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iMac G3 Test Bench / Show case

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May 27, 2010
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Motherboard
Dell Optiplex 9030 All in One
CPU
i5-4690K
Graphics
HD 4600
Mac
  1. Mac mini
Classic Mac
  1. iMac
Mobile Phone
  1. iOS
This is my iMac G3 mod that owes some inspiration from this new Lian Li case:

hnys.jpg


The Lian Li is a Mini ITX case and also is a very boxy aluminium design, so apart from the concept of putting the motherboard on show inside a "TV" like housing the similarities end there.

The iMac was originally my wifes and served her for many years before the CRT went on the blink. It was too nice to throw away, too worthless to sell and the idea of putting a low res 14" monitor in it did not appeal and this combination of factors mean it has sat on top of my cupboards for some time since (probably 3 years or more).

The idea though of putting all my hardware center stage inside this box is appealing and it has room I believe for an mATX system to be mounted.

This first post is all about the teardown and checking the concept.

Here is how it looked before I came along and took it to pieces.

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I did not use a teardown guide, but I have documented the process here. First I turned the iMac over and removed the cover for the video output as well as the RAM access slot:

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Next, there are four screws accessible for taking off the bottom main plastic part.

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Once those are undone you can tip up the bottom part and remove it:

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There are two screws that need to be undone to remove the front trim part - and here you see the grey cover that needs to be removed to access one of them:

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and the other:

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Once these are undone the front will pull off.

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I chose to then work on removing the original motherboard, but first the faraday cage needs to be removed. Here are some shots of it as well as of the little iMac speakers:

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The faraday cage is held on by a few easily accessible screws and comes off simply enough.

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Underneath the cage we see the mobo:

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and the neat little combined HDD tray and DVD carrier.

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The mobo once disconnected comes off easily enough and you are left with a bottom plate exposed:

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This plate will not come off now though, so instead I turned to removing the speakers:

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They have three clips which attach - one central clip that has a prong that needs to be depressed form underneath, and two outside clips. Press the central prong in and then slide the speaker outwardly to remove.

Turning back to releasing the top plastic, undo these screws (which are hidden under two grey clips above the crt top):

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as well as a screw at the back of the shroud (not shown here sorry) which attaches the translucent "grape" coloured cover to two side plastic parts and then tilt and slide the cover downwards and it will come off.

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Look at the clips that are shown in the photo below and you will see why you need to slide the shroud downwardly to get it removed:

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After this you are left with a couple of plastic side pieces and a front plastic part that attach to the metal tray and which hold the CRT and the high voltage PCB tray.

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At this point disassembly is relatively straightforward in that if you find a screw you unscrew it. HOWEVER, at this stage do STOP. You have exposed the CRT and it now needs to be discharged. Failure to do that now and putting yourself in the wrong place can result in a very nasty electric shock that can potentially be fatal.

Watch this on what to do and precautions to take:

http://www.youtube.com/watch?v=bDAiLtTDuf4

You will also find on Google an enormous amount of warnings about death from CRT…….mostly written about by people who do not have much electronics knowledge. I did find this interesting too:

http://lowendmac.com/tech/crt_danger.html

In any event, I suggest you do follow all instructions for avoiding discharging the tube through your own body and please do it safely. Once safe you can carry on taking stuff apart. Usual note - please do not hold me responsible for any injury you might sustain. Be careful and everything will work out fine. Most important though do not simply go poking a screwdriver at the CRT before you understand the risks and what you are doing.

Having disassembled my iMac I put the parts together again without CRT and PCBS to make sure it all would re-attach perfectly and to make sure I had all the parts I needed.

Of note I kept the side IO piece which will be re-used and I also broke off the power inlet from the high voltage PCB to keep as it will screw attach to the metal support plate and can be easily and sturdily re-cycled for the build later.

Here are some pictures now of the basic parts re-assembled:

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and that is where I am right now.

Things to come:

Making a tray for the motherboard; making fan support (to utilise the area around the "handle" at the back); making a front "screen"; sorting out everything else!!!
 
So, first small steps.

I made a rough tray model - needs work! -to see how things might fit together and also have done what I hope will be the only cut to the case.

In the area behind the screen on the pointed back is a handle area which also vents the iMac. This has a reinforced area that bulges down into the main case.

