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Stumped, Please Help

Quick Recap:
My prob started with my PC not booting. All I would get would be the COMPAQ logo. At first I thought it might be a HD failure because of bad coincidences (like leaving a subwofer under my PC), but I connected both my HDs to another computer and they are fine. Then I thought it might be a PSU problem. But I was told if that were the case I wouldn't even be able to see the logo, it just wouldn't turn on. So I bought a PSU tester and I guess they were right. It showed no problems other than a bad floppy type connector that hooked up to a firewire that I don't use. This last part was today...
So what I tried, again don't know if it was a coincidence or not, was to not hook up this last cable. I turned on my power and my PC is up and running again. I don't think the prob is over tho because there are signs inside the case, as well as outside the case where the fan sits, that something overheated. There is black dust residue, like when wires or components burn up. I haven't tried to do anything heavy yet figuring that once I rev it up it'll go down again. Also, I noticed that my system info now shows a system bus of 100, where it used to show 400 (tho it should show 800, but that's another matter).
So that said, anyone got any ideas on what else I might look for?

COMPAQ Presario
P4 1.4GHz (400-800) BUS
300W PSU

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Lets review this a little.

In reply to: Stumped, Please Help

First, it would be nice if you told us what the last cable was that you didn't connect.

Re the black resdiue, if it was from burning, there is virtually always the characteritic odor that goes with it.

I know nothing about RDRAM, but I would think that the speed of that RAM determines the front side bus speed. I don't know if it gets two reads per clock or not, so I'm not sure about the FSB issue.

Did the system ever run at 800 MHz FSB? Should it with your memory??? If it is 400 to 800 that would mean that the 400 or 800 would be determined by what speed memory that you have.

I would think the running at only 100 MHz is a default safety mechanism, built in, such that if a bad shutdown is detected the system defaults to a very safe setting. [although I really think that it would be 200, unless that is the memory bus and it is double clocked like DDR and 100 memory bus is called 200 at the FSB]

Describe a PSU tester that somehow catches a bad floppy connector, wild! If you are only running at 100 MHz FSB, the CPU is likely running slower and thus consuming considerably less power. Possibly your Power Supply can't hack the full power configuration anymore. They do degrade, and 300 Watts doesn't give a lot of margin.

Really need to know what the last cable's function is.

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Inspect closely....

In reply to: Stumped, Please Help

You sure the "black sustance" is soot then you a real problem. If its just dust then clean/blow out and check the cpu setup is clear of any build-up. As for the black sustance, it maybe a blown cap, which can go but still boot-UP. However, if you reach a ceratin theshold, it fails as its overwhelmed. Find the true source of the black sustance, closely inspect and see any obivous damage, google for "bad caps" to see a picture of what to look for. Plus, if you didn't smell something burnt, maybe you're lucky and it's just bad looking dust.

As for your system 100 showing, check the bios area and reset to where it should be. It still quite possible the Compaq power supply still neds replacing as it maybe too stressed and fails when *all* connections are present. But, check the last connection(device) for possible failure itself.

tada -----Willy

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More Details

In reply to: Stumped, Please Help

To start, the bad cable I believe is called a 4 pin mini power connector. I have two of these, one for the floppy and the other for a PCI Firewire and front USB access card. It was the one connected to the PCI that was bad and left disconnected.

As for the residue, it is scorch black. I looked for any visible sign of a burned component like a cap but didn't find any, and I never heard that all too clear boom that tends to go along with blown caps. The residue sits on the case, in a gap between the edge of my mobo and the bottom vents of my PSU. There was a burnt smell, kind of like a cross between burnt wires and when you firs turn on a new electronic equipment (think new tv, theater sys, vcr, etc.) But the odor is now discipating.

About the RDRAM, it is supposed to go up to 800, both the modules and the PC specs confirm this, but every sys info tool that I use tells me I'm at 400. I stopped asking about this a while back because I kept getting differet answers, including the double clock that you mentioned. But in the end it just seemed like no one knew what the problem was and since my PC was working fine and without lags, I just left it alone. But now at 100, well it just won't do

Which brings me to the last point. I have noticed my PC has slowed down a bit. Specially during boot where it now takes about twice as much time to boot up. There have also been instances of 'hiccups' where it will slow down during very simple commands, like opening a menu. My pc has been up and running for almost 24hrs now and speed speed set aside, has not shown other symptoms of overexhaustion.

So if you have any ideas, I'd appreciate it. Oh, and one more question just to settle dissagreements. If a power supply goes bad, can it still draw enough power to power the mobo and nothing else?

||___________________....___|FRONT SIDE USB
||........................| | | |...|.........|
||....CPU..__........| | | |...|.........|
||............|__|.......| | | |...|.........|
||............|__|.......| | | |...|.........|

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Things happen(polite version)

In reply to: More Details

I've seen bad caps go and the power supply or device still work. It wasn't as critial unless it gets into the extreme end of what it was suppose to, noise suspresion. No matter, you really need to inspect and that means total teardown. If your capable, otherwise don't as things seem to work, BUT not up to 100%. Expect either a later failure and/or a more prominate state of the problem. In others, save your data, money and buy another system when you can. Electrical problems and/or thier related results cause secondary issues, so take the advice to heart and prepare. You may have isolated the power plug and device in question so limp along. Sad

good luck -----Willy

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Ah Willy, Willy, Willy

In reply to: Things happen(polite version)

Your words sound too true and yet I didn't want to hear them. I guess I was just grasping at straws hoping I could make it all better. For five years I've been keeping my system in shape, outperforming newer models, but I guess it was just a matter of time before something happened. Well, thanks for the time, time for me to look for a new pet.

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