardware and software is installed, the serial number and operating system version, how much 
memory is installed, and more. To open System Report, choose Apple menu > About This Mac, 
then click System Report.
Apple Diagnostics. You can use Apple Diagnostics to help determine if there’s a problem with 
one of the computer’s components, such as the memory or processor. Apple Diagnostics helps 
to identify the potential source of a hardware issue and provides first steps to try and resolve it. 
Apple Diagnostics will also help you get in touch with Apple Support if you need more help.
Before using Apple Diagnostics, disconnect any external devices, such as a hard disk or external 
display. Be sure your iMac is connected to the Internet.
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To start Apple Diagnostics, restart your iMac and hold down the D key as it starts up. If prompted, 
select the language for your location. Press the Return key or click the right arrow button. The 
basic Apple Diagnostics test takes a few minutes to complete. If issues are found, a description 
of the issue appears with additional instructions. Make a note of any reference codes before you 
exit Apple Diagnostics.
Online resources. For online service and support information, see www.apple.com/support. You 
can learn about Apple products, view online manuals, and check for software updates. Connect 
with other Apple users, and get service, support, and professional advice from Apple.
AppleCare support. If you need assistance, AppleCare representatives can help you with 
installing and opening apps, and with troubleshooting. Call the support center number nearest 
you (the first 90 days are complimentary). Have the purchase date and your iMac serial number 
ready when you call.
Your 90 days of complimentary telephone support begins on the date of purchase.
CountryPhone numberWeb address
United States 1-800-275-2273www.apple.com/support
Australia (61) 1-300-321-456www.apple.com/au/support
Canada 1-800-263-3394English: 
www.apple.com/ca/support
French: 
www.apple.com/ca/fr/support
Ireland 1-800-804-062www.apple.com/ie/support
New Zealand 00800-7666-7666www.apple.com/nz/support
United Kingdom (44) 0844 209 0611www.apple.com/uk/support
Telephone numbers are subject to change, and local and national telephone rates may apply. A 
complete list is available on the web at www.apple.com/support/contact/phone_contacts.html.
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  56
Safety, handling, and support
Important safety information
WARNING:  Failure to follow these safety instructions could result in fire, electric shock, or other 
injuries, or damage to your iMac or other property. Read all safety information below before 
using your iMac.
Handling. Set up your iMac on a hard, stable work surface that allows for adequate air circulation 
under and around the computer. Never push objects into the ventilation openings. Your iMac can 
be damaged if dropped, burned, punctured, or crushed, or if it comes in contact with liquids, oils, 
and lotions. Don’t use a damaged iMac, such as one with a cracked screen, as it may cause injury.
Liquid exposure. Keep your iMac away from sources of liquid, such as drinks, oils, lotions, 
washbasins, bathtubs, shower stalls, and so on. Protect your iMac from dampness, humidity, or 
wet weather, such as rain, snow, and fog. 
Po w e r. Unplug the power cord (by pulling the plug, not the cord) and disconnect the Ethernet 
cable or phone cord if any of the following conditions exist:
 •You want to add memory (you can replace memory yourself only in the 27-inch iMac).
 •The power cord or plug becomes frayed or otherwise damaged.
 •You spill something into the case.
 •Your iMac is exposed to rain or excess moisture.
 •Your iMac has been dropped, or the case has been damaged.
 •You suspect that your iMac needs service or repair.
 •You want to clean the case (use only the recommended procedure, described later in  
this document).
Important:  The only way to turn off power completely is to unplug the power cord. Make sure at 
least one end of the power cord is within easy reach so that you can unplug your iMac when you 
need to.
Power specifications (21.5-inch model):
 •Voltage: 100 to 240 V AC
 •Current: 3 A, maximum
 •Frequency: 50 to 60 Hz
Power specifications (27-inch model):
 •Voltage: 100 to 240 V AC
 •Current: 4 A, maximum
 •Frequency: 50 to 60 Hz
WARNING:  Your AC cor d has a three-wire grounding plug (a plug that has a grounding pin). 
This plug fits only a grounded AC outlet. If you’re unable to insert the plug into an outlet 
because the outlet isn’t grounded, contact a licensed electrician to replace the outlet with a 
properly grounded one. Do not defeat the purpose of the grounding pin.
