Re: 2 Fried G210's in a single day :-(

Hmmmm, Well... I was pretty happy with Mariss until he announced to
the world that me frying my drives puts me in the .05% bracket of
human capability :-/ (or is that 2 drives at .025%) !!!!

(sigh)

Send some more Mariss, I have my Mig welder all powered up and ready
to go as the supply!!

Sean

--- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> Hi,
>
> I've been following this thread with attention, so before replying
I
> decided to research my "deep-fried gecko" database to see what
light
> it would shed. I looked up the results for the last 12 months,
April
> 2001 to April 2002.
>
> In that time period 6,813 geckos shipped out and 129 came back
fried.
> That is an unadjusted failure rate of about 1.9%, which is not too
> good until it is analyzed further.
>
> Every returned drive is tested and the cause of the failure is
> entered into a database. This discards about 110 drives because
> typically 1/2 of the drives I see coming back have no discoverable
> problem. Of the 129 "fried" ones, every effort is made to
determine
> the precipitating event that led to failure.
>
> Of the 129 that were actually fried, 69 were determined to be user
> induced failures. Some were truly spectacular, such as the 2 that
had
> 115VAC and the one that had 230VAC applied to the power supply
inputs.
>
> As probably everyone knows by now, we have a "one time stuff
happens"
> deal. This means a drive is replaced one time, no charge, no
matter
> the reason. All that is required is a full confession as to what
> happened along with the dead drive. This helps me to see what the
> common mistakes are.
>
> Of the remaining 60 drives, it was not possible to determine with
> certainty what precipitated the failure with 38 of them. Either
they
> were too badly damaged to do a forensic examination or the failure
> was of such a nature that it could not conclusively proved to be
> caused by the user.
>
> That leaves 22 drives where the fault was entirely ours. Here
there
> were logic ICs that got bored doing Boolean algebra, capacitors
that
> wanted to be short circuits and resistors that felt infinite ohms
> should be their existential goal. Throw in a cracked PCB trace
that
> only reveals itself with board flexure, a solder-paste joint that
> failed to wet an IC pin and cold wave-soldered joint because
> someone's guacamole got on the board. That pretty much runs the
gamut
> for these 22 failures.
>
> I then compared these failure rates against our OEM accounts
versus
> individual end-users. Our mix is about 70% OEM versus 30%
> individuals. OEM by our definition is someone that uses more than
100
> drives a year and incorporates them into a product they
manufacture.
> Some numbers shifted dramatically here.
>
> User induced or undeterminable failures were 19* drives out of
4,680
> OEM units shipped, or 0.4%. Non-user induced failures (our fault)
> were 12 units, for a failure rate of 0.25%. This is a much more
> tolerable number.
>
> Mariss
>
>
> *The user-induced failure of 19 drives was skewed by one OEM
customer
> that had a bad (shorted turn) motor in their incoming inspection
test
> stand. The receiving inspector went thru 8 drives before someone
> thought there might be a problem here. They sent the motor to me
as a
> trophy after things got straightened out. To my knowledge, it has
> killed more geckos than any other motor I know of.
>
>
> --- In CAD_CAM_EDM_DRO@y..., beer@s... wrote:
> > On 7 May, CAD_CAM_EDM_DRO@y... wrote:
> >
> > > All the problems I had appeared to be due to false contacts on
> motor
> > > leads (two times) or a spike on the motor connection when
> plugging
> > > the fuse into its socket (the caps were still loaded ... ).
> >
> > > I'm a product designer and in my job I know an important rule:
> every
> > > product should be designed with a reasonable fault tolerance.
> >
> >
> > There are limits to what constitutes "reasonable". Certainly,
> asking
> > the Gecko to survive a roaring fire would not be considered
> reasonable
> > by most people. Asking the Gecko to survive being run over by a
> > bulldozer would also not meet most people's reasonable test.
> >
> > Well, the electrical nastiness you've imposed ( most likely as a
> result
> > of arcing ) would very likely be placed in the same class as the
> above
> > examples by many electronics designers.
> >
> > It may seem like a small thing to you, but to others it's a
really
> big
> > thing.
> >
> > For myself, being basically poor, I'd rather have the most
stripped
> down
> > ( and therefore lowest cost ) unit possible and then simply be
VERY
> > careful.
> >
> > When I feel the need for insurance, I buy a completed finished
> product
> > with a warranty.
> >
> > Alan
> >
> >
> > --
> >
> > Alan Rothenbush | The Spartans do not ask the
number
> of the
> > Academic Computing Services | enemy, only where they are.
> > Simon Fraser University |
> > Burnaby, B.C., Canada | Agix of
> Sparta