Most likely: Crushed corner or edge on the CPU die from rough heatsink installation/removal. The dies were/are pretty fragile in that regard. If you notice chipping on the corners/edges there isnt anything you can do but make them into keychains or wall art... (some/many with chipped corners will still work though, but since yours dont work now its not likely the following will help at all.)

Make sure all the pins are straight (and present) it is possible to have a bent pin fold over and still insert the CPU (I have seen it in person, though they usually break off)

Also clean out with a small brush and some isopropyl alcohol or the like the bridges on the top surface of the CPUs (the places with the L# markings next to them, its possible for gunk to get in them and short them out.) Let them dry thoroughly after doing this, and be gentle.)

Use google image search or such, search for the CPU model and try to find a higher res image and compare to the ones you have, make sure the support capacitors are there and that the bridges that should be cut are cut. (people used to mod them.)

Even with no chipped corners, Athlon chips with exposed dies... die almost instantly if you pop them on with no or poorly installed heatsink. I've managed to destroy a couple CPUs this way, so be careful both when you're installing them and when buying one online, always ask if they've been tested.

die almost instantly if you pop them on with no or poorly installed heatsink.

Contrary to the popular belief, spread by the infamous THG test, you can't kill Athlon XP on a relatively modern board. CPU will shutdown immediately.

LoL, that is a 2007 video alright.

I must have used a KT133A based board (or was it KT266A based?) and I know for a fact that I killed a couple of CPUs on that board by powering it on with a dinky Socket 370 Celeron cooler that was not attached properly. Can't recall if I saw smoke, but the smell was pretty bad and CPUs never posted again 🙁.

Happened to me, too. Killed a Duron within seconds.

Normally, you can see such damage by the discoloring of the die.

I've also got a pile of Socket 462 CPUs that I think are dead. I need to try them in a different working board to make sure though.

If they came from a random lot of computer parts then I would not expect them to be working, especially if they were not packaged properly to prevent damage.

The few I have bought that were singles and packaged properly have been good.

These CPUs were pretty fragile when new. I killed a few of them myself back in the day.

Sometimes if you didn't get the heatsink on there just right (perfectly flat) before attaching the cooler bracket, a corner would chip. Sometimes it would kill the CPU and sometimes the CPU would still work.

I killed an athlon of some kind back in the day from overheating when I had a water cooling system that ran dry. (from evaporation not leakage) Think it was an Athlon 64

Oh yeah.. forgot to mention. The copper spacers that used to be sold for these CPUs is a lifesaver... literally.

But you have to watch out because there were different versions for different CPUs. The bridges changed places so the spacers can short out the bridges if the cutout is not correct.

The one I am using now I modified so it will work with all of them.

Copper spacers are not required. Just use strips of paper around the core or thin silicon pads. Never had any problems with proper coolers though, i.e. not typical GlacialTech and Thermaltake garbage.

The Serpent Rider wrote on 2020-01-14, 22:50:

Copper spacers are not required. Just use strips of paper around the core or thin silicon pads. Never had any problems with proper coolers though, i.e. not typical GlacialTech and Thermaltake garbage.

Of course they are not required.. but they can prevent you from damaging the core.

but they can prevent you from damaging the core.

Silicon pads are better.

Never got a bad cpu in my life. Killed a few though...p3s don't like poorly seated heatsinks at all.

kolderman wrote on 2020-01-15, 00:10:

Never got a bad cpu in my life. Killed a few though...p3s don't like poorly seated heatsinks at all.

🤣 same here ! Back in the day killed a few good P3 socket 370 cpu and a one Athlon XP cpu due to poor seated HS. Never would have happened if both Intel and AMD lidded the buggers back then.

i ruined a perfectly good Athlon XP 2600+ due to a poorly seated heatsink before. RIP Athlon XP 2600+ (2003-2019)
i was replacing the old paste with new stuff and i wasn't knowing what i was doing and i screwed up the CPU when attempting to re-seat the heatsink.

I should mention that all of them had some bent pins - actually quite a lot of bent pins - and I used very little force to straight them up - now I can put all of them in the socket with no force whatsoever. By now I think I am going for a refund because I can not make them work at all! All of my old ones are working but not these.

The only cpus I bought and proved non working were socket a, from an ebay guy that claimed to have a positive feedback before I could even try them... go for refund!