SUUNTO Battery Replacement?

H. Huntzinger <recscuba@huntzinger.com> wrote:

> One thing that concerns me about user-replacable battery based dive
> computers is ... when was the last time you really were sure what its
> calibration was?

Remember that for depth gauges, it's not really the "absolute" accuracy
per se, it is the repeatability. OK, I know that applied more for plant
instrumentation, but most analog scuba equipment falls into the +/-5% or
even +/-10% FS range, with pressure gauges varying more around 1-3% FS
with their more accurate pressure transducers.

That's why it is always an interesting experiment (such as on the Deep
dive of the PADI Adventures in Diving/ AOW course or similar) to compare
instruments with your buddy (like in Rich's followup post). During the
last trial with my buddy, the variation on the instruments was about
+/-0.5 to 1 meter at 30 meters depth. This was for the electronic
gauges, a Citizen HyperAqualand, a Genesis Resource computer (my stuff),
a Suunto Spyder (buddy). For my analog depth gauge, there was about a 2
meter difference.

I'd be interested in hearing from someone how dive computers are
calibrated. Is there a pot on the board, or ???

--
Matt
matt@gol.com

"Matthew Endo" <matt@gol.com> wrote in message
news:1fzilsy.covwiy1w8fp8gN@yahoobb219000172016.bb tec.net...

> The point is that if the tech forgets to put the O-ring back and floods
> it during the pressure test, he has to give you a new one. If you screw
> up and flood it, you get an expensive paperweight.

Naw, they make great reactive targets, 'specially the oil filled ones...

Scott

Scott <scott@selchiedotcom.com> wrote:

> Naw, they make great reactive targets, 'specially the oil filled ones...

I like bowling pins, and aiming for the head.

--
Matt
matt@gol.com

"Matthew Endo" <matt@gol.com> wrote in message
news:1fzio2o.1sj7mz91eq5mobN@yahoobb219000172016.b btec.net...

> I like bowling pins, and aiming for the head.

Yep, and they are almost as expensive as computers...

Do they let you guys run bowling pins with 1911's in Japan?

Scott

Scott <scott@selchiedotcom.com> wrote:

> Do they let you guys run bowling pins with 1911's in Japan?

I'm talking about the States. Remember I'm originally from Kalifornia.

--
Matt
matt@gol.com

"Matthew Endo" <matt@gol.com> wrote in message
news:1fzioij.1pczqc3lbx490N@yahoobb219000172016.bb tec.net...
> Scott <scott@selchiedotcom.com> wrote:
>
> > Do they let you guys run bowling pins with 1911's in Japan?
>
> I'm talking about the States. Remember I'm originally from Kalifornia.

Juss' messin wicha...

Matthew Endo wrote:
>
> Rich Lockyer <rlockyer@linkline.DONTSPAMME.com> wrote:
>
> > I can drop it in the pool for a few hours to make sure that it's
> > basically solid. If it's going to leak at 100ft, it'll leak at 10ft
> > given enough time.
>
> The point is that if the tech forgets to put the O-ring back and floods
> it during the pressure test, he has to give you a new one. If you screw
> up and flood it, you get an expensive paperweight.
>
> --
> Matt
> matt@gol.com

Or it just gets a load of N2 gas. There is more than one way to do a
pressure calibration.

west

In article <3F370B31.138FD7D0@hal-pc.org>, west <westd@hal-pc.org>
wrote:

€Matthew Endo wrote:
€>
€> Rich Lockyer <rlockyer@linkline.DONTSPAMME.com> wrote:
€>
€> > I can drop it in the pool for a few hours to make sure that it's
€> > basically solid. If it's going to leak at 100ft, it'll leak at 10ft
€> > given enough time.
€>
€> The point is that if the tech forgets to put the O-ring back and floods
€> it during the pressure test, he has to give you a new one. If you screw
€> up and flood it, you get an expensive paperweight.
€>
€> --
€> Matt
€> matt@gol.com
€
€ Or it just gets a load of N2 gas. There is more than one way to do a
€pressure calibration.
€
€ west

True, but what you've just described would be an accuracy check, not a
leak test. When you send send the computer back to Suunto (Seaquest)
for a battery replacement, their pressure test includes a leak test in
water.

And Rick, your assumption that a test at 10 feet for 100 hours is the
same as 100 feet for 10 hours is invalid. While it's *likely* that most
problems are going to cause leaks at 1/3 atm, it's also possible for
there to be very minor defects in the o-ring or seating surfaces that
might not leak until the pressure differential gets to 2 atm or above.
Unless you're comfortable with changing batteries and o-rings yourself,
I like the advice given above - letting the factory do it gives them
the responsibility for doing it right.

Having said all that, it's not really rocket science. I work with high
vacuum and UHV equipment, and in the UHV world, cleanliness is next to
godliness when it comes to sealing surfaces. A 1 micron sized particle
of dust can ruin your day when it gets into your process, so we get
kind of anal about cleaning our sealing surfaces. If you take the same
attitude towards inspecting and cleaning the o-ring and sealing
surfaces, and remember that the purpose of o-ring grease is to allow
the o-ring material to "smush" (a nice technical term against the
sealing surface with as little of the grease itself getting in the way,
then you won't have any problems re-sealing your computer against the
any pressure it was designed to handle. Access to a good low-power
microscope is also helpful.

Alan

On Mon, 11 Aug 2003 03:59:56 GMT, Alan Street <alan@nonono_irsi.com>
wrote:

>Unless you're comfortable with changing batteries and o-rings yourself,
>I like the advice given above - letting the factory do it gives them
>the responsibility for doing it right.

The O-ring on my scooter and video housings make me more nervous than
the one on my Vyper.

Come to think of it, they'd be more expensive mistakes too.

>the o-ring material to "smush" (a nice technical term against the
>sealing surface with as little of the grease itself getting in the way,

Yup.
Unless it's an Uwatec Neverlost :)



--- Rich
http://richlockyer.tripod.com/

matt@gol.com (Matthew Endo) wrote:

> H. Huntzinger <recscuba@huntzinger.com> wrote:
>
> > One thing that concerns me about user-replacable battery based dive
> > computers is ... when was the last time you really were sure what its
> > calibration was?
>
> Remember that for depth gauges, it's not really the "absolute" accuracy
> per se, it is the repeatability.


Sure, although the 'absolute' accuracy is imporant because it is assumed
within our DCS model. If the gage is underestimating and we start to
push no-stop limits and the like, we will eat into our DCS safety
margins. This becomes more important on dive computers than tables, as
we don't have the same "round up" conservatisms.


> That's why it is always an interesting experiment (such as on the Deep
> dive of the PADI Adventures in Diving/ AOW course or similar) to compare
> instruments with your buddy (like in Rich's followup post). During the
> last trial with my buddy, the variation on the instruments was about
> +/-0.5 to 1 meter at 30 meters depth. This was for the electronic
> gauges, a Citizen HyperAqualand, a Genesis Resource computer (my stuff),
> a Suunto Spyder (buddy). For my analog depth gauge, there was about a 2
> meter difference.

So there's a 1.5-6ft variance between gages that were last calibrated at
some unknown time. FWIW, I do this too, and have generally been
surprised that depth gages match up as well as they do. Nevertheless, I
have seen ~5ft depth variances on ~60ft dives, which is pushing 10%.
I've also seen compasses with 30 degrees of error on reprocity.


> I'd be interested in hearing from someone how dive computers are
> calibrated. Is there a pot on the board, or ???

There has to be a A/D coverter someplace, with a calibration value. Its
probably no longer a pot, but a digitally programmed value, these days.


-hh