Dimension 8400 wont start - rear LED are YYGG

Sounds like you've got at least one failed memory socket.

Have to somewhat agree with enj63 with a 'possible memory stick connector problem'. But there is one other possibility. The psu itself. with your description of  "some instances of very high speed fan noise, can only stop by power down", it could indicate that the psu is NOT receiving the (or acting upon the command signal) from the mobo. The next statement:

• Dell diagnostics reported one instance of error 3700:011B fan diagnostic.

• This again could be attributed to the psu not receiving or acting upon the correct error signal from the motherboard. This error signal originates from the power sensor's located on the motherboard and sends a command to the psu to either "shut down" or provide additional power/current via the other connector wires (main psu connector to the mobo).

  Now to agree with enj63, when additional sticks of memory are added the command signal to the psu is indicated and the psu responds. If you are (as you stated) are running find on 1 stick, memory stick slot 1, then your most probable cause is a "cold solder joint on memory stick slot2". THIS IS NOT SOMETHING THAT THE ORDINARY PERSON CAN FIX. Only a qualified computer tech can do this without causing all sorts of "major failures". I know, I have been fixing these problems for over 25 years.

  Take care and take a good look at getting a "Excellent" tech to check out the memory stick connectors.

  Lav

Maybe I don't understand, but are you testing with only 1 RAM module in slot 2 or 4, while slots 1 and 3 are empty? I don't think the 8400 will work that way. You need to populate them in order and in matched pairs. So, assuming they're all matching modules, put a module only in slot 1 and boot. If that works, test all of them alone in slot 1. If they all work in slot 1, put 1 in slot 1 plus 1 in slot 2. Test all of the remaining modules in slot 2. If you have more than 2 modules, test the remaining modules in slot 3 with the modules already working in slots 1 and 2. If all remaining modules work in slot 3, test again with all 4 slots occupied.

If the modules aren't all matched, you have to test in pairs so modules in slots 1 and 2 match each other, and modules in slots 3 and 4 match each other.

3 beeps or 1-1-1 don't appear as error codes in the 8400 manual, but you might want to reseat the video card in the PCI-e slot too.

The high-speed fan could just be the video card fan. They usually rev up until XP loads the video drivers. If PC fails to load the driver (failed POST, corrupted driver, etc) the fan will go faster and faster. Only way to stop is pull the plug. Yoy probably don't notice video card fan revving up during normal boot because it doesn't get going fast enough before the driver loads and takes control. That's why video card fan on my 8400 goes nuts during F12 diagnostics because the driver doesn't load.

Ron

Message Edited by RoHe on 02-03-2006 06:21 PM

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@Lavenir wrote:

Maybe I am missing seomthing from RoHe's post. I have two 8400's and NEITHER one of them have a video card fan. Just heat sinks. Unless your system came with an "additional" video card that requires a high speed fan, I am at a quandry as to what RoHe's response it referring to.

It is true that the memory sticks must be matched sets. If you have not changed the memory, then the original configuration (memory in slot1 and 3) SHOULD be ok. This does not preclude that changing memory sticks to (slot 1 and 2) could change the configuration. The 8400 requires that the memory be assigned slot 1, and with additional memory to go to slot 3 then 2 and then 4. Don't ask me why the specifications, but it DOES have to work with the memory controller module (the one that detects memroy/size and compatibility - which is on the motherboard). Slot 1 is the only position that does not require "comparative compatiatiblity, with other memory sticks involved. In orther words, it is the only slot that will work without any other memory installed. Test each memory card in slot 1, then install "GOOD" memory sticks in slot 1 and 3. If this continues to work, then install "good" memory into slots 2 and 4. Keep in mind that if slot 1 is empty your 8400 will fail. Again becaue of the above stated reason.

As RoHe stated, it could also be a video card problem (remote as it may seem), it still could be a psu command problem. try re-seating the video card.

One thing to try, is to place a bootable floppy into drive a and see what happens. But from what you have stated, not getting to any screen, I would first look at the cpu fan.

3 beeps are taken from a seperate diagnostic program that monitors the PCI slots. Without giving specifics (it takes a experienced tech to do this), it could be that your video AGP has had a failure, and as ReHo stated, it could be as simple as removing and re-seating the card. Keep Us informed as to what you find.

Regards: A 25 year computer tech

Lav

Maybe I am missing seomthing from RoHe's post. I have two 8400's and NEITHER one of them have a video card fan. Just heat sinks. Unless your system came with an "additional" video card that requires a high speed fan, I am at a quandry as to what RoHe's response it referring to.

It is true that the memory sticks must be matched sets. If you have not changed the memory, then the original configuration (memory in slot1 and 3) SHOULD be ok. This does not preclude that changing memory sticks to (slot 1 and 2) could change the configuration. The 8400 requires that the memory be assigned slot 1, and with additional memory to go to slot 3 then 2 and then 4. Don't ask me why the specifications, but it DOES have to work with the memory controller module (the one that detects memroy/size and compatibility - which is on the motherboard). Slot 1 is the only position that does not require "comparative compatiatiblity, with other memory sticks involved. In orther words, it is the only slot that will work without any other memory installed. Test each memory card in slot 1, then install "GOOD" memory sticks in slot 1 and 3. If this continues to work, then install "good" memory into slots 2 and 4. Keep in mind that if slot 1 is empty your 8400 will fail. Again becaue of the above stated reason.

As RoHe stated, it could also be a video card problem (remote as it may seem), it still could be a psu command problem. try re-seating the video card.

