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UncleAndy

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Laptop will not start, probable MoBo or CPU failure..

Hi,

my laptop just died on me the other day and after popping it open and messing around a bit I sort of came to the conclusion that it is either the CPU or something on the motherboard (an onboard device or the motherboard itself). This laptop was bought in May 2002, and from a supplier (that sold the same computer 2 years ago) I was told that I had to find a standard Intel P4 1.6 - 2.4gHz CPU (for desktops, it was one of the desktop replacement computers with normal CPUs) - which is a bit of a problem unless I go for the eBay solution or find a second hand shop somewhere. Anyway, I just want to bounce a few ideas with you guys in case I have overlooked something. How can I be sure it really IS the CPU? Or the motherboard? I dont want to go out and purchase a $150 CPU that I might not even need,and I am having trouble finding anyone I know that has one of these in their computers so I can try it first. When I turn it on I can detect SOME sort of life, because the ON light comes on and the fans react but moves only slightly before they stop. I have tested the memory chips (2x256MB in there, tried both on their own in both sockets - nothing. Unless they BOTH blew at the same time, but that's unlikely), and the harddrive is still ok. I tried to take the processor out and start it again, and it still acted the same way (not sure if that means that it's screwed and that the motherboard reacts this way with a defect CPU, or if the CPU is fine and there is something else and that it at this time doesnt matter whether or not the CPU is in there..). No beeps, no nothing. Its just dead, except the green ON light, that will be turned off again if I turn the computer off again.

My laptop is able to play music CDs without the computer actually being turned on, and has Play, Stop and the other buttons needed for this on the front panel. I have tried to put a CD in and it played it without any problem. The sound obviously comes from the soundcard and out the mini jack output, so I know for sure that it still works, and I assume that the motherboard has SOMETHING to do with this feature and it gives me hope that it still works. I also assume that the powersupply works since the ON light works and the thing is able to play CDs.

Am I right to think that it is likely to be the CPU? I can try to rip the network card out, but I am afraid it's built in on the motherboard.. I've tried to start it without the battery in (on external power), without the DVDROM, without the disk drive and without the harddrive - no changes.

Any good ideas! Anyone ever experienced this?

Thanks!

Andreas
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rid
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I had a similar situation at one point. After some extensive tinkering it became clear that the CPU had a tendency to unseat itself, probably due to thermal creeping or similar phenomenon. Re-seating the CPU got the laptop going for a few weeks until it was time for surgery again. The problem appeared first time when the previous owner let the machine sit powered on overnight, with air flow from vents partially restricted; I think something was slightly warped because of the heat. However, re-seating and blocking the CPU in place cured it. I had to reset CMOS, too, to make it startup at all.
/RID
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ChrisSchumann

As for playing CD's: Playing CD's with the power completely bypasses the CPU of the computer. The CD drive itself has a tiny computer and uses its analog output to send audio to the mixer and the headphone output.

It is possible that the motherboard is shot while your CD player cranks out the tunes.

If your machine truly has a normal P4 CPU, you should be able to put it in a wide variety of desktop machines. Ask a local PC user group if they can help you out. (Linux users are particularly eager to take their machines apart.)
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OK, I will see if I can reset the CMOS and make sure the CPU is attached properly (which it should, I took it out and put it back in several times). I am also tracking down someone that can test my CPU in their computer / let me test theirs in mine.

Chris: I was afraid someone would say that the motherboard could be dead while the CDs still worked! :)

A.
Hey I have another question.. My CPU requires a Socket 478 (Intel Pentium 4, 2nd gen.). What happens if I put any Intel P4 CPU of that type in there? I was told I needed a 1.6 - 2.4mHz CPU - does that mean a 2.6 wont work, or that a 2.6 will run with a maximum speed of 2.4mHz?

Thanks!
There are different (VERY different) kinds of P4. Some of them have a 478-pin footprint, some do not.

Of those that DO have 478 pins, some run their bus at 400MHz, some at 533MHz and some at 800MHz. Your CPU should match your bus speed. A slower CPU will not work, and a faster CPU may run at the slower speed, but it will be more expensive.

Further, your support chipset (like 845P or whatever) expects a certain type of P4, so it's safest to just get what is known to work.

That being said, this may be a good time for an upgrade. I have a motherboard at home with a 1.7GHz P4, socket 478, running at 533MHz. I plan to put in the fastest CPU for it, which is the 2.8GHz/533, NOT the 2.8GHz/800.

After days and weeks of searching I found that the power supply had some problems - so nothing wrong with the CPU. Thanks for all the help, I really appreciate it!

Andreas
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DarthMod
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