Dell Dimension 8400 wont boot up

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I really empathize with you - I know this must be very frustrating and unfortunately I have no great insight.

When you took out the old mobo, did you notice any burn marks near the PSU connections on the mobo? Did you check them connectors on the ends of the cable from the PSU?

While you are continuing to troubleshoot, are you using only the old or new memory and trying both? Please list old and new memory - brand, model, and size.

Do you have another PSU you can try - maybe borrowing a friends?

Have you disconnected (both from mobo and PSU) all non-essential equipment while troubleshooiting - for instance all USB devices and even the optical drive.

Do you have any non-stock components?

You might go through the boot issue thread -even tho it is more for new builds. But it might be a good check list or provide some idea.

http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems

If you don't get many other responses, you might start a new thread. Some people may be avoiding this thread since it is so old.
 
Hey, ill try to keep this alive for anyone who still has questions with the 8400. I own the same computer myself and its been running strong for 7 years. I have had almost every problem everyone else was having except i never had to replace the motherboard or CPU.

rcantu329, you seem to have lost all control with the power buttons. Could you check and make sure that you have reconnected the USB 2.0 cable? It connects on the bottom right of the motherboard. And check all of the pins. My issue was that it slightly came apart at the base of the cable so if you could inspect that and tell me if that helped at all. The problem is that there is no power so don't go inspecting the memory.

And a dead processor will not keep it from powering up. Only a broken power button. So try that and tell me if any of this helps.

Do any of the fans turn on? Or was no sign of life literally nothingy
 
I saw that, but I would just like hum to check the cables to it, and if that's not it, then its most likely the PSU. Though if the power light on the motherboard comes on... i wouldn't exactly say the PSU... There is the chance that the motherboard is dead, even though he just got it.

But the most you can do is check that USB 2.0 cable. If you pull it off just slightly in any kind of wrong way, its damaged. I have no clue why its designed like this. Its kinda like those void stickers. You take it off and they know that it was tampered with. That's all i can say here. I'm only 15 but doesn't keep me from knowing some things about this computer.
 
Rcantu did not say what power light he was talking about, but the only light listed in on the mobo diagram is for "auxiliary power". I am not sure what the means but suspect it might be the on-board battery and have nothing directly to do with PSU status.

Perhaps Rcantu could look at his board and tell us - except that he has not posted since his original post 2 weeks ago so it appears he has deserted this thread. Let's hope that means he has solved his problem - whatever it was.
 
http://www.ascendtech.us/itemdesc.asp?ic=MB4DELJ3492&eq=&Tp=

I found a link for a replacement OEM motherboard for the 8400, its listing at 119.99 i think. I just bought a 30.00 motherboard thats comparable. i should get in a few days. I will let you know how that works.
 
I checked the "P2" connector as jlcoleman suggested some months ago (may 17,2009)

It was just like his in the picture. I used a paperclip to clean the plug and pin (crude I know but it worked - though the oxidation has me concerned about future longevity!)

P2Plug-BurntUp-sm.jpg


Plugged it back in and voila .... the PC breathed again!
 
The reserve battery is almost always the problem. There is a little access panel inside the battery compartment that it hides behind in most cases. My old D600 wouldn't power up either, so I started on a hunch. It worked for me.

1. Remove all batteries and unplug wall adapter.
2. Wait 15-20 minutes
3. Open inside access panel and remove this little dinky battery with 2 wires and a plug that goes to the motherboard.
4. Go on ebay and order a battery.

Now, if you want to put a little tiny charge, like you would to jump start a car, on the dead battery, that can be done. It won't last long, but if you have data you have to get off ya just don't turn off the 'puter 'til you get it.
Email me for a picture of how that can be done very simply. I'd be willing to bet that techs get a hundred bucks for this little hack, and it is so easy if you have ever put batteries in an ipod you can do it. :)

Email fiftymegs at juno dot com for photo.
 
The reserve battery is almost always the problem. There is a little access panel inside the battery compartment that it hides behind in most cases. My old D600 wouldn't power up either, so I started on a hunch. It worked for me.

1. Remove all batteries and unplug wall adapter.
2. Wait 15-20 minutes
3. Open inside access panel and remove this little dinky battery with 2 wires and a plug that goes to the motherboard.
4. Go on ebay and order a battery.

