[iyonix-support] Re: Dead PSU

On 12 Aug, Frank de Bruijn wrote in message
  <4f114b7da3frank@xxxxxxxxxx>:

> In article <b0533a114f.steve@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
>    Steve Fryatt <lists@xxxxxxxxxxxxxxxxxx> wrote:
> 
> > If you've had the Iyonix for "years",
> 
> Since July 2003.

Ditto.
 
> > then it's likely that the PSU has just reached the end of its natural
> > life.  They are usually designed for four to five years' life;
> 
> Is that related to what's considered the normal lifespan of a PC these
> days?

Partly.  It's also what is achievable given the constraints of
performance, space and cost.

> > some will fail sooner (but hopefully not in warranty!), some later.
> > The variation is down to factors such as manufacturing tolerances on
> > components.
> 
> Well, then either the standards must have dropped or I've just been very
> lucky with the PSU in my RiscPC. I bought that machine in October 1994
> and it's even been switched on 24/7 since early 1998.

You may have been lucky.  My first RiscPC PSU failed less than a year
after purchase in 1994.  Acorn replaced it under warranty.

Others have commented on relative cost between a RiscPC's PSU and a modern
ATX model.  The design is also a factor: the box is similar size, but the
ATX PSU is producing over twice the power output.  It's been a while since
I opened up my RiscPC's PSU, but the last time I did, ISTR it contained
components significantly bigger than I'd have used in a 100W design. 
These days, there's a demand to fit ever more in the same space, and
something has to give.  Modern PSUs run hotter, which reduces the life
significantly.

> I wanted the Iyonix to replace that RiscPC. Some issues with getting
> some 26-bit software updated got in the way, so I used the Iyonix far
> less than I had expected (and it had only been running 24/7 for about a
> month when the PSU failed). And now *it* has broken down! And the RiscPC
> is still running 24/7 without a problem.

So, you've been unlucky.  Sorry if that sounds harsh, but the PSU is at
the mercy of the most unpredictable and unreliable component used in
electronics.  Estimating lifetime is hard, and the figures are only going
to be an average.  50% of the units will fail before then; 50% will last
longer.

Out of interest, is the machine left with mains applied when off?  If so,
it /has/ effectively been on 24/7 as the Aux supply will have been on for
all that time.  Since the Aux supply powers the rest of the PSU's control
circuits, if that dies, the whole lot is useless even if the main bits
have only been on occasionally and still have years of life left.
 
> So I'm going to have to replace a significant part of the machine bought
> as a replacement for a much older one, which is still running fine.
> 
> Now call me silly, but *THAT* I find annoying.

To be honest, I wouldn't call the PSU a significant part -- certainly not
cost-wise.  It's certainly vital to the operation of the system as a
whole, but replacement is quick and simple.
 
> > It would be nice for them to last longer, but usually consumers aren't
> > willing to pay for that.
> 
> Would buying a not-so-cheap replacement be advisable? Or don't they
> generally have more reliable components and such than the cheap ones?

The really cheap ones tend to die in twelve months.  HEC aren't a brand
I've come across aside from the Iyonix, but I have a suspicion that
they're not that shoddy.

-- 
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/

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