[plug] Warning: PC Hardware can catch fire.

[Tony Clark]

Sorry Gavin I think you are speaking through your ar**.


On Friday 09 August 2002 05.37, Gavin Rogers wrote:
> At 22:58 8/08/2002 +0800, you wrote:

>
> I think the power supply in machines we are getting now are complete junk.
> I've had more computer failures due to power supply problems than any other
> fault!

I can't remember the the last time I had a crook PSU.  I can however remember 
bad RAM, MBs x2 in the last 12 months.

>
> Opening up any modern power supply reveals they are very poorly put
> together with hot-melt glue holding everything in place, the fuses are

Hot melt glue is very effective in holding things together, it doesn't look 
pretty but it does a good job.

> soldered to the board and components are chosen that are very close to
> their maximum rating during normal operation (like choosing 250V
> capacitors). All these lead up to a power supply that goes boom! one day...

250V caps are not a problem in most computer PSUs as they use a bridge design 
which means the caps in the bridge are only subject to 1/2 the supply 
voltage.  around 170 - 200 VDC on each cap.

> Also, I'm astonished that computers catch fire like that !! That's what the
> *FUSE* is for. If the fuse didn't blow and continued to function while a
> current high enough to cause fire was being drawn then the power supply has
> a *FAULTY (read ILLEGAL) DESIGN*.

absolute bull.  A 25 watt soldering iron can make things catch fire, I use to 
light my smokes with one.  You talking a 300W PSU, that is a lot of power and 
can easily make things burn without blowing a fuse.  Take a look at ohms law 
for further information.


>
> Putting a surge protector in line will probably help protect the power
> supply from the damage that causes these problems, but there is no excuse
> for a power supply to pass its 240V supply voltage onto its DC side after a
> failure. None at all. Shouldn't happen...

any very rarely does, I've never seen one do it actually, even some of the 
ones I designed...which surprised even me :)

>
> Forget trying to get yourself a year-long uptime :-) Cleaning out the dust
> in your computer (and inside the powersupply if you know what you're doing)
> with a paintbrush every now and again makes it less likely your machine
> will blow up.
Don't do it with the power on :)


tony

off the list for 5 months back for 12 hours now :)
-- 
Contract ASIC and FPGA design.