HP 42s display



#8

Hi folks,

Well at long last I finally added a 42s to my collection. What a little jewell! I especially like the solver application.

I do notice, however, that the display contrast has to be adjusted to suit the viewing angle. A more perpindicular viewing angle requires more contrast than a shallower angle.

Is this normal for a 42S?
Thanks and best regards,

Hal


#9

That's normal for any passive LCD, though it has less effect when the multiplex rate is low, so you'll notice it less on calculators with seven-segment displays and more on those with dot matrix displays.

Edited: 27 Feb 2008, 3:09 a.m.

#10

Hi Hal,

Congradulations on your new HP-42S. My favorite calculator.

The early versions have a plastic window over the display - thus the dispay area is fairly flush with the adjacent calculator. The later versions do not have this plastic cover and thus the display is recessed into the calculator. I have both versions and find that the later models have a higher contrast than the earlier models. I think the extra plastic cover reduces the constrast somewhat.

But the earlier version (depending on the rom version) can be programmed to run at double speed.

Bill


#11

Quote:
The early versions have a plastic window over the display - thus the dispay area is fairly flush with the adjacent calculator. The later versions do not have this plastic cover and thus the display is recessed into the calculator.

While there are two versions, one with and one without the plastic window, the LCD is in the same position depth wise in both models.

There are two differences between the models:

1) The early model with the plastic window covering the LCD has an anti-reflective coating, the same as was used on the Voyagers which preceded the Pioneers. The first version of the LCD had a high polish polarizer, again, same as the Voyagers which is perhaps why the window with the A/R coating was used.

2) With the second model, when they removed the window they went to a matte surface LCD polarizer.

It is my belief that this change came about due to several factors. One is that the windowed displays have a nasty habit of collecting dirt particles between the LCD and window. Two, when they designed the 48 series they realized they would have trouble with big windows in front of the LCD. So, with the 48's, they changed to a matte LCD finish to eliminate the window. This change then filtered back through the Pioneer product line with the 14B being the only model that didn't get the display rework.

FWIW, I too prefer the second version and while the contrast is many times less than perfect, one learns to live with it :^)

#12

I think all HP42S units can be programmed for speed increase up to double speed. I have a late 1993 HP42S (SN 3328Sxxxxxx), ROM version C. ("C 7" is shown when the routine at 023F5H is executed.) It is just like earlier units, in that it can be speed adjusted by changing the value of the nybble at location 40300H. Of course, any machine reset restores the default value of 7.

I've used many HP calculators since the HP-35 first came out (and I still own more than 25 of them). The HP42S gets my vote for the best pocket-sized calculator of all time...nothing else comes close. I used a HP-15C as my work calc for ten years before I got the HP42S 11 years ago. IMO the HP-15C falls far far short of the HP42S in speed, function, and ease of use. The HP-15C is prettier and its simple display has much better contrast, but it is much harder to work with one hand. I always wonder, when I read all the "bring back the HP-15C" clamor, if those folks have ever extensively used BOTH the HP-15C and the HP42S.

The HP42S design is 21 years old. Just think what would be possible today in the same size, such as bigger and better display, micro-SD card I/O, all HP17BII functions added, more memory, faster speed...but what battery would fit?

Mike


#13

Quote:
The HP42S design is 21 years old. Just think what would be possible today in the same size, such as bigger and better display, micro-SD card I/O, all HP17BII functions added, more memory, faster speed...but what battery would fit?

The new, silver 17bII+ seem to be a good home for HP42s resurrection, same size, better display contrast (as seen on pictures shown here), all it needs is a mini SD and probably equation support as on the HP35s, AFAIC :)
Cheers,
Reth

#14

Reth

Nice to see your posts again.

tm


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