Cleaning & updating a tray-loading
iMac (adding RAM, removing the hard disk, discovering the
internal battery, cleaning the fans, ...)
As usual, I cannot be responsible for any damage to
your machines when you will experiment the following
An tray-loading iMac will be dissambeld for a spring
In particular, we will focus our attention the (now) very
noisy fan and doing this, we will see how to add RAM, change
the hard disk and the internal battery.
First we put the iMac screen down on a soft textile.
The machine cannot slide!
Under the handle (blue arrow), a screw (yellow arrow):
The screw now out, the upper part of the iMac's case can
be slightly removed by pulling it to the top.
Here, the vacuum cleaner can already be used to remove
Now, we will operate the block made by the mother board
and the drives. First step, removing the connectors:
1) remove the screw pointed by the white arrow
2) unplug the cables on the right from their support
3) the connector showed under the black arrow is easy
4) ... but the screen connector (old Apple DB15
proprietary format) is screwed down (yellow arrows).
Also unplug the black connectors.
While keeping the cables out of the way, just slide the
mother block to the top.
The same block..now removed.
Note the fan's footprint dirty circle (the fan is still
in the last, not dissambled, part of the iMac)
On the right, the CD drive (fixed by two screws).
Remove the case above the CPU unit. We can see:
1) a RAM board (yellow arrow): big sized PC66
SO-DIMM 144 pins format. The sticker indicates a
A-revision machine: so max of 256 MB RAM (B-revision
2) the battery (blue arrow)
3) the white arrow on the top points to graphic chip,
the white under points to the slot for an extra VRAM
4) The black arrow indicates the screw to be removed.
5) And just above this black arrow, the PMU reset
We remove the cooling unit clamping spring and remove the
Now the board on which are fixed the processor and the
RAM supports can be extracted.
This board is, on the left, locked onto two special
connectors (yellow arrows) and, on the right, simply engaged
inside the metallic case (blue arrow).
In this very, very critical part of the iMac... do not force
on any parts: if the part cannot be constraintless unplugged
frow a connector, this surely because you pull it in a wrong
The metallic case is to be vacuum cleaned, other pieces
can simply be puffed.
Surprisingly, no thermal paste onto the CPU unit!
The board's reverse face. On the right:
* the two excrescences which has to be engaged
within the metallic case
* the support for the extra RAM: small sized this one!
Now looking for the hard disk.
Remove the fixating screws (yellow arrows)...
... and remove the IDE cable (blue arrow).
The CD drive is now freed: in fact, except for the two
screws which has to be removed, the drive is simply locked
by a spring.
So the drive has to be gently pushed towards its back...
towards the motherboard in fact... to be removed.
So, the last piece we discover on the picture is the hard
disk. The last, but certainly not the least, operation to
The simplest way to remove it: to remove first the
-> so, we remove the last three apparent screws on the
... and the one pointed by the yellow arrow.
We can now safely disconnect the mother board from its
Caution: many connectors and cables to be slightly
The hard disk can now be operated.
On the picture, the power cable is above and the IDE
cable (also used for the CD drive) below.
The IDE cable passes inside a ferrite ring: this ring
acts a a Faraday's cage to prevent the electro-magnetic
field generated by the IDE cable (yes, small electrical
values...but non zero values!) to intefere with the mother
board circuits (placed just above the hard disk).
The two screws pointed by the yellow arrows have to be
removed and the ones on the rear side also!
One can put a bigger hard disk, but the hard drive
controller only allows a maximum capacity of 128 Gigabytes.
The hard drive back in place.
What a wonderfull imbroglio of cables... amazingly
constrasting with the Apple's design of the machine ;-)
To put back in place the CD Drive, one has to put the
spurs into their nicks (yellow arrows) and clamped the
craddle in the spring (blue arrow).
Push the spring towards the rear part of the drive and
let it to slightly relax: the spurs muts appear on the
locations pointed by the yellow arrows.
Blue arrows show the two digged up area which help to
position the block into the iMac's chassis.
So, as far as this chassis concerned...
As we just remove the block containing the motherboard,
it is the right moment to pay attention to the CPU's fan.
The runny times... and the dust... help it to break the
legendary noiseless way of working of the iMac ;-)
So a deep cleaning is required: vacuum cleaner and
paintbrushes on the deck!
We can extract the screws (yellow arrows) and remove the
fan's craddle from the cockle.
... and again four screws!
Clean it. Remove the sticker and spray a little bit of
sewing machine oil on the fan's axis. Place the sticker
As usual, follow the instructions in a reverse order to
rebuilt the machine ;-)
Take care, when sliding the mother board block into
place, that the two digged up areas in the chassis exactly
match the plastic spurs (yellow arrows).
Do not forget to put all the cables back in place,
exactly where and how they were before removing them: every
single place is reckonned on an compact iMac!
... on both sides of course ;-)
If you wish to thank or forsten me...