Apple mac pro 8x User Manual

							Mac Pro (8x) Take Apart — Processor Heatsinks 71
Using a long-handled, magnetized 3 mm flathead hex screwdriver, loosen the four captive 2. 
mounting screws for the upper processor heatsink in the order indicated below. 
Lift the heatsink straight up and out of the enclosure.3. 
Disconnect the cable connector for the lower processor (CPU B) heatsink. 4.  
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 72
Using a long-handled, magnetized 3 mm flathead hex screwdriver, loosen the four captive 5. 
mounting screws for the lower processor heatsink in the order indicated below. 
6. Carefully tilt the heatsink so that it clears the bottom lip of the enclosure and then lift the 
heatsink out of the computer.
IMPORTANT:
Remember that you 
cannot leave the 
heatsink separated 
from either the upper 
or lower processor for 
more than 30 minutes. 
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 73
Visual Inspection of Heatsink Gasket
Before installing a new or existing heatsink, check that the gasket that surrounds the silver-
colored coating on the underside of the heatsink is in good condition, as illustrated below.
Replace the gasket if it shows obvious damage, such as cracks, folds, and broken-off surfaces, or 
if it is dislocated from the heatsink. The gasket is available through GSX as part of the Mac Pro 
Grease Kit, part number 076-1258. 
Replacement Instructions for Krytox Grease
The Mac Pro (8x) uses Krytox grease to ensure a proper seal between the heatsink and processor. 
A bead of the grease rims the gasket on the underside of the heatsink and comes pre-applied on 
replacement heatsinks. 
Re-installing Existing Heatsinks/Processors
If you are re-installing existing heatsinks and processors, or transferring existing heatsinks and 
processors to a replacement logic board, in most cases you do not need to reapply Krytox grease.  
However, if additional grease must be added, do the following:
Order the Mac Pro (8x) Grease Kit (part number 076-1258).• 
Reassemble the unit while you wait for the kit to arrive.• 
Once you have the kit, remove the heatsink and/or processor from the enclosure.• 
Using first the lint-free cloth and then the alcohol wipe from the grease kit, carefully clean • 
off any residual grease from the underside of the heatsink and the top of the processor. (See 
“Installing New Heatsinks” below for more information.) Finish wiping the surfaces one 
more time with the cloth. 
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 74
Using the pre-measured syringe of Krytox grease from the kit, evenly apply a bead of grease • 
around the full perimeter of the heatsink gasket. Apply the full syringe of grease to the 
gasket. 
Warning: Do not apply more grease than recommended. The grease must not overflow the 
heatsink and come in contact with the processor connector.
Do not apply any grease to the processor.• 
Installing New Processors
Do not apply new grease to either the heatsink or the processor. 
Installing New Heatsinks
If you are installing a new heatsink, do not apply new grease to either the heatsink or processor, 
as the replacement heatsink comes with the full capacity of grease applied. 
Note: When installing a new heatsink, be sure to remove any residual grease from the top edges 
of the heatsink’s processor. To clean off the grease, do the following:
Remove the processor from its holder on the logic board. (See “• Processors” in this chapter.)
Using first the lint-free cloth and then the alcohol wipe included with the replacement • 
heatsink, carefully clean off any grease from the top edges of the processor. Be very careful 
not to touch the silver-colored coating on the top of the processor and the gold pins on the 
bottom of the processor.
Use the cloth to carefully wipe the top edges of the processor one more time to clean off any • 
remaining grease. 
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 75
Replacement Instructions for Heatsink
Note: If you are re-installing an existing heatsink, go directly to step 1 below. If you are installing 
a replacement heatsink, first do the following:
Unpack the new heatsink according to the instructions included in the parts box.• 
• Remove the protective cap covering the underside of the heatsink and transfer it to the 
heatsink you are returning to Apple. 
Apply the top gasket included in the parts box to the top of the heatsink.• 
IMPORTANT:
If you are installing a 
new heatsink, do not 
remove it from its  
vacuum-packed bag 
until you are ready to  
install it. Be sure to  
follow all directions for 
unpacking the heatsink 
that are included in its 
packing box. 
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 76
If you are replacing the lower processor heatsink with a new heatsink, install the bumper • 
included in the parts box on the side of the heatsink.
Visually inspect the gasket on the underside of the heatsink. See “1. Visual Inspection of 
Heatsink Gasket” earlier in this procedure. 
Carefully align the posts on the lower heatsink with the mounting holes in the logic board, 2.  
and lower the heatsink onto the processor.
Lightly tighten the heatsink mounting screws in the order indicated below. 3. 
To secure the heatsink to the processor, again tighten the screws in the order indicated.4. 
Repeat steps 1–4 for the upper processor heatsink.5.  
						