Now, if you want to put a little tiny charge, like you would to jump start a car, on the dead battery, that can be done. It won't last long, but if you have data you have to get off ya just don't turn off the 'puter 'til you get it.
Email me for a picture of how that can be done very simply. I'd be willing to bet that techs get a hundred bucks for this little hack, and it is so easy if you have ever put batteries in an ipod you can do it. :)

Email fiftymegs at juno dot com for photo.
 

Hmmm. Why dig up an old thread to post misleading information?

The last poster before you showed pictures of his burned mobo power connector. And you say the problem is almost always the reserve battery?
Posters before that guy hare reported all kinds of problems, some have found burned connectors or what appear to be blown capacitors, most have long since checked their batteries and found them not to be the issue, and were investigating mobo, psu, and other fixes.
 
I have been through 5 different Dell machines and seen this issue. 2 of them were given up as hopeless by so called "techs" that examined them. Misleading? Not intentionally. If you saw it happen 5 times on different machines would you also tend to look there first?
 
I had the same type of problem with my Dell 8400...that last issue being that it would no longer power up at all. The power light on the mobo was on, but that was all. I didn't feel like figuring it out so I took it to our local Dell authorized computer repair business and paid $39 to have them diagnose the problem. Turns out it was the mobo with bad capacitors (you can see one with an evident bulge in the top).

In any case, I have been sitting on the system debating whether it would be worth it to replace the mobo so I can have a spare PC to perhaps just use as a pseudo-server or such. After reading this overwhelming forum thread, I am even less sure if it is worth the $89 or so to replace the mobo OR $100 to get a new box, mobo, and cpu and strip the components out of the 8400 for use OR just let it sit around for spare parts until it would be useful no longer for such. The fun...

BTW: After my initial crap Packard Bell PC back in the day, I have had nothing but Dell computers (laptops and desktops). Other than the 8400 going out on me after 3 years, I have never had any other problems with any of my Dell computers....currently running 2 laptops and 3 desktops in the house...all Dell...and only replace a system when it gets too old and I want the latest (or close to the latest).
 
Hi guys, adding my two cents.

For the past six months to a year, every time the power goes out at my place, it's been a bitch to restart my 8400. At first I thought a surge killed everything, but it turns out the front power button is just crappy.

At first, if I just jammed and jammed on it long enough, eventually it started.
Later, I had to rip off the plastic button and use tweezers to get the switch to depress.

Now, that trick isn't working anymore. I've searched exhaustively for the pinouts on the m5989 or the power button controller or the motherboard but no dice yet. Any suggestions on which pins to connect to jump start this baby would be appreciated. I'm 98% sure the rest of the system is just fine--this is a repeated issue with the power button.

Thanks,
Todd
 


Wow, exact same things happened to me a year or two ago! I don't have a Dell Dimension though, I have a Dell Dimension XPS Gen 4. Scared the hell out of me. I was later able to get it to boot, and no problems. Called Dell and mentioned what happened and they offered to send me a new computer. I have so much software installed many of which have several customized settings. Add to that the fact that I use my computer for my home business and I actually declined the offer much to their suprise. Strange, when I described my problem, the tech support guy gave no indication of being familar with this issue and yet so many people here have described something similar to what I experienced.

In my case, I think I was playing a game at the time the problem set in. I looked around and at the time the only references I found to what I had described had as the solution to check the dust in the video card fan. Sure enough, there was a lot of dust (pretty much only confined to the video card though). I'm guessing that led to overheating which led to some other problem. My computer is on 24/7 so that's a bad combination to have with dust.

I do have one lingering problem though. If my computer ever freezed or I get a BSOD, if I have to hold the power button to shut down, I get that supersonic fan speed which sounds pretty scary. After reading all the posts here, it seems the likely culprit is one of the following:

1. p2 connector
2. power supply (or power supply internal fan)
3. motherboard
4. video card fan

Given the fact that my computer runs fine aside from this one situation, can I rule out the motherboard? Also, I ran all the Dell diagnostic tests and all of them passed, including the fan tests. I opened the computer and looked for a burned p2 connector but all I could find was a p5 connector which wasn't burned. I DID find a capacitor that was bulging at the top (umbrella shaped top) instead of being flat with a bit of brown metallic crust at the top, kind of like what you might see on top of a battery. Nothing major, but it was noticeable. The capacitor was in slot C4J2 on the motherboard. The brand name of the capacitor is Nichicon and it has HM(M) 2200 written on one side and H0501 written on the other side.

