42S display background matrix - Can it be "deleted"?


I was one of the lucky purchasers of the HP service 42S calcs.

I am still getting used to seeing both X and Y values (after 30 years of keeping Y in my head).

On my model, the values are displayed against a matrix or grid (for want of better words) of LCD dots. If I adjust the contrast of the display, the relative intensity of the background versus the numbers does not change much. I find this background rather annoying, and don't see any logical reason for its presence.

Is there some way to get rid of this background? (The service calcs did not come with any manual(s).)


My (old) HP42 has a similar 'problem'.

Does the HP17Bii (old and new) use the same display and, if so, have the same 'problem'?


The HP 27S, 42S, and 17BII (and presumably the 17B) all use the same display.


I think HP changed the display in recent years. I have an older 17B-II that has better display contrast (at least, it can be "turned down" so that the matrix dots aren't visible). My new 17B-II that I recently purchased as a backup has a display that (1) has a noticeably blue-green cast and (2) can't be turned down far enough to eliminate the dots.

Unfortunately, I missed the 42S service clearance by a day (Rats!), but I presume they were recent builds with the newer (worse) displays. This is purely conjecture on my part.


I'd have to double check, but I believe that the 42 I got from the late 2001 Indonesian batch didn't exhibit that behavior. Given the odd color you describe, it's possible that the current displays have polarization filters of inconsistant quality.


the contrast can be adjusted in keying simultaneously ON/+ for darker background and ON/- for lighter bacground.

this feature exist on all pioneer and clamshell models, as well as charlemagne.



The problem is that the contrast of the X and Y values AND the background change together. Doing the ON/+/- trick does very little to enhance the readability of the register contents. My 32SII looks much better.

I guess, as we used to say about malfunctioning software: "this is a feature, not a bug." (??!!??)



Unfortunately, it seems that the "contrast" adjustment in these calculators (and many other LCD devices) is really a "brightness" ("darkness"?) adjustment. Or, in other words, "level adjustment" instead of "gain adjustment". I wish that separate brightness and contrast controls were available, but have learned to put up with what's available.


Well, I'll be gol-durned! I've had my 42S for only several months, and I never knew about the contrast-adjustment feature (hadn't yet gotten through the manual). The black-matrix really bugged me and others when viewed from an angle.

There are 5 people in my office with 42S's (personal and employer-purchased). I'll tell 'em!

Possibly Related Threads...
Thread Author Replies Views Last Post
  AFTER HP-Prime update, Shift+Matrix CRASHES Joseph Ec 3 1,071 12-06-2013, 11:06 AM
Last Post: Joseph Ec
  HP Prime Matrix TERRIBLE bug and question uklo 19 2,748 11-25-2013, 12:10 PM
Last Post: Mic
  HP Prime: editing a matrix Alberto Candel 6 1,280 11-20-2013, 06:26 PM
Last Post: Helge Gabert
  Absolute Value and Matrix BruceTTT 5 1,172 11-11-2013, 11:52 PM
Last Post: Walter B
  (deleted post) deleted 2 748 11-03-2013, 06:24 AM
Last Post: deleted
  WP-34S Matrix operations with routine-local registers? Tom Grydeland 1 657 09-04-2013, 10:46 AM
Last Post: Marcus von Cube, Germany
  (deleted post) deleted 19 2,603 08-31-2013, 03:46 AM
Last Post: pascal_meheut
  Matrix Characteristic Polynomial - Reloaded. Ángel Martin 12 1,826 08-22-2013, 05:33 PM
Last Post: Thomas Klemm
  Matrix Richard Berler 3 793 08-18-2013, 06:24 PM
Last Post: Paul Dale
  Advantage/CCD Matrix Challenge Ángel Martin 1 659 08-09-2013, 06:22 PM
Last Post: Thomas Klemm

Forum Jump: