27S display - a show stopper? - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: 27S display - a show stopper? (/thread-200798.html) |
27S display - a show stopper? - Thomas Radtke - 10-11-2011 A colleague sold me this quite beaten up 27S today (for a very reasonable price):
While it has interesting features, I found the display to be not only problematic, but an imposition. Is it just this package with the protective cover making it almost unreadable? I know this kind of LCDs from the 18C/19B, but this one tops it all. For any viewing angle, a certain adjustment of contrast between black background and slightly readable characters has to be found.
What were your thoughts when you bought your sample (when it was new)?
Re: 27S display - a show stopper? - BruceH - 10-11-2011 Mine is fine and perfectly readable so it sounds like yours has been damaged. If you can post a picture of the screen then the knowledgeable folks here might be able to make useful suggestions.
Re: 27S display - a show stopper? - Thomas Radtke - 10-11-2011 Thanks for your answer, Bruce. Two angles, same contrast. The camera got the contrast in the top image much better than my eyes do.
[Edit: Used a flash light - under very bright light the problem appears to be less visible] Edited: 11 Oct 2011, 4:35 p.m.
Re: 27S display - a show stopper? - Neil Hamilton (Ottawa) - 10-11-2011 Hi Thomas, My circa '93 17bii from Singapore has this same "feature" while my 2 other 17bii's (both Indonsesia, later in the decade) do not. The later ones have a much wider field of view before "blacking out". Interestingly, the indicators (shift, print, etc.) do not seem to be affected to nearly the same extent as the dot matrix area.
What is the date and source of the 27S?
Re: 27S display - a show stopper? - Eric Smith - 10-11-2011 Quote:
That's because the dot matrix area has a much higher multiplex factor than the annunciators.
Re: 27S display - a show stopper? - uhmgawa - 10-11-2011 Quote:
IIRC Hosoda-san (www.finetune.jp) suggested this was due to a
Quote:
The annunciators might be multiplexed via a different rate/scheme
Re: 27S display - a show stopper? - bill platt - 10-11-2011 What does that mean? (or what is the multiplexer?)
Re: 27S display - a show stopper? - M. Joury - 10-11-2011 My 27S (3224S04249) is perfectly legible. No issues whatsoever.
Re: 27S display - a show stopper? - Lyuka - 10-11-2011 Quote:
for more information about it, take a look at
Regards,
P.S. Edited: 11 Oct 2011, 8:02 p.m.
Re: 27S display - a show stopper? - Eric Smith - 10-11-2011 Segments on a dot-matrix display generally aren't driven continuously. Some fraction of them are driven at any given time. For the dot-matrix area of the 17B/17BII/27S/42S display, one row is driven at a time, which is 16:1 multiplex. The annunciators are generally driven at a lower multiplex rate, though I don't know specifically for those calculators what the rate is.
Re: 27S display - a show stopper? - uhmgawa - 10-12-2011 Quote:
Ah, I think I see what my confusion was above. You were
The latter problem is due to the intended "off" pixels receiving
This appears unrelated to a glass quality issue as the
Quote:
The 17B I peeled open was very close except for what appeared Re: 27S display - a show stopper? - Thomas Radtke - 10-12-2011 Quote:I can tell not before tomorrow, but it's an early Singapore model sold in Germany.
Same here with the anunciators, they are perfectly readable.
Re: 27S display - a show stopper? - Thomas Radtke - 10-12-2011 Thanks for the links! So, replacing diode and capacitor might help?
Re: 27S display - a show stopper? - Thomas Radtke - 10-12-2011 S/N 2917Sxxxx
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