							Mac Pro (8x) Take Apart — Processor Heatsinks 77
Disposal Instructions
Place all disposable materials used in removing or replacing a processor heatsink or processor 
inside the resealable plastic bag included with the replacement module. (Disposable materials 
include such items as protective gloves, alcohol wipes, lint-free cleaning cloths, Krytox grease and 
syringe, suction pipette, and heatsink gasket.) Pack this bag along with the failed module in the 
box that the replacement module came in, and return the box to Apple. 
						

							Mac Pro (8x) Take Apart — Processors 78
Processors
The Mac Pro (8x) computer uses a special coating on the processor heatsink and processor to 
manage the temperature in the computer. The silver-colored coating comes applied to the 
underside of the heatsink and the top of the processor.
Use the following guidelines when handling the processor heatsink and/or processor:
• Wear disposable nitrile or latex gloves.
Avoid touching the silver-colored coating on the underside of the heatsink and the top of • 
the processor.
Always make a visual inspection of new or existing heatsinks and processors before • 
installing them in the computer. See “Processor Heatsink and Processor Visual Inspection 
Instructions” in the Troubleshooting chapter for more information.
When removing or replacing the heatsink and/or processor, do not allow the heatsink to be • 
separated from the processor for more than 30 minutes. The special coating on the heatsink 
and processor degrades with exposure to air; more than 30 minutes exposure could result in 
damage to the computer and a repeat, multi-part repair.
Identifying Version 1 and Version 2 Processors
There are two versions of the processor, Version 1 and Version 2, which must be replaced like-for-
like. In addition, both processors in a dual configuration must be the same version, either 
Version 1 or Version 2. Different versions in the same computer could cause a system failure.
Note: You may still replace a single processor, but you must replace it like for like. There is no 
performance advantage to either version of the processor.
To identify the correct processor for the computer you are repairing, please check its 
configuration code (the last three alphanumeric characters in the serial number for the 
computer). The following table lists the configuration codes that use Version 2 processors; all 
other configuration codes use Version 1 processors. If you do not have the correct processor, 
please order it from GSX.
Configuration CodeVersion 2 Processor
0LN, 0LS, 0LT, 0LU, 
08S, 0GP
3.0 GHz  (661-4611)
IMPORTANT:
If you need to install 
a new heatsink or 
processor, reassemble 
the unit while you are 
waiting for the new 
part to arrive. 
						

							Mac Pro (8x) Take Apart — Processors 79
Tools
No tools are required for this procedure. However, you may find a flat-blade screwdriver helpful in 
releasing the processor holder latch.
Preliminary Steps
Before you begin, open the computer, lay it on its side with the access side facing up, and remove 
the following:
Hard drives and hard drive carriers in drive bays 1 and • 2
PCI Express card installed in slot • 1
Any 12-inch PCI Express card• s
Processor heatsink cove• r
Front fan assembl• y
Top and bottom memory card• s with DIMMs
Memory cage with rear fa• n
Processor heatsink• s
Part Location 
						

							Mac Pro (8x) Take Apart — Processors 80
Procedure
Note: This procedure illustrates how to remove the lower processor (CPU B). The instructions are 
the same for removing the upper processor (CPU A). You may, however, want to use a flat-blade 
screwdriver to release the latch on the upper processor.
Release the latch on the metal processor holder. 1. 
Note: You may want to use a flat-blade screwdriver to release the latch on the upper 
processor. 
Rotate the top of the holder to the open position. 2.