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This is really strange. For the last couple of vacations, the RAM in my home computer malfunctions when I come back.

I have a Dell OptiPlex GX620 as my home computer.

The four RAM slots have been populated as follows. DIMM DDR Synchronous 533 MHz 1 GiB in two slots, and DIMM DDR Synchronous 533 MHz 512 MiB in two slots. Total 3 GiB. Correctly paired.

The computer works fine, shuts down cleanly (Ubuntu 12.04 LTS), reboots fine during everyday use.

However, after the last three/four long vacations, when I turn on the computer, during the POST process, the computer beeps with the code (1-3-1) for memory problem.

In the very last case, I left the computer cleanly shut down, power cable plugged-in via a turned-on UPS on August 6. When I came back on August 15 and turned the computer on, it refused to turn on and beeped that scary beep (1-3-1). I turned off the computer by turning off the UPS (the computer power button did not work, even after long pressings) and then turned on the computer again, the same result every time. Only after I physically opened the computer casing, took out the memory modules and put them back, the computer turned on successfully.

I have run the extended diagnostics for RAM after the above scenario, no error was found.

I would appreciate any tips you can give me to avoid the above scenario. It is really a bother to spend couple of hours after every vacation, when you actually need to start work as soon as possible. I understand the scenario is somewhat difficult to recreate, but any advice will help.

Moreover, I would like to know why this happens after long shutdowns, why not after every day (mostly overnight) shutdowns. The prevailing conditions are the same for both the cases except the duration.

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Workaroud: no more vacations :) –  Hagen von Eitzen Aug 16 '13 at 9:44

2 Answers 2

up vote 2 down vote accepted
  1. Download memtest86, create either a bootable CD-ROM, or USB-Stick and boot from it.
  2. If the memtest turns out inconclusive (test results 100% OK for all modules), you may want to visually inspect all electrolytic capacitors on the mainboard and inside the PSU.
  3. If all of them seems to be OK, I'd suggest testing power rails with a multimeter while the system is booting up, if you don't want to do that, you can just swap the PSU temporarily, to rule out it's the PSU.
  4. If it's still inconclusive, it most probably some part on the mainboard, that is not showing signs of - well - dying visually. Usually, it's parts of the power supply circuity, supplying power to the RAM modules.
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I already have done memory testing using memtest86. This has been referred to as the extended diagnostics for RAM in my post. Edited to reflect the name. About other issues, could you please refer me to the relevant sites? I know that a simple search will return tons, but your pointers will be better, I believe. Any hint about the time issue? Why does the problem occur only after long vacations? Why not everyday? –  Masroor Aug 16 '13 at 11:34
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Issues with the voltage regulators and/or capacitors on the main-board can be time dependent. They build up electrical charge during use. This slowly dissipates when not used. Could very well be that the dissipation overnight/few days is not enough to trigger the issue while a 2 week holiday just might do the trick. Removing the RAM might just disturb the electrical circuits enough so it boots again. –  Tonny Aug 16 '13 at 12:19
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@Tonny Erm, well that's pretty much always the case, as this is how Caps work in the first place :) The ESR and capcaitance change when ElCos get old, that's why I've hinted at visually inspecting them. The problem with SMD ElCos is, that their venting port is usually on the underside, to the PCB. –  polemon Aug 16 '13 at 12:54
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@polemon I know that too. But most people have no idea... SMD elco's are a bitch. Usually not visually inspectable. And I have seen cases where it couldn't vent at all because they sprayed the entire PCB with a thin layer of black lacquer which sealed the tiny space between the SMD components and the PCB completely. Makes the PCB looks l33t for those overclockers with their see-through PC-cases, but those expensive motherboards where toast after 2-3 years. (Of course that is the typical customer base that would buy a new board every year so I guess that didn't matter too much.) –  Tonny Aug 16 '13 at 13:16
    
It was indeed the PSU. After that day, the computer was working, but it was sluggish during boot up. Also sporadic failures of HDD occurred. This morning, it failed to boot completely. HDD diagnostics showed failure (return code 7) of two HDDs out of three HDD. Found that these two get their power via the same cable. In the laboratory, putting the hard disks in another computer showed that they are indeed fine. Temporarily putting another PSU showed that the computer works fine as well. Then simply went to market, bought a clone PSU for around $12, and now my computer is good again. –  Masroor Aug 18 '13 at 8:37

The first thing I would look for in this case is dust or other contaminant buildup either inside the RAM slots, or on the contacts of the RAM sticks themselves. Take out the RAM sticks, clean out the slots, clean the sticks, check to make sure there is no oxide or anything like that on the contacts, and carefully reinstall them. Also check for any dust buildup inside the computer case. I would suggest doing this after the computer has been turned off for some time if possible, so as to simulate as post-vacation situation.

It is possible that contaminants could settle in a particular place in the slots with time (for example, at the bottom of the slots) in the absence of significant air movement, and subsequently the low voltage used for RAM may not be enough to overcome the electrical isolation caused by this. While the system is running or if it is turned off for only relatively short periods, e.g. dust may not have had time to accumulate in a single place because of the fans force-moving air around inside the case when the computer is turned on.

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I will check for contaminant inside the slots. But, I am still fuzzy about the time issue. If there are contaminants, why the problem occurs only after long vacations? Why not everyday? Or does a turned off computer enhances contaminant build-up? –  Masroor Aug 16 '13 at 11:31
    
@MMA See my edit. –  Michael Kjörling Aug 16 '13 at 11:44

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