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Decided this would be the logical place for a case fan and with the tray sitting at an angle a fan can very efficiently blow down onto the hardware and get a good back to front breeze going.

So I set to removing the bulge and it is not so easy.

First step remove the handle.

z2i6.jpg


Removing that is a matter of undoing 4 screws from the inside and it is then located by various downwardly protruding tabs. It is pretty much impossible to remove without breaking the top and bottom tab - the others just will then pull out.

As I didn't know how things would go I cracked out the dremel and started cutting a lot deeper down in the bowl of the bulge than I wanted to be.

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This turned out to be sensible as this plastic is much harder to cut than most metals - simply because a rotary tool will heat it up quickly, it then melts and clogs to try and seal the cut back up again.

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Eventually it cut out.

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As it does not cut neatly with any power tool, it is best to finish off with filing.

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and then eventually you can work your way up towards the ridge of the bulge. I think it best though not to go all the way up as this fold ridge will be a strength point and removing it will more than likely mean that the plastic will crack easily.

u3zw.jpg


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After a bit of sanding I then took a couple of shots with a fan (held in place with tie wraps for the photo) and a tray in place to show the concept and see what space is available.

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nwzr.jpg
 
Hi Minihack,

interesting project! Have You decided what to use instead of a screen yet? A laser-etched screen of acrylic sheet maybe?
I´ve given my Blue Dalmatian some thoughts too, but decided to leave it as it is right now, since it´s still running quite ok. It´s in my guest-room now and people always ask when Apple decided to make "cute" machines like that.
My next project will definitely be my eMac and i already decided to put a fan in the same spot as it is on Your G3 right now. As i plan on going without a CPU fan, i wonder if it will be enough to just draw the air out with this top fan? (Want to use a 120 or 140mm fan on low rpm and there´s some vent-holes on the bottom.) Or if i should put another one where the original "jet-fan" used to be?
Decisions, decisions...

Olli
 
Hi Minihack,

interesting project! Have You decided what to use instead of a screen yet? A laser-etched screen of acrylic sheet maybe?
I´ve given my Blue Dalmatian some thoughts too, but decided to leave it as it is right now, since it´s still running quite ok. It´s in my guest-room now and people always ask when Apple decided to make "cute" machines like that.
My next project will definitely be my eMac and i already decided to put a fan in the same spot as it is on Your G3 right now. As i plan on going without a CPU fan, i wonder if it will be enough to just draw the air out with this top fan? (Want to use a 120 or 140mm fan on low rpm and there´s some vent-holes on the bottom.) Or if i should put another one where the original "jet-fan" used to be?
Decisions, decisions...

Olli

Hi Olli,

Well, I am thinking of a bit of a twist to this now, wondering if I can make a mechanism that will allow me to simply swap fronts so that it can move quickly from completely open to having a high resolution laptop screen suspended there. Then it'd have a bit more interest......

As for running without a CPU fan it of course really depends on powerful a system and the heatsink. The iMac itself (no idea on the eMac but probably the same) is a case where there is pretty good ventilation and was originally made to run without a fan, so potentially a single fan may well be enough to expel heat in many situations.
 
Swapping out fronts, eh? Makes the tinkerers mind go round... Hmm, maybe a system that uses magnets, those could easily be hidden behind all that plastic on these cases, maybe in conjunction with one of those things that snaps open the glass-doors of showcases?
As for the big E; i wasn´t planing on going to big. Want to use my Q77M-D2H that i didn´t use in my G4 after all, an i3 (most likely an 3225) and a pico PSU. A SSD and i want to retain the DVD-capability, i.e. by a new drive.I love the old Pioneer that the mac has know, but i´m afraid it can´t be salvaged as PATA/SATA adapters don´t seem to work on opticals... I plan to go with the HD4000.
I´ve set my sights on a few options for CPU-coolers, but i will have to wait and see how much space will be left and how the mobo will fit inside...

Olli
 
I´ve set my sights on a few options for CPU-coolers, but i will have to wait and see how much space will be left and how the mobo will fit inside...

