In article ,
"Michael A. Terrell" wrote:

Karl Townsend wrote:

On Fri, 16 Nov 2012 17:53:26 -0500, "Michael A. Terrell"
wrote:


Karl Townsend wrote:

i had a CMOS checksum error on my CNC mill. So, I installed a new
motherboard battery. Now the CPU fan just comes on and it makes no
attempt to boot. Is the computer DOA? I checked connections and
wiggled stuff.


Remove the new battery & short out the socket for a few seconds, then
reinstall the battery. You may have some corrupt data in the CMOS
scratchpad RAM.

tryed that, No Joy


Try another power supply, if you have one. You may have a dying or
dead motherboard. Unplug all the drives, and cards except the video
card, if it isn't part of the motherboard. If you can't get the bios
screen to flash, look at the electrolytics on the motherboard, and the
ones near the processor in particular.

If they are bulging, they need replaced, or replace the motherboard.
They are a special low ESR 105° C type capacitor, and not always easy to
replace, because they are soldered to internal layers. If you can find
the exact same type motherboard, and move the processor to the
replacement board you shouldn't have to reinstall any software.


A good article on bad (bulging) electrolytic capacitors, causes, and
good photos can be had he

http://en.wikipedia.org/wiki/Capacitor_plague

Looks like one major cause of many failed units started roughly around
the early 2000's, and traces back to a botched industrial espionage
episode. Details are in the the above article.

Erik