iMac G3 (Slot-Loading) Case Crack

[Concorde1993]

Yesterday, I purchased a 2001 iMac G3 for $20 on Craigslist. It came with the original manuals (still in the shrink-wrap), pro keyboard/mouse, and pre-installed with OS 10.2.8.

Overall, the computer is in excellent cosmetic condition (despite its age), however, it does have significant screen-burn (I have intentions of replacing that with a CRT from a faulty Bondi-blue; they are so easy to find in elementary schools), and a crack on the inside of the case (not the exterior) on the top right-hand corner.

I was hoping to post some pictures, however my Cybershot does not have an SD card (it uses some micro memory stick crap), and I have no access to a micro-USB cable at the moment.

If you own an iMac of this vintage, you probably know what I am referring to.

 

[Concorde1993]

Here are the pictures. I would have posted them sooner, but I was unfortunately caught up in Thanksgiving festivities.

Basically, my question is: how would one go about repairing this? What parts are involved? What do I need to remove (besides the cover, discharging the CRT, etc.)? Is it worth repairing, or should I just leave it alone?

 

[waynestewart]

Probably the best thing to do is download the service manual, look over the removal procedure and see if you feel it's worth the trouble

http://home.earthlink.net/~strahm_s/manuals.html

 

[mac2geezer]

You should be aware that disassembling G3 iMacs very often leads to further cracks and breakage. The plastic tends to be very brittle.

 

[Concorde1993]

Mac2geezer- I agree that the plastic on the original iMac series is not durable at all. However, if Apple had made the plastic any thicker, the convection system probably would not have worked (revenge of the 3 original Macs; goddamn you Steve Jobs!). Even with the materials used, my G3 heats up pretty quickly, sometimes to the point where the carrying handle becomes unbearable to touch (and I have adequate ventilation in my room).

Do you have any case cracks on your G3? The reason why I am posting this on the forum is because the housing on the top case on the right-hand side of the iMac (its right, not mine) has sunk a bit, in comparison to the left-hand side, which does not have this crack. Again, my question is: should I be concerned about this, or should I just leave this be?

 

[Gorgonops]

Again, my question is: should I be concerned about this, or should I just leave this be?

I think the answer comes in two parts:

A: If you're going to lug the machine around a lot then yes, you might need to be concerned. If it's just going to sit on your desk, probably not that much, and

B: If you take it apart to try to "fix it" (which I guess would mean either finding a non-broken iMac and stealing the correct parts, or slathering glue/epoxy all over it to reinforce it, which would look terrible) you may damage it a lot worse. (No problem if you have enough glue, I guess?)

I would swear the plastics on my B&W G3 are crumbling to bits despite the fact I haven't significantly moved or even hardly turned on the machine in three years. If you really want your example to last I might suggest a temperature-controlled and shock-mounted chamber filled with the noble gas of your choice. Anything less than that probably won't arrest the inevitable decay.

 

[Concorde1993]

Really, the plastic is crumbling? If you could post some pics to show an example, that would be most appreciated.

I have only owned this G3 for a week, and by far it has been a pleasure to use. When I was in elementary school, we had the Bondi Blue iMacs, and I instantly fell in love with them (although the Performas/Ppwer Macs that were replaced by them were better built).

I do not intend on moving this beast around (the only lugging I did was carrying it home from the facility I purchased it from in my hometown).

I was thinking of attempting to replace this part with a non-working iMac at my high school (I know quite a few IT guys that work for the board, so getting parts should not be too much of a hassle). I would like to keep this iMac for quite a while, so anything I can do to save it from death would be beneficial. I've got carpenter's glue, but I doubt that will work.

 

[Gorgonops]

Really, the plastic is crumbling? If you could post some pics to show an example, that would be most appreciated.

Perhaps "crumbling" is the wrong word, but my G3 has stress cracks emanating out from every one of the metal fasteners that hold the handles on (I actually won't carry it by the handles anymore lest one crack right off) and I also remember a pretty good hairline crack near the Apple logo on one side. (It's a huge pain for me to drag the thing out of the computer desk its hidden inside so I didn't feel up to verifying it.) I know that broken-off handles are a fairly common consequence of shipping the old towers, but mine was never shipped by mail (I got it from the original owner) and while it may of had a few tiny cracks when I got it I *know* they've been spreading without me manhandling it.

