Jake-S@cup.portal.com (Jake G Schwartz) (01/25/91)
With regard to concerns about CMT RAM cards, apparently EduCalc has communicated with CMT and the policies on the RAM cards are changing. There was originally a 90-day warranty on the cards, and apparently they have decided to match HP's one-year warranty. In addition, it turns out that the HP48 inded *can* detect a low battery in the CMT card, however it will not detect a card with the battery MISSING altogether. This is not usually a problem, I would think. The battery drain in the CMT card is more than two orders of magnitude lower than the HP card with the HP48 turned on, and they're expecting battery life to be atleast two years, and probably a lot more. Thanks to the folks at EduCalc for communicating their concerns (and in turn eventually ours) to CMT so these problems could be resolved quickly. Jake Schwartz
d88joave@IDA.LiU.SE (Joakim A Verona) (01/26/91)
I would like to know how the price of this CMT-card compares with the HP 128k card. Is it any cheaper? If so, how much? -- ============================================================================== ! Joakim Verona LiTH ! Snail: soergaardsgatan 11 ! Email: ! ! Voice: 013/178107 ! 58239 Linkoeping ! d88joave@kolix.ida.liu.se ! ==============================================================================
bill@flutter.tv.tek.com (William K. McFadden) (01/26/91)
So, does anybody actually have one of these beasties? I've been
thinking of getting one, but I'd rather not be a guinea pig. (Not that
I'd want anyone else to be a guinea pig, either. Some are just more
daring.)
HP went to great lengths to explain how the cards were expensive
because they used selected rams that could run on low voltage, etc. Is
the CMT card as robust as HP implies it needs to be?
--
Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077
bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill
Phone: (503) 627-6920 "SCUD: Shoots Crooked, Usually Destroyed"frechett@spot.Colorado.EDU (-=Runaway Daemon=-) (01/28/91)
In article <9958@orca.wv.tek.com> bill@flutter.tv.tek.com (William K. McFadden) writes:
=+So, does anybody actually have one of these beasties? I've been
I do, I do. And judging by the backorders that Educalc had when I went to
order mine, I would say that at LEAST another 150 people have them too.
I suspect that it is much more.
=+thinking of getting one, but I'd rather not be a guinea pig. (Not that
=+I'd want anyone else to be a guinea pig, either. Some are just more
=+daring.)
Little to do with daring and everything to do with price..
=+
=+HP went to great lengths to explain how the cards were expensive
=+because they used selected rams that could run on low voltage, etc. Is
=+the CMT card as robust as HP implies it needs to be?
From what I have heard, the CMT cards will run on less juice for a longer time.
Apparently the big deal was over, whether the hp48 could detect a low battery
condition as it does with the HP cards. I don't see that it is a factor at
all. Barring emergencies, my card will never leave the calculator long enough
to even start drawing power from the Card's battery. They say that the card
battery should hold it up for something like 2 years.. I sure as hell won't
ever have my card out for 2 years.. ;)
As for HP's lengthy claims, I read them too and I don't think I have
heard from anyone saying, that YES they figured that was about right from their
own experience in the electronics industry. In fact, most people who know
anything about electronics are saying that the HP cards ARE expensive to make
but not THAT expensive. I suspect that what you are seeing is.
CMT 128K SRAM = HP 128K SRAM - HP logo
or should that be
HP 128K SRAM
HP logo
-
CMT 128K SRAM
STO
Whatever.. I woulndn't worry about it.. I have had no problems with my card.
Tonight I just archived my calculator. Can you believe 860 Kermit packets..
About 60K.. I love my card.. ;)
=+--
=+Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077
=+bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill
=+Phone: (503) 627-6920 "SCUD: Shoots Crooked, Usually Destroyed"
ian
--
-=Runaway Daemon=-akcs.davemarsh@hpcvbbs.UUCP (DAVID J. MARSH) (01/29/91)
Incidentally, folks, I have recently heard from a veeeery reliable source
that HP may say something about the CMT cards voiding the warranty on
your 48! This seems to have to do with the physical tolerances of the
card itself, rather than any electronic condition. I recently borrowed
one of these cards from Educalc, and I found it to fit quite snugly in
either of the port sockets. The hullaballoo seems to be that this
snugness (caused by the card being thicker than HP standard) may bend the
contacts in the port connectors, eventually causing them to lose contact
with the real world, as it were. Anyway, what it boils down to is the
same old caveat emptor stuff. Personally, I really prefer the quality of
the 'true' HP cards ( I have 5 of them between two 48s ).
