daver@hpcvca.HP.COM (David Rabinowitz) (02/10/89)
>So there I was this morning, sitting in the middle of an exam and I >reach for my 41cv and ack! It does not turn on - a students ultimate >nightmare. What are the symptoms? Have you checked your batteries? First try replacing the batteries. If that doesn't work, try holding the ENTER key while pressing ON; that will get the calculator out of any software lockup condition it may have gotten into (the calculator can get into a software lockup because of electrostatic discharge - ESD can induce signals in some of the wires or PC traces between chips which are indistinguishable from valid logic signals and can force the program to jump into the middle of a 2-word instruction or a ROM table or just a loop which was not initialized in a way that will guarantee exit). If that doesn't work, try holding the <- key while pressing ON. This will clear memory, which will allow the calculator to recover from lockups caused by an inconsistent memory structure which could have been created by ESD and could cause a software loop to never exit. If none of these work, remove anything you have plugged into the calculator and then remove the batteries and hold the ON key down for several minutes to drain the "keep-alive" capacitor (which preserves memory while batteries are being changed). Then replace the batteries and try again. If none of these steps work you'll need service. >Does anyone know if hp still has a mail in repair shop? Can you post >or mail a response? How much does a cv or cx go for these days? I >paid > $200 a couple of years ago for the cv. HP still services all calculators, on a parts-available basis for calculators which have been discontinued more than 5 years ago. Since the 41CV is still being sold it is still being serviced. Your local HP dealer can tell you how to get the calculator repaired. The list price for the 41CV today is $175, though you can get substantial discounts from some mail order shops. >All I really need in a handheld is 1) rpn, and 2) capabilities similar to >the 41cv + math pack offered. What are my choices these days? You might consider the 42S, which has the same user interface as the 41C but more memory and lists for $110, or the 27S, which is also RPN, but has a different user interface for the same price. Both calculators have more memory than a fully-loaded 41CX, but neither supports plug-ins. Alternately, you may want to look at the 28S, which has everything (except plug-ins).
bruce@hpcvra.HP.COM (Bruce Stephens) (02/15/89)
In an earlier reply, Dave Rabinwitz stated the following: >You might consider the 42S, which has the same user interface as the 41C but >more memory and lists for $110, or the 27S, which is also RPN, but has a >different user interface for the same price. Both calculators have more >memory than a fully-loaded 41CX, but neither supports plug-ins. Alternately, >you may want to look at the 28S, which has everything (except plug-ins). The HP27S is NOT an RPN machine. It uses algebraic entry. Also, the HP-42S lists for $120 (not $110 like the HP-27S). -- Bruce Stephens bruce%hp-pcd@hplabs
tim@scsmo1.UUCP (03/02/89)
I have an HP-28C that I like, and highly sugest looking at a HP-28S since I don't think that the 28C is made anymore. The Calculator has some problems. (28C anyway) 1. It has done derivatives wrong. 2. It can symbolicly integrate any polynomial with positive integer exponents. 3. It is hard to do character I/O in a nice way. 4. It has no input other than the Keyboard. 5. It's keyboard has a poor feel to it. 6. The manual is poor. 7. It needs a lot more memory, (hard disk, virtual memory... :-) 8. It will do Degrees and Rads but no Grads. 9. The beeper is anoying Its advantages. 1. It will do almost anything you want a calculator to do. 2. It has a 1 Meg address space. 3. It will do symbolic calculus to a point. 4. Easy to use. (RPN, infix and combination) 5. It will graph. Some solutions to the disadvantages: 1. Don't push it and know derivatives. 2. Do it by hand, its faster and easier. 3. Don't try to write menu type programs (or get a 28S) 4. Hack it to death. 5. Take the keyboard apart and put it back together a little looser. 6. Uh. Write your own? 7. See 4. 8. Is there anyone how uses Grads? 9. Fix it with #5. (take out one of the little springs) So I'm showing the bad points, and not stressing the good, so what I'm not getting paid to sell these things. If you have anyinfo on hacking on these, I'd like to hear from you. (syseval or hardware) -tim@scsmo1.UUCP