Hi !

sorry..i haven't being checking the ML for a while.
your problem is rather typical and (as others has already said) it's very 
likely due to the power supply.

checking power availability is first: with every mobo you find a manual where 
you find the minimum required power rating (nowadays PCs require at least 
250Watts on ATX mobo, CRT excluded)

if it's enough and if the system at least tries to boot, you can be sure you 
have +5 and +12 on the line...so, no need to check with a voltmeter.

however, those line could be the weak point. the fact is that every mobo 
requires a DC voltage, but no ps is able to provide it exactly.
from the plug in the wall you get an AC at 50Hz , 230Volts (in Europe) or 125V 
(or so.., in USA) and your PS job is to convert this alternate current in a 
DC one, but there will always be a residual AC component over the DC output.
For those unaccustomed to electrical stuff, there are two pictures attached to 
this post.
Now, if for ANY reason, your ps started giving out a DC voltage with a strong 
superimposed oscillation, then you mobo and hw are going to fail in a rather 
unpredictable way !!!!
Unfortunately, checking with a voltmeter, you'll always read 5V and/or 12V 
because that simple instrument is NOT able (in its basic form of usage) to 
show you the AC components.
For those interested, you should check with an oscilloscope ( AC-coupling 
mode, detecting peak voltage) or a spectrum analyzer.

Example of reason why a fuxxing ps might leave unattenuated AC components:
- lightenings
- age
- nuclear explosions
- e-granade bombing
- electricity-society people at work in your last-mile net
- Murphy's Law

Finally, my suggestion is to change your ps (repairing is rather not worth tha 
cosi, if it's not self-done).

Just to let all of this be more useful for everyone, the most common cause of 
wierd hardware behaviour is the power supply ! So, check it out !!

nice hw hacking to everyone,

 R#

<<attachment: ac.png>>

<<attachment: actual_dc.png>>

--
[EMAIL PROTECTED] mailing list

Reply via email to