Hello everyone. A friend of mine gave me her HP ze2000 to try and fix. It powers on but seems to be continuously rebooting. What happens is a few seconds after pushing the power button the scroll lock and caps lock LEDs flash simultaneously once every one or two seconds. This flashing just continues indefinitely. So far I've broken the computer down completely to just the motherboard and removed the RTC battery to reset the CMOS but the problem is still there. Most of the motherboards I've worked on had a thermal management IC that will shut the comp down if it overheats. Judging from past experience of working on another friend’s laptop, I think that IC might be bad and causing the continual reboot. Does anyone have a description or a list of the different motherboard components? It would save me a lot of effort. If I can't find detailed info on the motherboard components and layout, I'll have to track down datasheets on the parts one by one (very tedious). Anyway, if anyone has any info they think might be helpful or if you have any suggestions about how I should be attacking this problem, please let me know. Your help is greatly appreciated. Thanks.

. how far into a power on did it get before rebooting?
. bios setup screen?
. windows?
. beep/noise?

cheers ...

Download the maintenance and service manual from HP and that will give a complete break down of everything including part numbers. And also how to break it down.

http://h10025.www1.hp.com/ewfrf/wc/m...&lang=en&cc=us

If the laptop is going into the Windows and keep rebooting them you have a problem with Windows.

If your laptop keeps rebooting before getting into Windows than you have a hardware issue. Either BIOS related or physical hardware. Like you said CPU overheating is a common issue. Have you replaced or changed any physical hardware lately. Maybe something became ajar. Heatsink not secured properly, fan not working. If it was the CPU the system should automatically shutdown not reboot to protect itself from burning up.

qhn:

. how far into a power on did it get before rebooting?

The boot sequence doesn't get very far. Immediatley after pushing the power button the CPU heatsink fan turns on for ~1 sec and then turns off. Then there is a 1-2 sec pause before the scroll lock & caps lock LEDs begin simulataneously flashing once every 1-2 seconds. That's as far as it gets.

. bios setup screen?

No, it doesn't get that far.

. windows?

No, it doesn't get that far.

. beep/noise?

No beeps are heard during the computer's attempted boot.

blackace:

Thanks for the link. I actually already found the service manual, that's where I got the disassembly instructions from. The service manual does have a parts list but the level of detail is not that great. It does have a part number for the system board but doesn't descibe individual components on it. The comp isn't even getting to the BIOS screen so I agree with you it seems like a hardware issue. I also agree that an overheat condition should cause a shutdown and not a reboot. I just thought that maybe if the thermal management IC was faulty it might cause that behavior. But, that was just speculation. As for a loose heatsink, etc, I didn't do anywork on the comp before it failed. According to the owner, she closed the lid on the comp before going to bed for the night and when she tried to use it the next morning it was very hot and it would not respond to input. She then rebooted it and that's when the problem began occuring. It sounds like what happened to me is that for whatever reason, the comp never went to standby completely when she closed the lid and it overheated.

If it is a BIOS problem, how can I flash it in it's current configuration? Is an ICSP connector or test pad typically somewhere on the system board?

Thanks everyone for your help.

how about trying to start the comp w/o:
. the ram installed
. the cpu installed

cheers ...

I've already tried it without the RAM installed, no luck. I'll try taking the CPU out and report back the results. Thanks.

OK, just tried it without the CPU or RAM with no luck.

Well, it is not an over-heating issue, and I do not think that it is a thermal management problem.

Not impossible that there is a bad ram board, very possible that there is real motherboard damage.

I would suspect the motherboard. Since the fact that it still does it and you have exhausted everything. A most common issue for rebooting is a faulty power supply. Since it uses an ac adapter and has dc converter board (if it has one and not built in) the only other possible thing I could thing would be the dc converter board. But normally when they go you either have charging issues or no power at all to the system. That's why I suspect the motherboard.

VNE147: I encounter the exact same problems with the same model. How did you deal with your computer fininally? Thanks.