Does anyone know how dangerous it is to have a bulging capacitor as described above? Note that the computer works fine aside from supersonic fan speed if I am ever forced to power the computer off by way of the power button. Would it best for me to contact Nichicon or Dell?

Thanks in advance,

HP
 
I'm joining the army of unhappy Dell 8400 owners.

Same problem, super speed fan (I didn't know the thing could rev that hard), amber light, no beeps, no nothing, very black screen.

Have done all the tests, everything's good. New battery. Cleared CMOS. Replaced fan, with a new louder version(?), tried human sacrifice, no deal.

Seems to me that it is heat sink/CPU related. If I apply serious pressure to the heat sink I can occasionally get a clean boot, if I miss it we're back to the fans of death again.

Rip off your heatsink and have a close look at it. If I lay a straightedge across mine I swear it is a little bowed in the center; as in the mounting edges are lower than the copper.

I'm wondering if that is causing a certain amount of gap tween sink and cpu, bigger than can be bridged by thermal paste. Possibly, pushing down on the heat sink may be forcibly closing the gap a bit?

Next time I shut this thing down, or we have a power failure (8400 owners know to never shut it down) I intend to get at the alloy edges of the heatsink with a file to see if it makes any difference.

I want to get mine back to the point where it will error if there is no CPU fan detected. That way I can take this killer fan out and add a couple of Noctua's directly to the heat sink instead. There is a certain amount of satisfaction in pushing F1 to ignore.

In anticipation
Bruce

 
I have had this same problem with my 8400. It has been very intermittent. What I have seen is that if I put my system in Standby mode, then come out, that is when the system locks up and the CPU jet fan takes off. Changing the suspend mode to S1 (mine was previously S3), seemed to eliminate this particular (standby) problem. Not sure if this leans towards a hardware issue or something else. Thought I'd post to see if this helps out.
 
I've noticed a pattern with my system, atleast every 2 years I get weird power offs and restarts. /i've had my mobo and psu replaced, and it would work fine.
 
But it is almost always just a battery problem. Just ask Dougger. He knows. He has the answer for everyone because they all must be having the same minor issue he had. The the roaring fan, the burned P5 connector, the bulging capacitors, the startup that works when you press down on heatsink - these are all caused by a bad battery. Just replace your battery and everything will work fine. Just ask Dougger.
 
DELL 8400 WITH FAN RUNNING LIKE JET ENGINE PROBLEM IS THE BAD CAPACITORS ON MOTHERBOARD NEAR THE PROCESSOR, YOU HAVE 8 CAPACITOR IN LINE I HAVE THE 820 MICROFARAD 4 VOLT THEY DID NOT BULGE ON THE TOP BUT THEY POP OUT ON THE BOTTOM ITS HARD TO SEE WHEN YOU LOOK BUT TAKE THE FLASH LIGHT AND POINT TO CAPACITORS DON'T BUY NEW PSU, OR NEW PROCESSOR ONLY REPLACE THE BAD CAPACITOR AND YOU WILL HAVE NEW COMPUTER FOR YEARS THAT IS MY ADVICE GOOD LUCK WITH DELL,AND THE CAPACITORS COST ONLY 14$ FOR 8 CAPACITORS!!!!!!
 


Just experienced this same problem - and am trying to find a pinout for the W1158 power button/hdd led/pwr led board to just jump start the computer so that I can get to the bios to power on after ac. Was on teh phone with Dell and they will not divulge anything. The ribbon from the power button goes to front panel board which includes USB and headphone jack. There are 15 pins from the power switch to this board. From there, a 34 pin ribbon (2 blanks, I believe) goes to the motherboard. Just want to power the unit on. Any and all help greatly appreciated.
 
Is there any update (resolution) to this problem? Seems that nobody has been able to nail down what the exact problem is or the proper solution.

Thanks.
 
OK, I have a question in a similar but slightly different direction.

