Listers, I bought two PWT's from Trem a couple of years ago and check one off against the other. The battries are expensive $3.50 each and wach PWT takes 4 small micro units.
I bought battries recently from Radio Shack (#23-105 -- 1.5v Watch & Calculator) -- I unpacked the first from its sealed sales card holder and measured less Milli-Amps than the old ones -- in other words they were old and had no "useby date" so beware!! The battery manufacturers have a free ride -- they never have to really guarantee their products will work for any period of time etc. Yes! Some do have use-by dates. Now there's a "Consumer Issue" for someone looking to become famous!! Douglas H ---- Ode Coyote <[email protected]> wrote: > > The calibration solution I got from Hanna was 50% off spec. Plenty of > denial, no refunds. > I learned a lot by deduction and it took about a month to figure it all out. > The calibration instructions were far from enlightening and didn't > mention what temperature compensation was all about. > Hanna Tech was like "You're too stupid to ask questions, so stop it" [If > we tell you the real story, you'll see how misleading our ad copy > is...defend the product at all costs. ] > > Fortunately I had 2 PWTs to make comparisons by and make deductions from. > > Ode > > At 10:53 AM 7/9/2006 -0600, you wrote: > > >Hi Mike, > > I haven't worried about calibration since the first couple of months I > > owned my PWT. It has remained consistent with itself, and the measurment > > of uS of an immediately finished batch of CS in my Silverpuppy never > > varies more than fraction. > > A meter that isn't too far off, that gives consistent readings of both > > my DW and the finished CS is more important than that it read an exactly > > accurate uS. Hope that makes sense? I can tell immediately if anything is > > different in the DW or the CS, and I think that consistency is what is > > important. > > > > I believe Ode some years back had a similar experience to what you > > described your friend had with two PWTs that gave very different readings. > >sol > > > >Mike Monett wrote: > > > >>I have a Hanna PWT but the COM100 is next on my > >>shopping list. I really like the temperature display, and I understand from > >>David that the probe is a bit smaller than the Hanna which will make it > >>easier to get readings from a bit of cs in a shot glass prior to sublingual > >>absorption. > >> > >>I should also mention that my Hanna arrived several years ago in perfect > >>calibration, and has held the original calibration extremely well. I have > >>verified it numerous times with precision measurements using the Faraday > >>calculation, and it has always agreed within 1uS up to about 15uS. The > >>readings tend to depart around there due to AgOH formation. So I am > >>confident my unit is functioning well. > >> > >>My faith in Hanna plummeted recently when I recommended a friend get one. > >>She got two, with the calibration solution. When she brought them over to > >>compare calibration with mine, we discovered that one unit was so far out > >>of calibration that the adjustment screw could not bring it into > >>calibration. > >> > >>The second unit was fine, but it was out of calibration. We discovered her > >>calibration solution read high, about 96uS. So I recommended she send them > >>back and get a refund. > >> > >>It is very difficult to recommend what to do to verify the manufacturer's > >>products in a case like this. If you can do the Faraday calculation, it can > >>help up to about 15uS. The salt test is useful, but it takes practise to > >>judge the readings, and they won't be closer than about 5uS. So it can only > >>catch gross calibration errors. Diluting a saturated salt solution takes > >>some skill, and the resulting solution may not be very stable. It can also > >>become contaminated from the container the solution is stored in. > >> > > > > > >-- > >The Silver List is a moderated forum for discussing Colloidal Silver. > > > >Instructions for unsubscribing are posted at: http://silverlist.org > > > >To post, address your message to: [email protected] > > > >Address Off-Topic messages to: [email protected] > > > >The Silver List and Off Topic List archives are currently down... > > > >List maintainer: Mike Devour <[email protected]> > > > > > > > > > > > >-- > >No virus found in this incoming message. > >Checked by AVG Anti-Virus. > >Version: 7.1.394 / Virus Database: 268.9.10/383 - Release Date: 7/7/2006 > > > > -- > No virus found in this outgoing message. > Checked by AVG Anti-Virus. > Version: 7.1.394 / Virus Database: 268.9.10/383 - Release Date: 7/7/2006 > >
