Does it mean that no chip could be fabricated from October to December?

Puppy wouldn't be my first choice, honestly. If it's running, then you have a VERY workable and usable platform. As said, I had the latest Tumbleweed running very nicely on a 21" Core2 Duo iMac, with no problems at all. The Apple store *WILL* tell you that, because they want you to fork over $$$ for a new machine, for no good reason, and there have been countless articles/videos you can find of Apple telling customers just that.

Again, you either have a bad USB port, drive, or didn't burn the image correctly. The fixes are simple:

• Burn the image again
• Try a different USB stick
• Try a different USB port

If you have another system, plug the USB stick in it, and see if it will boot. If not, you've narrowed the problem down. Since the iMac *DOES* function, it is VERY likely that you haven't burned the image to USB correctly. I would *STRONGLY* suggest you use openSUSE Tumbleweed, Ubuntu, or Fedora instead of Puppy. The amount of hardware supported out of the box is greater.

Be aware that opening your iMac isn't hard. You *CAN* change the wifi adapter out easily, and for about $20, can have the latest bluetooth and wifi in there. Apple may not support it, but Linux sure does. That's one piece of hardware that isn't apple-specific. Further, you can (and probably SHOULD) swap out the hard drive with an SSD. Runs much cooler and faster.

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It would seem so. They were usually used on 8 pin chips until SMT came along. Some pig-ignorant companies persisted. I haven't seen 3 digit date codes in a long time. Despite 30 years in the business, I never found out what they did with the last quarter.

OK good news and bad news. First the good news there must have been a problem with the usb drive the way it was written. But the good news is I solved the problem with a live dvd of Linux mint. Installed and runs great...To a point. That brings up the bad news. There must be a memory error or maybe a power supply problem. It runs linux great and fairly speedy. Much speedier than the MAC OS. But after maybe an hour the mac just freezes. Probably the reason the owner got rid of it to begin with. And the store I got it from only checks to ensure an item is working (ie it powers up and boots) so they would not have seen the problem. I will just chalk up to a learning experience on how to get a old Mac up and running Linux. But I am not going to put money into replacing memory or any other part on a Mac.

Thank you to everyone who responded to this thread.

I wouldn't write it off yet. First, get the glass off, then clean its innards. Likely it's never had more than a superficial cleaning and some component is overheating. A somewhat less likely possibility is there is a bad capacitor, identifiable by simple inspection, either leaking, and/or puffed at either or both ends.

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I agree with mrmazda, and ask about how the case feels before it shuts down. While I do like the form factor of an iMac, they can be flaky when it comes to internal design and some of their hardware decisions. One small vent gap at the top and some holes at the bottom can cause overheating, especially as mrmazda pointed out. From a thrift shop is different than a hardware refurbisher. Also, does the system have an SSD in it now?

Opening it is easy, but be careful. Get two suction cups, stick them on the glass towards one the top corners, and pull...glass is held on by magnets. Lay it face down, and be sure NOT to touch the back. Nothing bad will happen, but it's galactically annoying when you get the whole thing put back together, and find a fingerprint on the INSIDE of your screen. You will have to remove the monitor..again, not hard. It is a torx bit, and I *THINK* it's a T4 or T5, several running around the edges. Remove all, lift screen up from top CAREFULLY...there are microphone and other connectors you will have to disconnect. Lay screen aside, and behold the entire guts of your system. Take canned air to it, check the vents, and it would not be a bad time to put a drop of lubricant on each of the fan motors (carefully). De-dust the whole thing, check the connections.

If you're using an SSD, be aware that SOME models will assume that your system is overheating, due to the lack of a particular sensor that's missing from SSD's. Easy to fix:
https://eshop.macsales.com/item/OWC/DIDIMACHDD11/

If you're going to open this up, I'd strongly suggest you go ahead and pick up an SSD (if you don't have one), a new wifi card (since you don't NEED an Apple-blessed one any longer) that's faster, and the SSD sensor. Any Wifi card like this will work:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

...but you may need a half-height to full-height adapter (an additional $6). Before spending money, though, make sure it's a heat issue. I've got a 27" i7 model, and my case is barely warm, and internal sensors say it's running about 38c (100F). If your case is hot to the touch...I'd strongly suspect overheating. Running an SSD will also make it run cooler. All this aside, even IF you get a new SSD with a new Wifi card, you can still use those things in other systems...regular SATA drive and standard wifi...not like you'd be wasting money.

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