andaluz

Hi
I've been experiencing a few problems recently with my Dell Dimension 8400 running WinXP (Home edition - SP 2) . There have been intermittent Blue-screends and the occasional incident where the machine won't boot at all. I checked the diagnostic lights at the back of the machine and this indicated that there may be a problem with the memory modules.

My machine is configured with two 512Mb modules of DDR2 SDRAM. I worked my way through the instructions in he owner's manual for this problem which basically amounted to removing and re-siting the modules. The mahcine successfully rebooted but now reported that only 512M of RAM was installed. I've tried removing and replacing the modules sewveral times to ensurethat they are positioned correctly but the machine still 'thinks' there is only one 512 module in place.

The machine shipped with a Dell diagnostic tool which I ran in an effort to narrow down the specifics of the problem and it confirmed that as far as it was concerned only one module was installed. A summary of the config readings from the diagnostic tool are as follows:

Installed RAM: 512 MB
Mem speed: 400 mhz
Mem technology: DDR2 SDRAM
Mem channel mode: single

Channel A, DIMM 0 - not populated
Channel A, DIMM 1 - not populated
Channel B, DIMM 0 -
slot colour: white, size: 512 Mb, no of ranks: 2,
org: x8, cycle time: 5.00 ns, Access: 0.60 ns, ECC: no
Channel B, DIMM 1 - not populated

I would have expected Channel A, DIMM 0 to have been populated as well but I'm guessing!

So my question is : is there anything else I can do to narrow down this problem or is it now a question of buying new Dell memory modules?

Any help gratefully received.

thanks

wrench97

Looks like you have then in the second set of slots they should be in the first slot and the third slot I believe the slots are color coded for the matching pairs.

andaluz

I've just double-checked the slots after your post. They're both in the 'white' slots and they're numbered:

[1] - white
[3] - black
[2] - white
[4] - black

I'm assuming that each slot represents DIMM n

I've eyeballed the modules but there's nothing obviously broken/snapped (more out of desperation than sceintific analysis!)

wrench97

Try swapping them to the black slots. If that doesn't work d/l memtest and boot to the program testing 1 stick at a time to see if you get any errors.
http://www.memtest.org/

andaluz

Thanks wrench97. Will report back after a memtest run: is it advisable to run this overnight??

BTW, I swapped the modules across the white slots to no avail but would seem to indicate that the sticks themselves aren't the problem but possibly slot 1.

wrench97

That's why I suggested using the black slots first if the slot is bad then you'll unpredictable results in memtest.
If the stick is bad enough not to be seen in bios 10 minutes or less will do it.

andaluz

OK - will try that as well though I've just read the Dell docs again and they warn against putting the sticks in the black slots only. They don't say why.

Thanks again

wrench97

Some of the Dell boards will work that way some won't
What happens if you just put 1 stick in the 1st slot?

andaluz

Just tried one stick in slot 1 and tried to reboot. The machines starts beeping and doesn't reboot at all. The diagnostic lights at the back have A=orange which, according to the docs is "A possbile USB failure has occurred" which is puzzling. The only USB device connected at the time was the mouse. Eyeballing the m/board doesn't provide any extra clues, either.

Resiting the sticks in the black slots gives me 1G RAM which is fine but troubling as it now indicates that slot 1 is broken??

I will try both stick in the white slots again and run memtest to see what happens.

cheers

andaluz

Quick update to the above.

When booting with only one stick in slot 1, as soon as the power is turned on at the wall (not the box) the machine tries to boot immediately, then the beeping starts and then the USB error indicators flash up.

Reinstalling two sticks in (white) slots 1 and 2 and rebooting with an memtest86 floppy also confirms that there is only one stick installed whereas physically there are two.

memtest is till running with no errors detected: is there any point running this if there's only one stick being recognised?

It's looking like something is wrong with slot 1 ....
cheers

wrench97

No sounds like slot 1 is dead, have you tried 2&4?

andaluz

Yeah - they work fine: 1G restored.

I'm troubled by the Dell blurb about using slots 1 and 2 however I am more bothered by how slot 1 came to die? I hadn't done any maintenance in the box since before the hassle started and, to my knowledge, no one has kicked it or dropped it etc so ... dunno. I take it that this means a new motherboard if I ever want to use all four slots?

cheers

wrench97

Yes that means a new motherboard most likely there is a bad connection in or under the slot but it could be any where along the printed circurt.
Normally you would want to slots 1&3 as it's easier for the bios to find as long as the bios finds it in 2&4 it's better then only using half the memory.

andaluz

Thanks again wrench97: I'm going with 3&4.

Gutted, of course, as the thing's out of warranty :(

wrench97

Hey don't feel too bad your better off using 2 slots for memory anyway all you'll probably need is 2gig anyway and 2 1gig is faster then 4 512's and easier on the psu and the motherboard.

andaluz

Good point well made! :D cheers