Hewlett Packard 49G+ Graphing Calculator Review

Average Reviews:

(More customer reviews)I purchased the HP 49g+ in August of 2004 as a replacement for its predecessor, the HP 49G.In my initial review of the 49g+, I downgraded it from 5 to 3 stars because of problems with keys not registering, and because of the amateurish user documentation.HP made a new firmware release available in May 2005, and it appears that the problems with key presses not registering were largely due to flaws in the way that key events were handled in the software, which evidently have now been fixed, with the possible exception of the function keys along the top row.That would have motivated me to increase my rating, were it not for the problem with the tendency for the keypad to wear out prematurely, which I have recently discovered.The Delete key on my 49g+ broke recently, and HP replaced it with a new unit.When I took the broken unit apart, I wasn't pleased with what I saw.Unless changes have been made to the keyboard design, I can confidently predict that the keyboards on all 49g+ calculators will break long before any external sign of wear, and when this happens, the calculator will become an expensive paper weight.Because I have no reason to expect the keypad design has been changed, I have no choice but to withhold any recommendation for this calculator.This is especially lamentable because if you consider only the remarkable capabilities of the software that runs on this calculator, it would easily garner a 5-star rating.

The user documentation that HP provides is woefully inadequate in numerous areas such as the important Equation Writer application and calculator programmability.The two CAS modes that each influence whether the calculator returns exact, symbolic results or approximate, numeric results, are fundamentally important.Given that these two mode settings are independent binary flags that differ in their esoteric effect, exact descriptions of the effect of each of these modes is fundamentally important.Yet, the descriptions given in the manuals are incorrect and useless.

In order for you to be able to anticipate what the calculator will do in any given scenario, you need to have a meaningful understanding of the rules that govern recursive expression evaluation, which is at the heart of calculator operation.Yet, you cannot find a meaningful discussion of expression evaluation anywhere in the user documentation.Prior to the introduction of the 49g+, you could acquire a meaningful understanding of expression evaluation by reading the manual page for the EVAL command in the 49G reference manual.But HP has since removed that manual from their web site.That not only removed the only accessible explanation of expression evaluation, it removed the only meaningfully complete descriptions of the calculator's 700+ commands.The only mention of EVAL in any of the documentation that is currently available is in the description of the keypad, which tells you that when you press the EVAL key, the EVAL command is performed.

If you write a program that has the essential characteristics of a mathematical function and you want to use the function plotter to plot its output, then you will have an opportunity to explore the nuances of the function plotter.When an algebraic expression is plotted, it is evaluated both before and after the x-coordinate value is substituted in place of the independent variable name.If you use a simple algebraic expression to invoke your program, your program will be passed the literal name that you have designated as the independent plotting variable, instead of the x-coordinate value.If you have written your program so that it will return a numeric result no matter the setting of those two important CAS modes, the static value of the actual global variable that you have named as the independent plotting variable will be used instead of the x-coordinate generated by the function plotter.If you are lucky, you will see a straight horizontal line in the plot window, which will give you a clue that the y-coordinate values are all generated using the same value for the independent variable.More likely, you will have trusted the function plotter to automatically set the vertical range of the plot window, and it will have chosen a vertical range appropriate for the static value stored in the actual variable and then will have changed its value so that when plotted, the constant function no longer falls within the vertical plot range.It is easy enough to steer clear of this lovely business if you can control the urge to smash the calculator long enough to discover that this nonsensical behavior only occurs when there is an actual variable having the name that you have designated as the independent plotting variable.

If you play with many of the plotters, you'll eventually get an error that simply says "Interrupted", and you won't find anything anywhere that gives you a clue why this happens.If you call HP's help desk, they will advise you to delete the reserved variable `PPAR', which is a nested list that holds the plotting parameters.Almost all of the plotters use this variable, but the structure and interpretation of the nested list varies from one plotter to the next.The various plotters don't bother to insert a descriptive label in the list, so when you open a plotter with `PPAR' left over from a different plotter, the plotter that you are currently trying to use will be confused by the unfamiliar structure, and may attempt an illegal operation that will lead to the useless error message.

