"Paul" wrote in message
...
JFG wrote:
Hey, all,

I'm back with a problem that I hope is curable, but I fear the worst. I
was given a Satellite A45-S250 by a family member. It intermittently
booted up but didn't run for long. It had the problem of BSD after memory
dump on a regular basis. I looked up the error message and many
suggested bad RAM. I replaced the RAM with known good RAM and the
problem persisted. I disabled all the peripherals I could and tried to
load a fresh install of XP. This didn't work. Long story, short: I
thought I might have a burnt CPU so I took out the P4-2.8 Celeron that
runs at 533 and replaced with a P4 M 1.6 that runs at 400. According to
the Toshiba website the mobo should run either. I tried booting the
laptop with the 1.6 and it wouldn't boot. So I replaced the 1.6 with the
original 2.8 and now the laptop won't boot at all with the 2.8. It does
not go into the BIOS even though the lights come on and I hear activity
in the cd-rom. I fear that I might have blown the motherboard.

Anyway, if anyone has suggestions as to what I might do at this point
beyond getting a new mobo I'd like to hear them. Again, thanks to any
and all who take the time to suggest possibilities. JG

Examine the socket and the processor carefully, for connection problems.
If there is a lever, or a screw that clamps the ZIF socket into place,
make sure it is secure. Make sure the physical assembly was all put back
the same way (thermal paste, heatpipe heatsink onto processor, and so on).

The Celeron would not burn, because it would have THERMTRIP. If the
heatsink falls off, the THERMTRIP signal is available to kill power
to the processor. So in theory, you shouldn't be able to burn a
processor. Both modern Intel and AMD processors now have THERMTRIP.
You'd have to go back to some of the early Athlons, to find cases
where the protection is less than ideal. (My AthlonXP motherboard,
has a separate eight pin chip, which monitors the temperature and
does the equivalent of THERMTRIP.)

You can check for THERMTRIP, by downloading the datasheet for the
processor. One way to do that, is go through the list of Celerons
here, select an appropriate one, and then see of there is a documentation
link.

http://processorfinder.intel.com/

I wouldn't panic yet, because I interpret your results to suggest
something isn't assembled right. Like turning the screw on one of
those small ZIF sockets, to lock it.

Paul

Great post, Paul. Very good information. The cpu socket is one of those
with a lever. I checked the cpu itself for bent pins, etc and it appears
ok. It is locked tight in place and I'm pretty sure I put the cooler
assembly back correctly. You've convinced me that I haven't burnt the cpu
and now I'm wondering if I didn't do some harm to the motherboard. The
laptop wasn't working properly when I started on this project and now it
doesn't go to BIOS. I haven't completely given up on the one I have yet.
I'll try reassembling it today. I'm thinking that what I'll end up doing is
buying an equivalent unit from ebay with a broken screen and missing parts.
I'll cannabalize the one I have and make one good one. Thanks for your
response. JG