No Boot on Dell laptop

[oseney]

My Dell Latitude LS500 P3 laptop has suddenly stopped booting. No POST. Nothing on screen. Only the fan and HD run. 3 LEDs blink once - then nothing. I've got it apart and disconnected everything. No keyboard, HD, memory. Still no good. Put memory back - no good. The memory is checked on another machine, the power supply also, (it's running off AC supply). I've been reading some posts which refer to "clearing the CMOS". There is no jumper on the mobo to do this, removing the CMOS battery and leaving for 48 hours does nothing. To help me with the "clear CMOS" problem, can anyone tell me where this is likely to be - is it a separate chip or part of the processor?

 

[bcastner]

You can do it with a paper clip --

http://qasimtoep.tripod.com/dell/dell.html

But I would not. It is very unlikely this is the problem.

 

[oseney]

Thanks bcastner. Your site is v good. My Latitude LS is not quite the same as the L400 you cover and doesn't seem to have the 8 pin CMOS chip on the back of the mobo. Also, the chip you arrow as CMOS sems to be a flash programmable EEPROM, so would be unaffected by the presence of the battery - or am I up the wrong tree here?

 

[bcastner]

The wrong tree is looking to BIOS defaults to sort the non-boot issue.

Did you have any fan issues, or have a temperature monitoring program installed? My guess is your processor was heat damaged.

There were some Dell latitudes that would not go back out of S3 suspend state, and required a BIOS upgrade. But you could eventually get them to POST.

My guess -- processor failure due to a faulty fan or fan logic circuit.