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Hearing loss. Listening to sound at high volumes may damage your hearing. Background noise, 
as well as continued exposure to high volume levels, can make sounds seem quieter than they 
actually are. Use only compatible earbuds, headphones, or earpieces with your iMac. Turn on the 
audio and check the volume before inserting anything into your ear. For more information about 
hearing loss, see www.apple.com/sound.
WARNING:  To prevent possible hearing damage, do not listen at high volume levels for 
long periods.
Repairing. Your iMac doesn’t have any user-serviceable parts, except for the memory, which is 
user-replaceable in 27-inch models only. Do not attempt to replace or repair any components 
inside your iMac. If your iMac needs service, contact Apple or an Apple Authorized Service 
Provider. If you open your iMac or install items other than memory in 27-inch models, you risk 
damaging your computer. Such damage isn’t covered by the limited warranty on your iMac.
Navigation. Maps, directions, and location-based apps depend on data services. These data 
services are subject to change and may not be available in all areas, resulting in maps, directions, 
or location-based information that may be unavailable, inaccurate, or incomplete. Compare 
the information provided on iMac to your surroundings and defer to posted signs to resolve 
any discrepancies. Do not use these services while performing activities that require your full 
attention. Always comply with posted signs and the laws and regulations in the areas where you 
are using iMac and always use common sense.
Radio frequency exposure. iMac uses radio signals to connect to wireless networks. For 
information about radio frequency (RF) energy resulting from radio signals and steps you can 
take to minimize exposure, see www.apple.com/legal/rfexposure .
Medical device interference. iMac contains components and radios that emit electromagnetic 
fields, which may interfere with pacemakers, defibrillators, or other medical devices. Maintain a 
safe distance of separation between your medical device and iMac. Consult your physician and 
medical device manufacturer for information specific to your medical device. If you suspect iMac 
is interfering with your pacemaker or any other medical device, stop using iMac.
Medical conditions. If you have a medical condition that you believe could be affected by using 
iMac (for example, seizures, blackouts, eyestrain, or headaches), consult with your physician prior 
to using iMac. 
Repetitive motion. When you perform repetitive activities such as typing or playing games on 
iMac, you may experience discomfort in your hands, arms, wrists, shoulders, neck, or other parts 
of your body. If you experience discomfort, stop using iMac and consult a physician.
High-consequence activities. iMac is not intended for use where the failure of the computer 
could lead to death, personal injury, or severe environmental damage.
Explosive atmospheres. Charging or using iMac in any area with a potentially explosive 
atmosphere, such as areas where the air contains high levels of flammable chemicals, 
vapors, or particles (such as grain, dust, or metal powders), may be hazardous. Obey all signs 
and instructions.
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Important handling information
Operating environment. Operating your iMac outside these ranges may affect performance:
 •Operating temperature: 50° to 95° F (10° to 35° C)
 •Storage temperature: -4° to 113° F (-25° to 45° C)
 •Relative humidity: 5% to 90% (noncondensing)
 •Operating altitude: Tested up to 10,000 feet (0 to 3048 meters)
Do not operate your iMac in areas with significant amounts of airborne dust, or smoke from 
cigarettes, cigars, ashtrays, stoves, or fireplaces, or near an ultrasonic humidifier using unfiltered 
tap water. Tiny airborne particles produced by smoking, cooking, burning, or using an ultrasonic 
humidifier with unfiltered water may, in rare instances, enter the ventilation openings of your 
iMac and, under certain conditions, result in a slight haze on the inside surface of the glass panel 
that covers the iMac display.
Carrying your iMac. Before you lift or reposition your iMac, shut it down and disconnect all 
cables and cords. To lift your iMac, hold its sides.
Using connectors and ports. Never force a connector into a port. When connecting a device, 
make sure the port is free of debris, that the connector matches the port, and that you have 
positioned the connector correctly in relation to the port.
Storing your iMac. If you are going to store your iMac for an extended period of time, keep it in a 
cool location (ideally, 71° F or 22° C).
Cleaning your iMac. When cleaning the outside of your iMac and its components, first shut 
down your iMac, then unplug all cords and cables. Then dampen a clean, soft, lint-free cloth to 
wipe the iMac exterior. Avoid getting moisture in any openings. Don’t spray liquid directly on the 
computer. Don’t use aerosol sprays, solvents, abrasives, or cleaners containing hydrogen peroxide 
that might damage the finish.