I just inherited a Dell 8400 and almost immediately started having the same problems as everyone else who has posted here - erratic fan speed, intermittent and random shutting down, won't reboot, etc. I started surfing for answers and found all the solutions listed herein, all to no avail. I've reseated boards and processor, cleaned and reseated the heat-sink with fresh silver thermal paste and recited incantations over chicken entrails under a full moon. The only thing that works with even occasional 'consistency' is pulling the A/C cord out of the power supply after I've shut down for the night. In the morning, I turn on the monitor (so there's no surge, no matter how slight), plug in the power and punch the button. This works between 57% and 78% of the time, if done between 7:36 and 8:13am EDT with the inside temperature at 73.2 degrees Fahrenheit and humidity of 64%. And I do have to be standing on one foot (the left one) while facing the nearest Wal*Mart. No real problem, but I would like to up my successes a bit.

So, here's that question: Why, considering that the first posting in this forum was September 2006 and the last one was, well... tonight, March 31 2010, has Dell chosen to not do a darn thing about their flaky, bastard step-child 8400? I haven't seen anything to indicate that they've even acknowledged the multitude of problems, much less addressed them or suggested any solutions (and heaven forbid they should accept any culpability).

Has anyone ever actually gotten a complete resolution and/or satisfaction from Dell or is it time to call our local Congressman (or maybe class action lawyer)?

Just my two cents worth... HEY, maybe the Dell 8400 was THEIR two cents worth!!! (and overpriced at that.)
 
I've read several of these threads and I seem to have a different issue with my 8400... My computer will just go black... Whether I'm working on it or not, I could walk back in the room and the power light is blinking amber... Or, I'll be right in the middle of something and BAM gone with the blinking light... To boot back up, I need to turn off at the power strip as well as unplug the ac adapter from the back of the tower for a few moments...

I don't hear any weird fan noises or anything like that. All 4 lights on the back are solid green.

Power supply issue? Something else?

Any insight is appreciated...

Scott
 
I’ve had the same amber light problem on my Dimension 8400. The amber light usually occurs at the first startup of the day (I cut the power off overnight). The system also randomly freezes - the power light stays green, the mouse & keyboard lock up, the CPU fan shuts down, but the PSU fan continues to run. It won't turn off down through the power switch. I have to pull out the plug to shut it down.

My P2 connector is charred on pins 1 & 2 (#2 is worse than #1, it's almost black). I removed the PSU yesterday morning and scrapped the P2 with a paper clip as suggested on this forum. I also checked the pins on the mob and they appear to be okay. It ran fine all day. I shut it down (complete power cutoff) around midnight. This morning the amber light came on when I hit the power button. I held the power button until it shut off and wacked it on the side that holds the mob. I was able to power up after that. However, it froze up twice so far today. I removed the P2 both times and it restarted when it hit the power button.

I bought the PC in June 05. The system froze and the amber light came on in Dec 07. Fortunately, I had the extended warranty and Dell replaced the mob. I started having problems again in Aug 09 and brought it to a local shop. They charged me $80, couldn’t identify the problem, but got it working. Ran okay until Feb of this year.

My guess is that the charred P2 is causing the problem. The overnight cool-down may cause enough contraction so that the charred sockets don’t provide enough juice to the mob. Maybe a similar displacement when the system is hot.

I plan on replacing the PSU with an Athena Hercules 400W PSU since I don’t want to spend much (I had an HD problem last month and spent about $300 on diagnostics and HD replacement. I want to avoid pouring more money into this dog). I can get a new Hercules for about $30 on eBay.

http://www.athenapower.us/products/power_supply/ap_mps3atx40.html

My question is: will replacing the 350W PSU with a 400W unit prevent the P2 from burning up again?

Also, can anyone comment on the 400W Hercules?
 
I've had this happen to my 8400 yesterday. Worked fine in the morning, then came to boot it up in the evening - nothing!
Took the main power cable out of the back several times and every so often it will have a little power up (fans run and the light on the front comes on, but then powers off again).
Tried several things suggested on this board, but nothing.
The only way i can get it to run it to take out the battery on the motherboard and put it back in. This seems to work for now,
Anyone got anyother suggestion of things to try.
I've had my 8400 since 2004 and its been perfect up to now, so would hate to have to replace it!
Thanks
 
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