The PC connectivity works great once you have installed it correctly and have learned to disconnect and reconnect the cable as needed.The install utility requires you to select what you want to install from a list and then it copies the files that make up the manuals, connectivity kit, USB driver, etc.It gives you no clue that you will need to install the special USB driver, but if you guessed that you need it, you got lucky, unless you tried to follow the driver installation instructions included on the CD, which don't work.

In May of 2005, when my 49g+ was not quite ten months old, the delete key broke, so HP sent me a replacement.HP didn't ask me to return the broken unit, so I took it apart.Three different techniques are used to attach the keys to the underneath of the faceplate.The four keys that are used to move the cursor (the arrow keys) are held in place by a single rubber sheet that is attached to the faceplate.Each of the three colored keys is a separate part, with each individual key rocking on its lower edge.There are two shades of grey keys on the keypad, and a block of black keys.There is one molded plastic part for each of these, i.e., one molded part for the top row of keys, another molded part for the block of grey keys, and another molded part of the block of black keys.These parts are fastened to the underneath of the faceplate, and each consists of a frame that holds the individual keys, all one molded part, and with the individual keys separated from the frame except by two thin strips at their lower edges.If you have ever put together a plastic car model and have seen how the individual parts need to be cut away from a frame of sorts, you have a good idea of what these three molded parts look like.

All three techniques for holding the keys to the faceplate permit the individual keys to press against a little rigid bump on a sheet of stiff plastic that covers the circuit board.Each bump is roughly 5 mm in diameter, and there is a thin conductive coating on the underside of each bump.When force is applied to the center of the bump, it inverts with a pop, pressing the conductive coating against the circuit board and closing the circuit across the contacts that are exposed on the surface of the circuit board.Except for the bumps, the underneath of the stiff plastic sheet has an adhesive that holds the sheet to the surface of the circuit board.

The problem with the top row of function keys is that the bumps are located against the upper edge of the plastic sheet.The effect is that the bumps on the top row aren't rigid enough to invert correctly with a pop that will cause the conductive coating underneath to make solid contact with the circuit board.The replacement unit that HP sent me does not seem to have the same problem.This may be because the physical design was changed slightly, or it may be because the de-bounce algorithm in the earlier firmware exacerbated a problem with a weak contact, but it is more likely because the plastic sheet on the new keypad hasn't broken in yet.But even if the problem with the keys on that row not consistently registering returns, soon thereafter it will be rendered moot when the keys break.My Delete key broke because the two thin strips that hold it to its frame, broke in two under repeated use.I observed that the same failure mode was ready to happen with the Enter key and the F3 key as well.When those two thin strips break, the key will move around and will become unusable because it has a short protrusion underneath that must be positioned directly at the center of the little bump in the plastic sheet underneath.Having inspected this first hand, I cannot avoid the conclusion that all 49g+ calculators are doomed to premature death because of this ridiculously cheap design.

If Bill Hewlett were alive, he would surely have something to say to the person responsible for allowing his legacy to be tarnished in connection with this junk.HP urgently needs to make a design change to the 49g+, and then needs to send a new calculator to all of the present owners of these calculators.All that is likely needed is to use the design that is used with the arrow keys, for the other keys that are attached to their frames with the two thin strips.With that change, these calculators could easily last for one or two decades, but if HP doesn't do something about this real soon, these calculators are all going to be converted to expensive paper weights very soon, and the damage to HP's reputation as a calculator manufacturer may be irreparable.

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Product Description:
Students and financial and science professionals, warm up your fingers. The HP 49G+ Graphing Calculator provides basic RPN, algebraic, and textbook entry through its redefinable alphanumeric keyboard. It boasts more than 2,300 built-in functions, with 1.13 MB of user memory. An easy-to-read display accommodates up to nine lines, 33 characters wide, giving you ample room for graphing.
The HP 49G+ also provides advanced statistical, mathematical, scientific, and programming features, and comes with a convenient carrying pouch, batteries, and even a USB cable.

What's in the Box
HP 49G+ calculator, carrying pouch, batteries, USB cable, User's Manual (basic) and CD with User's Guide (advanced), connectivity software