4pin pentium power connector scorched - computer shuts off - blinking amber instead of green light

  • Thread starter Thread starter Bill Gates
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Bill Gates

It's a Dell sc420 server. It's run good for a year now. Suddenly it
shuts off with a blinking amber light on the power switch. (Amber
blinking indicates that the system is powering up.) I pulled
everything from the motherboard and found the 4 pin 12volt power
connector was scorched brown. I reseated everything and it powered up
fine. Few weeks later it does it again.
Bad Power Supply What could a PSU do to cause charing on the 12 v
lines?
--
Bad CPU
--
or the connectors are charred heating up?
I've cleaned the connectors. maybe I need ro replace them?

http://www.hardwarebook.net/connector/power/atx12v.html

http://dtr.bjash.com/Dell Service Provider Training/PowerEdge SC/PowerEdge SC420/led.HTM
 
Bill Gates said:
It's a Dell sc420 server. It's run good for a year now. Suddenly it
shuts off with a blinking amber light on the power switch. (Amber
blinking indicates that the system is powering up.) I pulled
everything from the motherboard and found the 4 pin 12volt power
connector was scorched brown. I reseated everything and it powered up
fine. Few weeks later it does it again.
Click to expand...
Bad Power Supply What could a PSU
do to cause charing on the 12 v lines?
Click to expand...

Supply a lot more than 12V on those lines.

Its more likely to be due to bad caps on the motherboard.
 
Bill said:
It's a Dell sc420 server. It's run good for a year now. Suddenly it
shuts off with a blinking amber light on the power switch. (Amber
blinking indicates that the system is powering up.) I pulled
everything from the motherboard and found the 4 pin 12volt power
connector was scorched brown. I reseated everything and it powered up
fine. Few weeks later it does it again.
Bad Power Supply What could a PSU do to cause charing on the 12 v
lines?
Click to expand...
<snip>
It appears that your 12v line has overloaded. Everything is most likely
fine, but your motherboard doesn't have enough 12v connectors. If you're
running multi-processor, consider taking at least one out.

poly-p man
 
<snip>
It appears that your 12v line has overloaded. Everything is most likely
fine, but your motherboard doesn't have enough 12v connectors. If you're
running multi-processor, consider taking at least one out.
Click to expand...

I don't have enough 12v connectors?

Why would I need more? There is only one CPU. This is the extra 4 pin
power connector for the CPU. Why would I need more power? I'm of
course assuming Dell designed the server to cope with a P4 2.8Ghz
processor.

This is the 4-pin ATX +12V Power Connector not the hard drive
connectors. I'm assuming the PCI bus gets power from the 24 pin power
connector.


I'm just trying to localize the problem so I can swap something out. I
was told it was probably a PSU problem but that doesn't seem likely in
my experience.
 
It's a Dell sc420 server. It's run good for a year now. Suddenly it
This is the 4-pin ATX +12V Power Connector not the hard drive
connectors. I'm assuming the PCI bus gets power from the 24 pin power
connector.
Click to expand...

If the pin is making poor contact, it would draw more power and scorch the
connector. High resistance connections draw more amps.
 
If the pin is making poor contact, it would draw more power and scorch the
connector. High resistance connections draw more amps.
Click to expand...


As important would be that this resistance, or arching,
itself creates heat that makes the connection even worse and
eventually gets hot enough to char plastic... if the system
manages to keep running in that state.

Given good, tiny tools one can attempt to clean off the
power supply plug or motherboard mating socket but if it
gets bad enough then either the physical connectors will
have to be replaced, or entire component (board and/or PSU)
replaced.

This is assuming there is no other problem causing excessive
current consumption, like shorting capacitors, but if the
consumption had been extreme the PSU should have shut off,
or at the very least this would be revealed by checking the
voltages (but in particular on that motherboard connector,
not by checking some other point in the system, not a drive
plug/etc.
 
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