It's ironic that I recall Apple making a big deal about how their clear plastic cases were made of "tough polycarbonate plastic". While I'll grant the plastic is "harder" than the opaque plastic used in most normal computer cases it is definitely more brittle (almost like glass) so if it takes a hard enough impact it cracks instead of denting. My personal theory about spreading cracks in things like handles is that the complex curvy shapes Apple casts this brittle substance in by design build some tension into the resulting case parts, which means if the part doesn't fit *perfectly* or a minor impact deforms a mating part of the chassis then any crack once started will tend to propagate on its own. A more exotic theory I have is that it's *possible* some chemical, thermal, or photodegradation process is *naturally* forming tiny cracks in the material, which then propagate due to the built-in stress inherent in the curvy parts.

Anyway. Your photos are not really clear enough for me to see what's going on. If you think the iMac took a good smack that caused the original crack, *and* you can see that there are two parts that are clearly out of register, *and* you think that disassembling the machine and reassembling it "properly" would relieve some stress, then it might be worth doing. Otherwise... I'd put the blinders on and ignore it.

 

[Concorde1993]

Gorgonops-

Unfortunately my Cybershot, and the material used on the iMac, will not allow me to take a decent picture of the crack. When I use the flash, it reflects back (as seen in the shots I took), and when I do not use the flash, the picture is either grainy, or slightly out of focus. I do own more decent cameras (a Nikon FM2 & a Minolta XR5), but they are manual SLR, and it would be pointless to waste film on a shot I might not even be able to obtain correctly on 35mm, then scan it onto my MBP, which will only degrade the image further. I will attempt to reconfigure my Cybershot in order to demonstrate this problem when I have time.

When I first looked at this iMac, I noticed the severe screen-burn, which deeply pissed me off, as the original owner did not advise me ahead of time when I e-mailed him. The last thing I wanted to do was waste a bus trip, and make an ass of out myself, so I bought it for $20 (which was my original offer), and off I went. I noticed the crack on the side (its not on the graphite-coloured plastic; its on a white strip, which I assume holds the top housing of the iMac together) when I placed the computer on my sofa, then later on my desk. The only benefit was he had the original manual still in its original shrink-wrap (which must have some value), and the optional case cover to connect the iMac to an external projector, or monitor via VGA (and that was still in its shrink-wrap as well), in addition to an excellent looking, and working pro keyboard & mouse.

I would assume that the severe heat from the CRT, after years of use, caused this slight fracture in the case. There is no other physical damage to the case, besides some minor chips (ticks I call them) at the bottom, which I intend on filling, and if it had been dropped, the CRT may have shattered. The design does not look stable enough to tolerate a shock if dropped, and live to tell-the-tale, if you know what I mean.

 

[Charlieman]

When I use the flash, it reflects back (as seen in the shots I took), and when I do not use the flash, the picture is either grainy, or slightly out of focus.

Back lighting will fix that. A simple desk lamp with a conventional 40W or 60W bulb should suffice.

(I am guilty of taking many lousy photos of computer equipment too.)

 

[Gorgonops]

I would assume that the severe heat from the CRT, after years of use, caused this slight fracture in the case. There is no other physical damage to the case, besides some minor chips (ticks I call them) at the bottom, which I intend on filling, and if it had been dropped, the CRT may have shattered. The design does not look stable enough to tolerate a shock if dropped, and live to tell-the-tale, if you know what I mean.

Now that I know what I'm looking at... yes, I think that probably is a thermally-related crack caused by differential expansion of the front bezel and the clear bucket. I would swear I've seen similar cracks on the inside of other iMacs... and those 17" CRT Studio Displays Apple used to sell that had similar cases. That being the case I wouldn't bother trying to fix it. It would take some pretty serious disassembly to replace the part, and as for gluing it would undoubtedly just open up again, since by now the plastic has probably shrunk a bit. (You could try filling it with a color-matching epoxy without trying to squeeze the crack shut, but it might just open up a new crack somewhere else as time goes on.). It probably won't fail "catastrophically" if you just leave it alone. Worst case it might spread until it reaches the front of the bezel and becomes visible from the front, at which point the case might exhibit some signs of compromised structural integrity. My guess is it will stop before it gets to any joints, however.

