HP-15C Problem

[Jan Poulsen]

I just received my HP-15C and I was ecstatic :-) I was brought up on the
HP-67 and the HP-15C does it all and more.

Just to try it out, I entered the Moon Lander program from the HP-67, which
was my favorite game back then. Anyway, I start the program and all I get
is a blank screen, and the screen stays blank until the moon lander finally
crashes. Each PSE command should display values of altitude and speed,
followed by amount of fuel available, but the screen just stays blank.

I figured maybe my unit was defective, so I entered the code below in the
HP-15C emulation software that came with the package. The result is the
same, the screen goes blank and stays blank until an overflow occurs.

001 - 42,21,11 - f LBL A
002 - 43 26 - g Pi
003 - 20 - *
004 - 42 31 - f PSE
005 - 43 11 - g x^2
006 - 42 31 - f PSE
007 - 22 11 - GTO A
008 - 43 32 - g RTN

If I single-step (SST) through the code, then the result continues to blink
while I am on the PSE command, and stops blinking as soon as I SST to next
command. Putting multiple PSE commands after each other does not solve the
problem either, it just slows down execution. If I replace the PSE with R/S
then it all works fine, but that wasn't the intention.

So now I'm wondering if I'm doing something wrong. If anyone has a good
idea I am all ears ;-)


--
Med venlig hilsen / Best regards,
Jan Poulsen

[Virgil]

In article <4ed7b8f5$0$277$edfa...@dtext01.news.tele.dk>,

I entered your program on my HP15C, and with anything but zero as a
starting value, the numbers displayed at the PSE steps just keep
increasing in magnitude to overflow.

There is a way to reset everything, including some internal glitches:

With the power off press down and hold down the ON key
Then press down and hold down the - (minus) key (row 3 column 10)
Then release the ON key, the release the - key.

This is supposed to clean things up that cannot be cleaned up any other
way, and has worked at least twice on my HP15C when I was getting odd
results.
Hope it works on yours!
--

[greenchile505]

There is a known "PSE bug" in the 15C LE... head over to the HP Museum
to learn more.. We are waiting for a firmware update. The new 15C LE
is programmable.

[Jan Poulsen]

> "greenchile505" wrote in message
> news:61d9c4bd-a563-4fb7...@r28g2000yqj.googlegroups.com...

Thanks!!!

I found a good explanation at
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=1089

So now I'll just wait for HP to make an update available for my HP-15C LE.


Regards,
Jan

[Jan Poulsen]

> "greenchile505" wrote in message
> news:61d9c4bd-a563-4fb7...@r28g2000yqj.googlegroups.com...
>

[greenchile505]

What I meant when I said "The new 15C LE is programmable" is the
firmware can be updated, with a serial *programming* cable and a PC.
There are (6) points in the battery bay for making this connection.

[Jan Poulsen]

> "greenchile505" wrote in message
> news:d1a2e789-76df-48ce...@q9g2000yqe.googlegroups.com...

I noticed the connector in the battery compartment when I got the unit, and
I found this article about making a serial cable.

http://hhuc.us/2008/Interfacing%20to%20the%20HP20b%20V3.pdf

Perhaps someone will, or already do, manufacture such a cable for those of
us who are fumble-fingers with a soldering iron ;-)


Regards,
Jan

[Jan Poulsen]

Here's the work-around I came up with for the PSE issue on the HP-15C LE.

42,21,.9 f LBL .9
43, 4, 9 g SF 9
31 R/S
43, 5, 9 g CF 9
43 32 g RTN

Any time you need the "PSE" function, substitute with "GSB .9".

It's not ideal, but it signals the HP wants attention, and you can also
enter values before pressing R/S.


Regards,
Jan

[greenchile505]

There is a person by the name of G. Wright, who is an active member of
the HP Museum forum, who has the proper programming cables for sale,
at a very reasonable price. He only charges for shipping, and he ships
overseas.

Incidentally, the cables were manufactured or produced (and provided)
by HP!


Cheers.

[nop...@gmail.com]

It worked for me.

Thanks, big time. Love my old 15C.

- geo

[Virgil]

In article <1ce01d17-3dfd-4fe0...@googlegroups.com>,

I have two HP15C's, on one of which the pause command, PSE, works
properly in programs, pausing a running program to display the contents
of the X register for about 1 second, but on the other PSE apparently
pauses the program but does not display.

The one for which it does not work is labelled "Limited Edition".

In addition, the lettering on the operations printed above and below
each key is much brighter on the "Limited Edition" model, being yellow
above the keys and light blue below, while on the other one it is a deep
red above the keys and a darker blue below them.
--
Virgil
"Mit der Dummheit kampfen Gotter selbst vergebens." (Schiller)

[Leviatan]

Y va Virgil y suelta:

> I have two HP15C's, on one of which the pause command, PSE, works
> properly in programs, pausing a running program to display the contents
> of the X register for about 1 second, but on the other PSE apparently
> pauses the program but does not display.
>
> The one for which it does not work is labelled "Limited Edition".

This is a well documented bug in the Limited Edition HP-15C.

--
Un saludo,
Alberto

[A.L.]

Is there somewhere list of bugs?

A.L.

[Virgil]

In article <35lpfadia010u2edc...@4ax.com>,

To the best of my knowledge, HP15's in general are remarkably bug free.
And the non-pausing pause command, which seems limited to only the the
ones marked "Limited Edition" on their front, are the only ones I am
aware of with even that one bug.

[Leviatan]

Virgil dijo el 09/03/2015 :

>> Is there somewhere list of bugs?
>
>
> To the best of my knowledge, HP15's in general are remarkably bug free.
> And the non-pausing pause command, which seems limited to only the the
> ones marked "Limited Edition" on their front, are the only ones I am
> aware of with even that one bug.

15C Limited edition uses a modern ARM microcontroller to "emulate" the
old microprocessor and runs the same program as the original 15C
(although about 150 times faster).

The two only claims about it are:

- The PSE command bug, that you have just discovered
- The low battery indicator (*) doesn't work, what linked to the lower
battery life, compared with the old version, makes it a bit "risky" to
store very long programs in the calculator

--
Un saludo,
Alberto

[Virgil]

In article <cm50p2...@mid.individual.net>,

I have a 15C marked "Limited Edition" and a 15C not marked as a limited
edition that work at the same high speed.

[Leviatan]

Virgil nos ha comentado:

> I have a 15C marked "Limited Edition" and a 15C not marked as a limited
> edition that work at the same high speed.

The easy way to difference the two versions is with the batteries. The
old one uses 3xLR44 (or SR44) the Limited edition uses 2xCR2032.

Try to solve an Integral with high precision and you will see that the
speed is amazingly higher in the Limited edition.

--
Un saludo,
Alberto

[BartdB]

Unfortunately that is not all. For example some self tests listed in the 15C-LE manual can corrupt the memory.

For a more comprehensive list of bugs see:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=1089

Best regards.