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**Paul** · October 14th 12, 12:13 PM posted to alt.comp.hardware.pc-homebuilt

wrote:
I bought some used DDR2 DIMMs to match a pair what I had already. I inserted them into my good PC and it would not boot - no display, not even a beep error code.
So I removed the suspect DIMMs, and still my PC does nothing. Only after replacing the original DIMMs with a third pair did the PC boot.
Next I put the suspect DIMMs in a spare computer, and it gave beep code for
memory failure (has a different mainboard to the other PC). Also tried the original DIMMs that were good, and found they also give bad beeps. So it appears that I got some bad memory which furthermore damaged the original RAM in the nearby slots. I contacted the seller who swears on a Judeo-Christian storybook that they were A-OK when he posted them. They were wrapped in an anti-static bag.
I have been building and upgrading PCs for over 15 years, and have never zapped any modules. And both PCs were set at standard frequency and voltages.

You can have DIMMs that are so defective, they burn the motherboard.
That's the worst kind of failure. (A DIMM capacitor failing short, on a
motherboard without OC protection, can do that.)

All it takes, is for one DIMM to jump on the bus while the
other DIMM is trying to do that, to cause problems.

So yes, there are a few failure modes that can have a widespread
impact. And, as you note, the testing procedure after an
event happens, can result in multiple other pieces of kit
getting toasted. For example, when you inserted the third
set of DIMMs, and got the "all clear" indication from your
motherboard, if the motherboard was damaged, you could have
had the third set toasted as well. That's if the DIMMs
damaged the motherboard in such a way, as to cause the
motherboard to damage subsequently installed DIMMs. There
have been some pretty expensive "domino effect" failures
people have run into. Usually, people figure it out, after
they've toasted a third set of something :-(

Paul