Quoting Declan Moriarty <junk_mail at iol.ie>:
> Recently, Somebody Somewhere wrote these words
> >
> > So I'm left with the problem of determining if its the CPU or
> > motherboard.
>> Can you get into the bios? Do you see the ramtest? Does the screen
> power on? Have you tried a minimal boot - reset button unplugged,
> 1 small Dimm, 1 Drive, no pci, no usb etc.
no video signal from the machine, even though the graphics card is working. So
basic assumption is that something is failing during POST. All pci cards were
disconnected.
Since my testing was a little haphazard the last time due to time restraints
(needed to get the working machine back together for the family), I plan on
taking out the entire new machine from the case and attempting to start it
outside the case.
> If you can verify it failing POST (i.e. starting POST) it's the
> motherboard - with 90% certainty. If the cpu is dead it does
> nothing. Like if it powers the monitor on, I'll bet on the
> motherboard.
monitor remains on standby even when power is on in the graphics card and the
various fans start and the single hdd spins up.
> Another idea is to 'receive' a signal from it. The amd-64 runs at
> gigahertz. That's divided down all over the place AGP, PCI, IDE,
> etc. Now you can feed in a signal from an aerial into whatever
> receiver you have, as all these things broadcast. A steady whine
> is what as well as the cackle. You can also hear a harmonic of it.
> Get an electrically quiet area, and hold an aerial or rabbit's
> ears about a foot away from the box.
>> You'll get the power supply with a transistor radio on long wave.
> IDE/pci will be at the low channel numbers on a telly (The old
> Band 1 for 405 line transmissions). The higher numbers (over
> channel 21) are uhf, i.e. channels 21-68 at 470-900Mhz You should
> pick up a harmonic of something there Just wavy lines or a buzz on
> the sound.
>> If the above fails....
>> If you can get a multimeter, set the voltmeter for 5V, and measure
> (CAREFULLY) between pins 28 & 14 on the flash (if it's 28 pin) or
> pins 16 & 32 if it's 32 pin for 5V. 14 is the ground, and keep the
> black lead there for further measurements. Take care not to slip
> from pin to pin - that's the way to blow things.
>>> It's numbered this way
>> __ ___
> Pin 1| \_/ | Last pin
> Pin 2| |
> | |
>>> Pin 14 is ground. The falsh, or eprom with bios in it, is usually
> big enough to measure on. Pin 22 (on a 28 pin) or pin 24 (on a 32
> pin) as Address Latch Enable, and that should be clocked regularly
> while the post is running. It will read between 2 and 3 volts if
> clocked. Likewise the pins on both sides of 14 (or 17) are the
> databus, and they should vary. If they don't it inclines me to
> condemn the cpu (60/40)
Didn't think of using a voltmeter, cheers!
> By this stage you'll be so fed up you won't care and will gladly
> pay for a new m/b and cpu :-D.
and if I do it will be a motherboard with the seven segment led's so I know
which component just went toasty. :P
Frustration just isn't the word :(
--
Darragh
"Nothing's foolproof to a sufficently talented fool"
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