Cleaning the iMac display. To clean your iMac screen, first shut down your iMac, then unplug all 
cords and cables. Dampen a clean, soft, lint-free cloth with just water and wipe the screen. Don’t 
spray liquid directly on the screen.
Cleaning the Magic Mouse 2. Turn off the mouse, then unplug the cable (if necessary). To clean 
the outside of your mouse, use a clean, soft, lint-free cloth that’s been lightly moistened with 
water. Don’t get moisture in any openings or use aerosol sprays, solvents, or abrasives. 
Cleaning the Magic Keyboard. Turn off the keyboard, then unplug the cable (if necessary). To 
clean the outside of your keyboard, use a clean, soft, lint-free cloth that’s been lightly moistened 
with water. Don’t get moisture in any openings or use aerosol sprays, solvents, or abrasives. 
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Understanding ergonomics
When you use the keyboard and mouse, your shoulders should be relaxed. Your upper arm and 
forearm should form an angle that is slightly greater than a right angle, with your wrist and hand 
in roughly a straight line.
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This
Not this
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Change hand positions often to avoid fatigue. Some computer users might develop discomfort 
in their hands, wrists, or arms after intensive work without breaks. If you begin to develop 
chronic pain or discomfort in your hands, wrists, or arms, consult a qualified health specialist.
Mouse or optional trackpad. Position the mouse or trackpad at the same height as the keyboard 
and within a comfortable reach.
Chair. An adjustable chair that provides firm, comfortable support is best. Adjust the height of 
the chair so your thighs are horizontal and your feet are flat on the floor. The back of the chair 
should support your lower back (lumbar region). Follow the manufacturer’s instructions for 
adjusting the backrest to fit your body properly.
Built-in display. Arrange the display so that the top of the screen is slightly below eye level 
when you’re sitting at the keyboard. The best distance from your eyes to the screen is up to you, 
although most people seem to prefer 18 to 28 inches (45 to 70 cm). 
Position the display to minimize glare and reflections from overhead lights and windows. The 
stand lets you set the display at the best angle for viewing, helping to reduce or eliminate glare 
from lighting sources you can’t move. 
For more information about ergonomics, see www.apple.com/about/ergonomics .
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FCC regulatory compliance
This device complies with part 15 of the FCC rules. Operation is subject to the following two 
conditions: (1) This device may not cause harmful interference, and (2) this device must accept 
any interference received, including interference that may cause undesired operation.
Note:  This equipment has been tested and found to comply with the limits for a Class B digital 
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable 
protection against harmful interference in a residential installation. This equipment generates, 
uses, and can radiate radio frequency energy and, if not installed and used in accordance with 
the instructions, may cause harmful interference to radio communications. However, there is 
no guarantee that interference will not occur in a particular installation. If this equipment does 
cause harmful interference to radio or television reception, which can be determined by turning 
the equipment off and on, the user is encouraged to try to correct the interference by one or 
more of the following measures:
 •Reorient or relocate the receiving antenna.
 •Increase the separation between the equipment and receiver.
 •Connect the equipment to an outlet on a circuit different from that to which the receiver 
is connected.
 •Consult the dealer or an experienced radio/TV technician for help.
Important:  Changes or modifications to this product not authorized by Apple could void the 
electromagnetic compatibility (EMC) and wireless compliance and negate your authority to 
operate the product. 
This product has demonstrated compliance under conditions that included the use of 
compliant peripheral devices and shielded cables (including Ethernet network cables) between 
system components. It is important that you use compliant peripheral devices and shielded 
cables between system components to reduce the possibility of causing interference to radios, 
television sets, and other electronic devices.
If necessary, contact Apple or take your iMac to an Apple-authorized repair center, such as an 
Apple Authorized Service Provider. Or consult an experienced radio/television technician for 
additional suggestions.
Responsible party (contact for FCC matters only):
Apple Inc. Corporate Compliance
1 Infinite Loop, MS 91-1EMC
Cupertino, CA 95014
Canadian regulatory compliance
This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject 
to the following two conditions: (1) this device may not cause interference, and (2) this device 
must accept any interference, including interference that may cause undesired operation of 
the device.
Operation in the band 5150–5250 MHz is only for indoor use to reduce the potential for harmful 
interference to co-channel mobile satellite systems. 
Users are advised that high-power radars are allocated as primary users (that is, priority users)   
of the bands 5250–5350 MHz and 5650–5850 MHz and these radars could cause interference 
and/or damage to LE-LAN devices.
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