Dave Marsharc@dde.uucp (Arne Christensen) (01/30/91)
OK - I am the one who opened this discussion, and I want to say "thank you" to everybody who has helped provide details on this card. I got my card a few days ago (I was too late telling EduCalc to hold it back; it had been sent). After listening to the advice of a couple of netters I opened the package to try out the card (EduCalc generously permitted this). Most of the information I've got has already been reported by Jake Schwartz, but I want to add: There seems to be NO problem with the switch-off voltage (which was the reason HP did some special card design, according to a HP engineer here on this very newsgroup several months ago). The problem was stated something like this: "When the HP48 battery voltage goes low, standard Epson cards may shut off BEFORE the HP48 does. This causes the input pins on the card to be grounded (for protection of the card), which may in turn cause excessive current to be drawn through the card drivers in the 48, possibly causing them to break. Besides that, this means that the card will stop working when the HP48 batteries run low." A hardware engineer friend of mine (he has a 48 too :-)) made a test which showed that the CMT card does NOT shut off this way - it simply never grounds the input pins! (This same holds true for the Eq. Lib. card from HP, by the way). (By the way, a similar test of a standard Epson card shows that the problem stated by HP may in fact be real - I wouldn't take the chance and put an Epson card in my 48.) So the CMT card seems not to pose any danger to the HP48. But! not grounding the input pins makes the card more sensitive to static electricity; which is worsened by the fact that the CMT card lacks the "shutter" (what would you native English-speaking folks call that?) which, on the HP (and Epson) cards hides the contacts when the card is removed from the HP48. This is why CMT provides a bag made of anti-static plastic and recommend that the card is kept in this bag when not in the 48. Further, CMT says that the card should not be plugged and unplugged unnecessarily as this causes too much wear on the contacts. They seem to be of a lower quality than HP's (again according to my hardware engineer friend). It seems that the card has been designed mostly as a RAM extension, not for use as an exchange medium. But of course, at $150, the good news is that it's 45 dollars less than the HP RAM card (EduCalc prices). Also, the CMT card comes with a statement that the card is provided on an "as is" basis, with no promises as to the "quality and performance" (even thought there is a warranty on the card). I guess the reason for this is the American interpretation of "liability" - it certainly looks strange to Danish eyes! By the way (especially for non-Americans): I recommend EduCalc for their service; I was a bit hesitant about bying mail-order from a place that far away, considering the difficulty you might have if things started to go wrong. But this has been a very good experience. ---- Arne Christensen, Dansk Data Elektronik A/S, Herlev, Denmark. Email: arc@dde.dk or ...!uunet!mcsun!dkuug!dde!arc
sburke@jarthur.Claremont.EDU (Scott Burke) (01/30/91)
I can vouch that putting a standard Epson card into a 48SX is a crap-shoot. Moreover, it is calculator-dependent, in that it will work with some 48s but not with others. And for those 48s that _do_ work with the standard Epson cards, if their batteries get low, they join the ranks of the 48s which _don't_ accept the Epson cards. So what, you ask? Well, the typical behavior of a 48 which doesn't like Epson cards is to click and whirr and put blue goo all over the screen, then to ignore all key presses (including ON-C and ON-A-F) until the card is removed and (sometimes necessary) the foot peeled off and the zappo button pushed with a paper clip. Needless to say, most data cannot survive such a process... :-( In fact, the behavior reminds me of the time I dropped my 48 into a sink full of water... :-O So, in summary, Epson cards sometimes work, but their voltage requirements (as explained in an earlier post) have an unpredictable behavior. Scott sburke@jarthur.claremont.edu
akcs.scotty@hpcvbbs.UUCP (SCOTTY THOMPSON) (02/03/91)
Speaking of CMT, I've been debating on getting one for what seems pennies, now, cheaper. However, since HP is replacing my calculator for FREE, and we all have read the warranty that says that they don't have to do anything of the sort, I'm going to buy another HP card as soon as I get my roommate back <grin>. In HP's two volume manual, it also states that the cards will last 1-5 years, depending on the use. I read somewhere on here that stated the CMT card would last two. So far, I've had my battery in mine for almost a year, and I don't mind a bit being cautious and replacing it every year, anyway. Besides, can $0.99 really mean THAT much? Scotty.
