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42s new owner questions
09-25-2021, 02:38 AM
Post: #1
42s new owner questions
Hi all,

I just picked up my first HP-42s and I have a couple of questions.

1. Is it normal for the screen to have a small viewing angle? I can adjust the contrast and that in turn adjusts the view angle, but if I tilt the calculator just a bit it's unreadable. I am comparing this to my HP-41CV which is nice and clear at pretty much any angle.

2. The EXIT key seems to be much flatter than the other keys. All the other keys have angled key caps. The EXIT key seems only slightly angled. Is this normal, or is that just a symptom of wear?

Thank you!

DM41X, DM42, HP-41CV, HP-42S, HP-35S, HP 95LX - EDIT: I seldom post without an edit.
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09-25-2021, 03:22 AM (This post was last modified: 09-25-2021 03:24 AM by GreyUser.)
Post: #2
RE: 42s new owner questions
1. Yes. Adjust the contrast by pressing and holding down ON and then repeatedly pressing + or - to adjust as needed for your typical use. Yes, it is different and not as wide a use angle as the 41. New and improved don’t ya know.

2. Normal. Less likely to press it putting into the slip case.
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09-25-2021, 03:24 AM
Post: #3
RE: 42s new owner questions
(09-25-2021 02:38 AM)rexbinary Wrote:  1. Is it normal for the screen to have a small viewing angle? I can adjust the contrast and that in turn adjusts the view angle, but if I tilt the calculator just a bit it's unreadable. I am comparing this to my HP-41CV which is nice and clear at pretty much any angle.

Yes, it's widely acknowledged that the display, with its not-great contrast and small viewing angle, is a weak point of the HP-42S, and of other Pioneer-series calculators with the same 131x16 dot matrix display.

(09-25-2021 02:38 AM)rexbinary Wrote:  2. The EXIT key seems to be much flatter than the other keys. All the other keys have angled key caps. The EXIT key seems only slightly angled. Is this normal, or is that just a symptom of wear?

It is normal, and other Pioneer-series calculators have a flatter bottom-left key as well. I think the idea is that this makes it less likely that the calculator is turned on by accident when it's in its case.
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09-25-2021, 03:36 AM
Post: #4
RE: 42s new owner questions
Thank you both very much!

DM41X, DM42, HP-41CV, HP-42S, HP-35S, HP 95LX - EDIT: I seldom post without an edit.
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09-25-2021, 04:18 AM
Post: #5
RE: 42s new owner questions
IMO, one of the many things worthy of exploration in the 42S is the solver.

Hopefully you have a copy of the manual. You’ll need it until you learn the menu system and where all the goodies are hidden.
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09-25-2021, 04:38 AM
Post: #6
RE: 42s new owner questions
I'll be sure to check it out. I have a PDF version of the manual. Thank for the tip.

DM41X, DM42, HP-41CV, HP-42S, HP-35S, HP 95LX - EDIT: I seldom post without an edit.
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09-25-2021, 01:08 PM
Post: #7
RE: 42s new owner questions
(09-25-2021 02:38 AM)rexbinary Wrote:  1. Is it normal for the screen to have a small viewing angle? I can adjust the contrast and that in turn adjusts the view angle, but if I tilt the calculator just a bit it's unreadable. I am comparing this to my HP-41CV which is nice and clear at pretty much any angle.

The Pioneers with a recessed bezel have better readability than those with a flat display. Here's a comparison:
Recessed - https://www.hpmuseum.org/3qs/42s3q.jpg
Flat - https://www.hpmuseum.org/3qs/32s503q.jpg

Which do you have?
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09-25-2021, 02:20 PM
Post: #8
RE: 42s new owner questions
Has anybody ever investigated transplanting a display from the more recent 17BII+? Are they even remotely compatible?
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09-25-2021, 03:37 PM
Post: #9
RE: 42s new owner questions
(09-25-2021 02:20 PM)Dave Britten Wrote:  Has anybody ever investigated transplanting a display from the more recent 17BII+? Are they even remotely compatible?

They certainly appear to be equals, at least in outward appearance. The original display was made by Epson, obviously still in the business but it’s hard to say if they simply used the original design or tweaked it to be compatible with a totally different processor.

The original multiplexing scheme was likely the cause of the contrast issues since they used 16 rows and 131 columns with the physically driven pins being 16 x 64. This was no doubt due to the Saturn processor pin count and tab packaging limitations. Could you image the reaction when the display design engineer says, “yeah, I really need 64 more pins to do this the the right way”?

FWIW, this was changed in the 48 series by using two external column driver chips so there was no column multiplexing, doubling the pixel on time.

Given the physical layout of the 17Bii+, I suspect it would be quite possible to repurpose the unit into a 42S+ with a new faceplate and keyboard legends by just changing the rom image. I guess that tells you what HP thinks of the market size for an RPN scientific.

Has anybody taken a 17Bii+ apart? Photos?
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09-25-2021, 04:09 PM
Post: #10
RE: 42s new owner questions
(09-25-2021 02:20 PM)Dave Britten Wrote:  Has anybody ever investigated transplanting a display from the more recent 17BII+? Are they even remotely compatible?

This has been done, but they are not fully compatible, see here.
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09-25-2021, 07:37 PM
Post: #11
RE: 42s new owner questions
(09-25-2021 01:08 PM)Dave Frederickson Wrote:  The Pioneers with a recessed bezel have better readability than those with a flat display. Here's a comparison:
Recessed - https://www.hpmuseum.org/3qs/42s3q.jpg
Flat - https://www.hpmuseum.org/3qs/32s503q.jpg

Which do you have?

Mine is recessed.

If I am holding it in my hands at an angle using it and then say sit it down on my desk it becomes unreadable unless I change the contrast. Really anytime you change angels even slightly you have to change the contrast as well.

My 35s is pretty good at most angles, and my 41cv really doesn't have a bad angle at all. If either of these calculators even have a contrast adjustment I have never used it.

The display is really disappointing. At least I have a DM42 on the way from the Netherlands. Smile

DM41X, DM42, HP-41CV, HP-42S, HP-35S, HP 95LX - EDIT: I seldom post without an edit.
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09-25-2021, 08:19 PM (This post was last modified: 09-25-2021 08:23 PM by Steve Simpkin.)
Post: #12
RE: 42s new owner questions
(09-25-2021 07:37 PM)rexbinary Wrote:  ...
If I am holding it in my hands at an angle using it and then say sit it down on my desk it becomes unreadable unless I change the contrast. Really anytime you change angels even slightly you have to change the contrast as well.

My 35s is pretty good at most angles, and my 41cv really doesn't have a bad angle at all. If either of these calculators even have a contrast adjustment I have never used it.

The display is really disappointing. At least I have a DM42 on the way from the Netherlands. Smile

Yes, dot-matrix display technology came a long way in the 18 years between the HP-42S and HP 35S. HP considered a dot-matrix display for the HP-41C but the segmented display they chose had a much better viewing angle and contrast than the dot-matrix displays at the time.
I love my HP-48SX but its display is pretty poor when it comes to contrast and viewing angle.
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09-26-2021, 05:31 AM
Post: #13
RE: 42s new owner questions
As you can see, the S and SX had lcd’s with very poor contrast. The original G model production used the same washed out displays. That can be remedied with a blue or black lcd from a 38/39/49 or a later date code 48. The contrast is much improved in the later displays which increases the usable viewing angle range.
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