One thing to try, is to place a bootable floppy into drive a and see what happens. But from what you have stated, not getting to any screen, I would first look at the cpu fan.

3 beeps are taken from a seperate diagnostic program that monitors the PCI slots. Without giving specifics (it takes a experienced tech to do this), it could be that your video AGP has had a failure, and as ReHo stated, it could be as simple as removing and re-seating the card. Keep Us informed as to what you find.

Regards: A 25 year computer tech

Lav

Maybe I am missing seomthing from RoHe's post. I have two 8400's and NEITHER one of them have a video card fan. Just heat sinks. Unless your system came with an "additional" video card that requires a high speed fan, I am at a quandry as to what RoHe's response it referring to.

It is true that the memory sticks must be matched sets. If you have not changed the memory, then the original configuration (memory in slot1 and 3) SHOULD be ok. This does not preclude that changing memory sticks to (slot 1 and 2) could change the configuration. The 8400 requires that the memory be assigned slot 1, and with additional memory to go to slot 3 then 2 and then 4. Don't ask me why the specifications, but it DOES have to work with the memory controller module (the one that detects memroy/size and compatibility - which is on the motherboard). Slot 1 is the only position that does not require "comparative compatiatiblity, with other memory sticks involved. In orther words, it is the only slot that will work without any other memory installed. Test each memory card in slot 1, then install "GOOD" memory sticks in slot 1 and 3. If this continues to work, then install "good" memory into slots 2 and 4. Keep in mind that if slot 1 is empty your 8400 will fail. Again becaue of the above stated reason.

As RoHe stated, it could also be a video card problem (remote as it may seem),

Maybe I am missing seomthing from RoHe's post. I have two 8400's and NEITHER one of them have a video card fan. Just heat sinks. Unless your system came with an "additional" video card that requires a high speed fan, I am at a quandry as to what RoHe's response it referring to.

It is true that the memory sticks must be matched sets. If you have not changed the memory, then the original configuration (memory in slot1 and 3) SHOULD be ok. This does not preclude that changing memory sticks to (slot 1 and 2) could change the configuration. The 8400 requires that the memory be assigned slot 1, and with additional memory to go to slot 3 then 2 and then 4. Don't ask me why the specifications, but it DOES have to work with the memory controller module (the one that detects memroy/size and compatibility - which is on the motherboard). Slot 1 is the only position that does not require "comparative compatiatiblity, with other memory sticks involved. In orther words, it is the only slot that will work without any other memory installed. Test each memory card in slot 1, then install "GOOD" memory sticks in slot 1 and 3. If this continues to work, then install "good" memory into slots 2 and 4. Keep in mind that if slot 1 is empty your 8400 will fail. Again becaue of the above stated reason.

As RoHe stated, it could also be a video card problem (remote as it may seem), it

Thanks to everyone for your replies. Apologies if my original post wasn't clear.

The machine was happily working with a memory stick in all slots, original config was 256MB stick in slots 1 and 2  and then expanded with the addition of 512MB sticks in slots 3 and 4. Total of 1.5GB using all four slots. It worked this way for many months with no issues.

All of a sudden while working at the computer it started beeping, dropped to black screen and wouldn't boot from that time onward.

Using the rear LED error codes, the manual instructed to test the memory sticks. All sticks test ok in slot one.

When I add a known good stick to slot 2 to get the minimum memory config of sticks slot 1 & 2 the problem is evident. 

If I have a stick in slot 1 and 3 the computer boots ok, adding a stick to slot 4 makes it fail. Hence my conclusion that a problem exists with slots 2 & 4.

I guess I'm after some suggestions or validation of what the problem may be. When Dell comes back to me, I'd like to be able to validate their answer.

charlie_bird,
OK, I got it now. All memory modules work in slot 1 and slot 3. And I presume the video card (assuming you don't have integrated graphics) is funtioning OK when it boots with a stick in slot 1 alone, or in 1 and 3. Sounds like the mobo may have failed. Doesn't sound like power supply because you say it runs ok as long as slots 2 and 4 are empty.

Boot the system with 512MB stick in slot 1. Press F12 before XP starts to load. Run all the diagonstics. See if it reports any errors. If not, you still may want to pull out all the PCI cards and see if it works with matched memory in slots 1 and 2.

And if not, you may have to buy a mobo either from Dell Spare parts or Centrix:
http://www.centrix-intl.com/list.asp?CategoryID=60

My 8400 has PCI-e nvidia geforce 6800 vido card with a fan mounted right on the card. Maybe some other video cards Dell offered in the 8400 don't have fans onboard. Until the nvidia video driver was fixed, an error caused the 6800 fan to rev at high speed as soon as PowerPoint or Java started running. Very loud and very annoying.

Ron

The X300se was an option for the 8400, & its a fanless card.
At least the one that  I got in one of my 8400's was
Bob

Had similar problem.  Many hours with Dell Chat and three visits by Dell techs, two new motherboards and replaced the Thermal Unit.  I am a novice and don't really understand these terms, but after Dell failed.  The computer would start for a while and then stick on start up.  Then the terrible Ithr message.  My neighbors teenage kid told me to unplug the monitor and turn the computer on and plug the monitor back in.   Don't know why, but the error message is gone and the computer starts.  Hope it helps.  can't explain why, but it worked for me. 

Replacing the motherboard fixed my problem.

New OEM Dell motherboards for the 8400 are only $39 with 90-day warranty, here:

http://www.centrix-intl.com/

Ron