akcs.gak@hpcvbbs.UUCP (Eric Gakstatter) (02/20/91)
In response to inquiries about CMT cards for the HP-48, CMT has released the following information pertaining to the power consumption and low-bat characteristics: The SRAM cards have two power sources. The first of these is the battery that is installed in the card. The currents drawn from this battery are shown in Table 1. The other source of power is from the HP-48SX battery when the card is installed in the 48. The currents from this are shown in Table 2. TABLE 1 Card battery current of the HP 128K SRAM card versus the CMT 128K RAM card removed from the HP-48SX. Switch position is indicated as "READ" or "READ/WRITE". CARD READ CURRENT READ/WRITE CURRENT CMT 128K SRAM 0.2876 microamps 0.3003 microamps HP 128K SRAM 1.649 microamps 1.676 microamps TABLE 2 Current draw of the memory cards with 4.4 volts applied to the card and all address and control lines held at ground. This is close to the current draws that occurs when the card is installed in a HP-48 that is turned on. CARD READ/WRITE CURRENT CMT 128K SRAM 2.0 microamps HP 128K SRAM 845.0 microamps Assuming that the card is sitting on the shelf, Table 1 would be the current draw that is applicable. The batteries that are used in the card are 75 mA-hour batteries. Using this, the expected life of the battery in the two different cards is: CMT 128K SRAM -> 249,750 hours -> 28 years HP 128K SRAM -> 44,749 hours -> 5 years This isn't realistic because the lithium batteries decay by themselves in about 5 years. However, it does show that CMT's card battery will definitely last for two years and will probably last for 5 years. The extra battery life makes data stored in a CMT card more secure than the data in the HP card. Table 2 shows that the CMT card draws significantly less operating current than the HP card. This will result in a longer HP-48SX battery life. The HP-48SX low battery indicator works with the CMT cards if a battery is installed. Without a battery installed, the low battery indicator does not work. This is a side effect of designing the card for low power usage. We felt that the decrease in power usage was well worth the trade off. Based on these figures, CMT recommends that the battery in the card gets changed every 2 years. Since the power consumption is so low, CMT also recommends that the battery remain inside the card during storage and shipping. If there are any questions on this matter, please contact: Corvallis Microtechnology, Inc. 413 SW Jefferson Ave. Corvallis, OR 97333 503/752-5456 CMT is a firm believer that the customer should be fully informed of the products they are purchasing.
akcs.gak@hpcvbbs.UUCP (Eric Gakstatter) (02/20/91)
Additionally, CMT has also responded to questions regarding warranty coverage, static protection and mechanical fit. Warranty coverage. All CMT cards for the HP-48SX purchased will have a one year warranty as of 2/20/91. For those concerned about CMT's liability statement, it is a standard statement that protects CMT from incurring liability due to malfunction. For example, if you are using the HP-48SX with a CMT RAM card to store REALLY important data and that data is lost for some reason, CMT is not liable for the cost of recovering the data, etc. What the CMT warranty covers is the card itself. If the card malfunctions, CMT will repair or replace the card. Static charge and mechanical fit. Yes, CMT cards fit more tightly, but this will not cause damage to the HP-48SX connector. The connector in the HP-48SX is designed with plastic bars between each connecting spring so that the springs can not be depressed far enough to cause any damage. If the card is too thick, it won't fit the connector. I would try to illustrate in this message with ASCII graphics, but this editor would send me to my grave. If you are interested in a simple graphic of this, dial up the CMT BBS at 503/758-1419. CMT uses the same connector as HP does for its card tester and it has had hundreds of cards inserted without a single failure. All of the 48's used in testing and development have had hundreds of cards installed and removed without a problem. CMT has tested individual cards for over 1,000 installations with no failure that wasn't cured by cleaning the contacts with a cotton swab moistened(not soaked) with isopropyl alcohol. However, CMT does recommend that users minimize the number of insertions/removals. This applies to all connectors of this type, not just CMT's. For static charge protection, the CMT card uses tranzorbs. A tranzorb is a high speed transient absorber that is used to help protect the card's circuitry from transient voltage spikes. The shutter is patented by EPSON (I believe) so CMT chose to use tranzorbs for ESD protection. Transzorbs have proved to be very effective. CMT believes they have done their homework on these matters. They have produced and tested 1,000's of cards and not experienced an ESD or mechanical problem. As you may know CMT is not new to this kind of technology. They have produced reliable modules for the HP-41, 71 & 75. CMT does recommend that when the card is not in the HP-48SX that you store the card in its ESD protection bag and that you keep your fingers away from the gold connectors. This is really no different than the normal precautions that you would take with any circuit board. CMT feels that the card connectors and the CMT memory cards are quality products that should bring you years of use.