To be brutally honest... don't expect your iMac G3 to last forever. All CRT iMacs have a problem with the monitor failing eventually because of a combination of brutal thermal conditions and so-so parts quality. (The original tray-loaders have a fan, yet they fail at least as often as the fanless slot-load units.) These units were simply not designed to last.

 

[Concorde1993]

To be brutally honest... don't expect your iMac G3 to last forever. All CRT iMacs have a problem with the monitor failing eventually because of a combination of brutal thermal conditions and so-so parts quality. (The original tray-loaders have a fan, yet they fail at least as often as the fanless slot-load units.) These units were simply not designed to last.

That would probably explain why they were low-cost when they were originally sold on the market ($899 for the base model, or something like that). That is quite unfortunate, as the original iMacs were absolutely gorgeous (hence why I bought this one).

The one I have was made in Mexico. Were all the first-gen iMacs made there, or were they made in Fremont (which is where the Macs should still be manufactured; not goddamn China)? :'( Would this have any significance?

Charlieman- take a look at the pictures of the SC20 drive on the compact Mac forum. I wouldn't consider those lousy. :beige:

 

[Concorde1993]

Gorgonops-

There are cracks on the left side. The one on the right has expanded as well. This definitely must be a thermal heating problem.

Oh well.

 

[Bunsen]

First of all, make sure the foot that runs the width of the front base of the iMac is popped forward. This lifts the base clear of the desk and allows more cool air to enter. Second, I would suggest propping up the rear an inch or so with a small block of wood or suchlike to get even more clearance. This will also raise the top vent relative to the rest of the case, which ought to improve airflow some.

You should be aware that disassembling G3 iMacs very often leads to further cracks and breakage. The plastic tends to be very brittle.

The slot-loading iMacs have an internal plastic frame which is far more fragile and susceptible to falling apart than the external polycarbonate shell. It's a different plastic, and much thinner. Alas, from my memory of taking them apart a/ that's the part that everything else clips to and b/ once you've taken the iMac apart, that internal plastic is as likely as not to crumble to dust in your hands.

I noticed the crack on the side (its not on the graphite-coloured plastic; its on a white strip, which I assume holds the top housing of the iMac together)

Yes, that's the stuff :-/

The one I have was made in Mexico. / Would this have any significance?

None at all AFAIK. The plastics would have been specified by Apple, and IIRC the ones we get here (Australia) were made in Thaliand. They suffer from the same plastic degradation. Your best bet is to ensure that it has sufficient ventilation underneath as described above.

 

[Concorde1993]

Bunsen- I have the iMac raised using the plastic strip at the bottom of the case. I also have an office cooling fan in my room, in addition to a return to allow air to come in (plus a window, etc., but it's too damn cold to keep it open now).

The iMac does not overheat per se (like a Plus without a cooling fan); it just develops these cracks. My concern is that if these cracks continue to expand, the top housing may collapse, destroying not only the CRT, and the entire case, but creating a big mess.

I should note that I do keep the iMac on sleep mode when I am not using it, as I do not want to wear out the power supply. There is still some heat being generated when it is in hibernation.

From what I have read, even outside of the 68k forums, this was a common cosmetic problem with the first-gen iMacs, and some of the Apple CRT studio monitors (or Design monitors, whatever they were called) with the translucent case.

 

[Bunsen]

I have the iMac raised using the plastic strip at the bottom of the case.

I'd still suggest raising the rear a little. Passive cooling needs all the help it can get.

The iMac does not overheat per se

They do have a nasty habit of blowing power supplies and other components which could well be heat (and age) related

 

[Concorde1993]

I'd still suggest raising the rear a little. Passive cooling needs all the help it can get.

I will consider doing that in the future. I just wanted to inform you that I did raise it a little, as I cannot use it when it is sitting completely flat on my desk (I doubt anyone can).

They do have a nasty habit of blowing power supplies and other components which could well be heat (and age) related

Actually, the power supply on this iMac has been behaving very well. As an owner of two Pluses, I doubt I will have to replace the PS on the G3 anytime soon, although the capacitors on the analogue board will probably be the first to go, as there is significant wear on the display (it was used in an office 24/7 after all). It is quite dusty, but I do have intentions of cleaning the innards probably during the Christmas break (and yes, I am well aware of CRT safety & procedures. I don't intend on dying young). :beige: