iMac G3/600

[iMac600]

Well, get this. If I finish off my new PC, and hand the G4 over to my brother for him to use, I may be able to have my iMac back. Finally, the little guy may be my little "desk buddy".

However it's not going so well, the screen dims in and out, particularly when the system has been running for hours at a time. I've been told it's the PAV board failing, and it'll probably be gone in no time.

:'(

I'm not prepared to let it die though, so i'm willing to give it some "surgery". A spare PAV board in hand just in case it goes wrong, I want to try and add fans to this beast. At least one, hopefully a big 10cm fan to cover most of the ventilation system. I'm thinking mounted upward, facing toward the vent, so it not only pulls the warm air up but also blows the other warm air out of the vents.

Seems pretty straightforward, right?

The problem is rigging it up. I'll need to fabricate a plastic plate over the CRT and mount the fan up there. It really does sound like a difficult job but if I stick to it and put in all the effort I can, then it'll work out. The other option is to pull the fan assembly off a tray loading iMac, but i'm not willing to gut out a working tray loader.

Anyone done this before? Here's hoping we can save another old Mac.

 

[Danamania]

I popped a fan on top of my iMac g3/400 for 45C days - they have a thermal cutout that popped in from time to time, and it'd just turn off to protect itself from overheating. The fan solved it all - it's a 15cm ish one, and I made a cardboard shroud to tape onto the top of the mac. it sucks air out of the top of the iMac, and so pulls cool air in through the bottom.

http://www.danamania.com/tmp/imac_hat.jpg

Made such a difference!

(I put a layer of tape around the edge too, and taped more tape facing the sticky side too, so it'd seal a little better)

Dana

 

[iMac600]

Ah now that's a good idea, at least until I can have the internal plastics made up. If I may ask what is the fan connected to?

 

[Danamania]

Ah now that's a good idea, at least until I can have the internal plastics made up. If I may ask what is the fan connected to?

It's a 240V fan, so it's connected directly to the mains. Pumps masses and masses of air - but it's really a fan to be careful of - not like a 12V fan where you stick a finger in the wrong side and get a small ouch, this one bites flesh!

Straight from an 80186 server used by Adelaide City Council in the '80s.

Dana

 

[iMac600]

Ah, I see. Well I doubt i'll be able to source one of those so a 12v fan it is, now to just rig it up somehow.

 

[equill]

A 12-VDC supply is to be preferred instead of a rotating magnetic field near the CRT, as many a step-down transformer or AC adapter near the rear of my iMacs has demonstrated to me. Much preferable to a nearby fan of any voltage, however, is a duct above the iMac's outlet running at least a few feet to a box containing the fan and remote from the Mac.

That said, I have had the rear feet of my CRT iMacs (five of them) elevated at least 18mm (a handy commercial size of timber) in addition to the lift of the hinged front foot, and in one case 40mm (to make the display face vertical in a sound-editing rack), for some years. Always-on Summer 2000 iMacs are still going strong with the freer passive ventilation.

de

 

[iMac600]

I have noticed that elevating the rear of the machine has stopped the flickering screen, an indication that it's running cooler and therefore, running better. It's been running like this for about 3 days now.

EDIT: I jinxed it. Looks like even if I cool it down, it may need a new PAV.