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42s programming
Message #1 Posted by tech alum on 20 Feb 2007, 10:05 a.m.

I was wondering if anyone could help with programming a "time value of money" program into my 42s. I know it is on pg 193 of my manual, however, I am not up on programming this calc. Any help with specific keystrokes etc., would be appreciated - thanks!

Re: 42s programming
Message #2 Posted by Les Wright on 20 Feb 2007, 12:17 p.m.,
in response to message #1 by tech alum

I hate to be one of those surly "RTFM" folks that are all over forums and usenet, but in this case you really do need to read back a bit in the manual.

The p. 193 TVM program is basically used with the Solver program. Page 194 tells you how to use it once it is in the calculator. To get it into the calcalutor, you need to get in to program mode (Shift Prgm), get to the top of a fresh stretch of program memory (GTO ..) and key in the steps on p. 193.

Now I could walk you through how to key in MVAR, RCL ST X, etc., but that would be tedious. The complete list of the calculator's functions starts on p. 310 and has information on keystrokes for each. Entering an instruction like RCL ST X can be tricky to the uninitiated--you basically hit the decimal point after RCL and the menu of choices appears. As far as navigating your way around the menu structure, you really do need to crack the earlier chapters of the manual. After a certain point it becomes fairly intuitive.

HP was known for writing great manuals in the 70s thru to the early 90s, so I am sure everything you need to know is there.


Re: 42S programming
Message #3 Posted by Karl Schneider on 21 Feb 2007, 12:40 a.m.,
in response to message #1 by tech alum

"tech alum" --

As Les implied, it would be asking too much for a detailed keystroke sequence, and the manual is certainly adequate. However, but there are several very helpful hints I can provide:

  1. Before entering the program, create each of the five named variables using ALPHA mode by storing zero or any other value to them. That way, when you select the MVAR or RCL functions during programming, the named variables will appear in menus, and you can just select them by pressing a softkey. Otherwise, you'd have to type their names each time, letter by letter. It's better to do that only once, when creating the variables.

  2. Select the LBL and MVAR commands from the PGM.FCN menu (one level up for MVAR). It beats entering the command names letter by letter in ALPHA mode.

  3. Similarly, select the FC? command from the FLAGS menu.

  4. Access "ST T" (stack level t) by selecting it from the menu brought up by "STO ." (decimal point), as Les said.

  5. All other commands are on the keyboard.

My colleague probably did not know these tricks. He liked to use the 35-line program to calculate if a mortgage refinancing might be attractive. He lost all the memory on his HP-42S during a battery change (a common problem), and then complained how long it took him to re-enter the program each time. I believe that I mentioned that I could enter the program in 5 minutes, and also recommended that he buy a financial HP. He soon got a Chinese-made HP-12C.

-- KS

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