Olli

Well, if it is anything like the iMac there is a ton of room inside. That's what tempted me to use mATX - that and the fact that I had to rip my old gigabyte mATX board out of my MDD when I sold it, so it is available and I don't think anyone would buy that old board off me (it is my venerable GA-P55M-UD4 with an old style i7 1156 CPU). However, I must on reflection think about what would work best in there instead of what I have in my stock of parts and surely it is really an ITX board that is the sensible choice and would look the best inside the case. But then again that sort of shoots down the original idea that the system could be used as a test bench as a test bench limited to an ITX configuration isn't much use to anyone. Too much to think about.

Another thing is that I am now also re-thinking doing another MDD - as I did a part exchange on mine when I sold it - so when I am not sleeping at night my mind is whirring on that project too.
 
My next project will definitely be my eMac and i already decided to put a fan in the same spot as it is on Your G3 right now. As i plan on going without a CPU fan, i wonder if it will be enough to just draw the air out with this top fan? (Want to use a 120 or 140mm fan on low rpm and there´s some vent-holes on the bottom.) Or if i should put another one where the original "jet-fan" used to be?
Decisions, decisions...

Olli
Another possibility for consideration if thinking of going without a seperate CPU fan is to create a seal between the case fan and the CPU heatsink. Thus the case fan combines both roles, sucking air through the heatsink, and expelling it out of the case.

I have done this in my G4 cube build, and does the job. Construction can be in cardboard or thin plastic, so not hard to make.

Kiwi
 
Hi Kiwi,

I saw Your hose and i was to implement something like it in my G4, once i put another fan in the bottom of the case. I want it to channel fresh air directly onto the cpu-fan.
In the eMac this idea will get interesting, how does one make sure everything connects once you put the case back together... Maybe flexible tubing could be a solution?

Minihack: Wow, looking at my G3, i was almost sure an mATX board would not fit in there. If i were to remake it i´d go for itx too. By the way, You didn´t say (i think), will You put in a new slimline- DVD/BL drive?

Olli
 
Hi Kiwi, ...

In the eMac this idea will get interesting, how does one make sure everything connects once you put the case back together... Maybe flexible tubing could be a solution?

Olli
Based on the photo's that minihack has provided of the iMac I would mount the fan on top of the heatsink, but reverse the airflow, then securely attach the cardboard cowling to the fan, that acts as a chimney directing the air to the external vent. The outer case cover can but put in place, mating up with the cowling.

The cardboard can be trimmed through simple trial and error, it is flexible so a little deflection is OK, and of course a perfect seal isn't crucial. Sorry havent seen an eMac, assume may be similar
 
Hi Kiwi,

I saw Your hose and i was to implement something like it in my G4, once i put another fan in the bottom of the case. I want it to channel fresh air directly onto the cpu-fan.
In the eMac this idea will get interesting, how does one make sure everything connects once you put the case back together... Maybe flexible tubing could be a solution?

Minihack: Wow, looking at my G3, i was almost sure an mATX board would not fit in there. If i were to remake it i´d go for itx too. By the way, You didn´t say (i think), will You put in a new slimline- DVD/BL drive?

Olli

For sure the mATX fits absolutely fine (and can even be loaded in through the front of the iMac while already attached to the tray). I want all the cabling though to look neat and be easy to fix in place and an ITX - as it would have LOADS of space around it - would make a neat job extremely simple to do and it would look great too. So I'm still in two minds and may stick with an mATX just to give a bit more of a challenge. I'll give it a few more restless nights thinking about it before I decide (most of my ideas come when normal people would be sleeping...).

And for certain I will be putting in a slimline DVD drive. The conversion and mounting of that is exactly the same as with a Cube. By that I mean there is a really neat caddy and an over sized ancient slot loader so I'll rip out the guts of the old IDE slot loader and pop the slimline one inside it. There is also no need to worry about hard drive space as I can also re-use the original sled for that.

For PSU I am torn between three options: 1. I have a SFF Silverstone that will fit easily; 2. I have a BeQuiet proper ATX supply that I'd like to try and believe will go in okay with a bit of internal cutting; 3. I have an MDD power supply that this weekend I re-wired for ATX (see the couple of pic.s attached) - it is nice and thin and so would also fit naked "downstairs". A cool thing about the MDD supply is it also has an integrated 25v supply at 4.2Amps which would be great to run a studio display off......the not so cool thing about it is it has only 16Amps on the 12v line so I'd need to stick to integrated graphics or a low power GPU.
 

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