[Sussex] Fault possibly developing on my PC

[John Crowhurst]

On 15/11/2012 04:22, Paul Willis wrote:
> Read up on ATX here: http://en.wikipedia.org/wiki/ATX and NB section
> on Dell power supplies!  A look at the wire colours should tell you if
> you have a non standard setup. Your power switch clearly does work
> because the system starts to fire up when pressed. The failure to
> latch is between the board and the psu. If you read the wiki you will
> see that you can power up the system by joining the green wire to a
> black one beside it IF you have the standard wiring, otherwise for the
> odd Dell it is the grey one in the corner that needs joining to a
> black to ground it.
>
> At a guess your problem is a leaky capacitor on the mainboard that
> will not hold your power-on switch circuit down to earth until
> something else has charged up to full voltage. Old age death of
> motherboards is usually due to old capacitors breaking down.

When you mentioned the possibility of a leaky capacitor, it reminds me 
of an incident that happened some years back. A capacitor manufacturer 
created a top secret formula for their electrolytic capacitors that 
after the formula was stolen and used to make a large batch of 
capacitors by a rival competitor, it was found that the capacitors were 
prone to leakage and exploding in some circumstances and so they changed 
their formula. However, Dell bought their capacitors from the rival 
competitor and refused to recall their motherboards.

I remember it also happened with the Lithium-ion battery manufacturer 
and several laptops either exploded or burst into flames and the 
manufacturer denied knowledge of that one, only for it to be captured on 
video and uploaded to YouTube for Dell to issue a recall.

Things to take in consideration when replacing Dell parts:
Dell power supplies are not always pin-compatible with generic power 
supplies, the connectors may fit but the motherboard may not power up.
Dell cool their processors with a rear case fan instead of a CPU fan. If 
you plan to change the case, you need a new heatsink and fan.
Also, if you plan to change the motherboard, you may find the plastic 
shroud that draws the air through the rear fan no longer fits, so you 
will probably need a new heatsink and fan.
You can still get new Socket 478 motherboards, the original motherboard 
is a 845 chipset but there is an 865 chipset (like ASRock P4I65G) that 
takes the older DDR memory as in this Dell, giving you SATA-1 and 2xPATA 
with AGP graphics. The 945 chipset (the ASRock P4I945GC) takes DDR2, so 
you'll need to replace the memory, but it offers SATA-2 and 2xPATA with 
PCI and PCI express.

Best,

John