[OT] newbuilt computer won't start

[Jeffrey F. Bloss]

Mikael Backman wrote:

> Thank you for your reply.. I unplugged everything and check for bent 
> pins etc.. Things seemed ok..  

Double check again. :) I've built machines literally numbering in the
thousands over the years, and I've repeated stupid mistakes hundreds of
times as a result. A reversed or misaligned connector has sent me into
a head scratching session more times than I care to admit. Aside from
hardware failures, they're one of the most common causes of a machine
just "not booting"

If your motherboard has jumpers for clock/bus speed and CPU voltages go
over those again too...

> Then I plugged in power to the mobo
> and cpu, the cpu-fan  and the power swicht . Nothing else but still
> no beeps at all (I connected headphones to the line-out of the
> internal adio card)

The on board sound card may not work this way. :(

There should be a connector on the motherboard for a PC speaker. If
not you may never hear POST errors. Check the motherboard manual if
you have it handy. It should point you to the connector. Or look
for two pins with SPK, SPKR, or such silk screened nearby. Quite often
they'll be in the same place or bank as connections for power switches,
LEDs, etc. 

If you do find the connector and don't have a PC speaker handy, most any
small, unpowered speaker will do. Cut and strip the wires of an old set
of junk computer speakers everyone has laying around, and carefully
attach them with small alligator clips or something. Use your
imagination. ;)

If you do happen to have a board with absolutely no way to hear POST
errors then you're stuck with video (some are designed that way). Make
absolutely sure your monitor works by testing it on another system
first.

Strip everything you can out of the box, disconnect everything you
possibly can and still power up the board, connect a monitor, and start
the "testing cycle". Power up, look for errors, add a component,
repeat. Some boards won't boot at all without RAM, so test first
without it, then with it. Don't even hook up fans at first in fact. It
won't kill the CPU to run for a few seconds without cooling. The idea
is to eliminate *every possible* point of failure, hopefully see some
sign of life, then start adding things back into the equation until it
dies again.

If you don't get some sort of response with just power, or power and
a minimum of RAM, you're probably looking at a bad motherboard or power
supply. You may want to pull the motherboard out of the case and run
power to it while unmounted, sitting on a non-conductive surface of
course. Sometimes a cold solder joint can "open up" under the stress of
being screwed down. While you have it out of the case, give it a
careful examination for soldered connections that don't look right,
cracks, and the always dreaded "burn spot". The tiniest defect in the
wrong place can be fatal, so be thorough. And cold solder joints are
pretty easy to fix if you're brave enough to go after multi-layer
circuit boards with a soldering iron. ;)

If you have another power supply, test the motherboard with that. Even
if you just (carefully) disconnect one in another case and (carefully)
run the connectors to your motherboard while it's outside its own case.

Again, the key is methodically eliminating possibilities until you're
left the component causing the problem, and swapping in known good
components where necessary. That's the "bread and butter" of hardware
troubleshooting. 

-- 
     _?_      Outside of a dog, a book is a man's best friend.
    (o o)         Inside of a dog, it's too dark to read.
-oOO-(_)--OOo------------------------------[ Groucho Marx ]---
                    http://wrench.homelinux.net/~jeff/
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