Do not go half wild and start replacing things. Are
voltages within limits as reported by a 3.5 digit multimeter?
Especially voltages on red, orange, and yellow wires must be
within upper 3/4s of limits in chart. What does Power Good
signal say?
Procedure and chart to verify power supply limits and
handshake signals is:
"Computer doesnt start at all" in alt.comp.hardware on 10
Jan 2004 at
http://tinyurl.com/2t69q or
"I think my power supply is dead" in alt.comp.hardware on 5
Feb 2004 at
http://www.tinyurl.com/2musa
Once power supply is proven good or bad, and necessary
handshake signals are provided, then strip down motherboard
only to CPU and speaker. Yes, disconnect keyboard, Ram,
peripheral cards, disk drive, mouse, etc. Computer should
power up enough to only beep speaker. If no sound, then you
have isolated problem down to motherboard and CPU. As another
noted, CPU is rarely a reason for failure. More often than
CPU failure is one created by standoff that was improperly
mounted and broken through solder mask. I am not even saying
this is the problem. Only demonstrating one in a long list of
reasons why motherboard and CPU would not beep speaker.
Furthermore, if CPU is damaged, then most likely motherboard
is also damaged.
Dirty little secret about plug-in protectors. They can even
contribute to damage of a powered off and adjacent computer.
They provide transients with destructive paths that bypass
power supply to damage motherboard, modem, etc. If a plug-in
surge protector were so effective, then those $0.10 parts
would already be inside the power supply. Why are those $0.10
parts not installed? Once they were. No longer because those
$0.10 parts (that cost tens of dollars inside a plug-in
protector) are not effective when adjacent to the computer.