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HP Forum Archive 08

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49g reflections
Message #1 Posted by Walter Smits on 25 Apr 2002, 8:09 a.m.


I'm new to this forum, so I hope I'm not asking something that's been asked a thousand times before...

A week ago I bought an hp49G, till now I'm perfectly happy with it. But, the display shows some beautifull rainbow-effects and seems to reflect every lightbeam it can find. Found some sites on the internet about completely removing the screencover, but that's something I'm not going to do. Has someone ever tried to use an anti-reflective film or coating? I came across some sites about PDA protective sheets, maybe someone has tried these?

Thanks in advance, Walter.

Re: 49g reflections
Message #2 Posted by Tom (UK) on 26 Apr 2002, 7:49 a.m.,
in response to message #1 by Walter Smits

I thought the rainbow pattern problem had been solved with the 'new' screen cover (the early one was also easy to scratch). How old is your '49G? (see 'decoding serial numbers' on this web site for more info). I think it was something to do with a polarisor being needed.

I think it is a bad idea to try and remove the screen cover because the case is too weak without it. I have heard that the blue case cracks near the screen because of the stresses if it is removed. The HP48 has a much stronger case and does not need a screen cover - however only the latest HP48's have the higher contrast screen that the HP49 comes with.

Anti reflective coatings are common on glass (e.g. camera lens and CRT screens) but I've not heard of a stick on anti reflective sheet - do the protective ones really cut down on reflections or is it sales hype? Do they incorporate a polarisor which may help in this case?

Please post on this site if you find an answer / solution.

Re: 49g reflections
Message #3 Posted by Walter Smits on 26 Apr 2002, 10:54 a.m.,
in response to message #2 by Tom (UK)

Hi Tom,

Thank you for replying. I just checked the serial number, and I fear I've bought a rather old one... 1999. The display is indeed very sensetive to scratches, yesterday I bought a 48 softcase to protect it from dust, but as soon as the display came in contact with its zipper it made a huge scratch from top to bottom. Altough I bought it a week ago, I'm definitifely going back to the shop, especially now I know that it's been made 3 years ago.

About those protective sheets - today I bought a set of them, but it only makes it worse. First, because they're made for PDA's they're made from some kind of special plastic to make the toutchscreen work, witch doesn't make it that clear (kind of pixelizes). Second, because you've got to stick them to the screen you get, depending on your handyness, some or a lot of bubbles between the screen and sheet. That looks really ugly and makes the screen even more unreadable. And even if you could get it perfectly on the screen and it was 100% clear, I doubt if it takes away the reflections.

Concluding, not a good idea (especially considering the high prices - EUR 18 here in Holland).

I'll go back to the shop next monday, see what they'll do.

Thanks again for your help.

Cheers, Walter.

Re: 49g reflections
Message #4 Posted by Walter Smits on 26 Apr 2002, 1:00 p.m.,
in response to message #3 by Walter Smits

BTW, before I tried those protective sheets I put the polarizer of my SLR on top of the display, hoping that that would help (like Tom mentioned), but except for some beautifill color effects in the cover it didn't work. But what I did notice is that unlike many other LCD's that turn entirely black when you look at it through a polarizer, this one looks more like one of those lava-lamps; some black blobs that move around the screen when I rotate the polarizer. No idea if that's normal....

cheers, Walter.

49g reflections - my 'solution'
Message #5 Posted by Tom (UK) on 29 Apr 2002, 1:35 p.m.,
in response to message #3 by Walter Smits


Over a year ago HP (UK) exchanged my HP49 for a newer one after I complained about the screen and software downloading problems (my original HP49 was a 1999 issue and aparently also had a comms fault). I don't know if HP (Holland) do anything similar or if the time has run out for this offer.

If the shop gives no joy, try the importer as they may be authorised to replace your calculator. However since HP have tightened their belt (to make the Compaq merger?) your request may fail.

Note: Some of the very latest HP49 calculators seem to have a problem with the key pad ink wearing out, I think this only affects the Chinese built units and is caused by bubbles in the paint on the key tops.

You could just try to order a new screen cover or send it back to HP for an 'in warranty' repair, I think I've seen a web page saying the screen cover can be removed by pushing it out via the RS232 port - if you do this yourself you will probably invalidate the guarantee so be careful!

Keep us posted on this web site on how it goes.

All for now, Tom.

Re: 49g reflections - my 'solution'
Message #6 Posted by Walter Smits on 30 Apr 2002, 8:24 a.m.,
in response to message #5 by Tom (UK)

Hi Tom,

Before I'm going to complaint at the shop or HP I'm first going to contact the Dutch Consumer Organization, just to know what my rights are. In a week time I've heard about just too many other problems that can happen (now bad keypad ink and faulty comm ports too) that I think about trying to change it for a 48. I bought this calculator for double checking my calculations, but yesterday it gave a negative result (-1) for a simple integration (|cosx|dx from 0 to (3*Pi)/2). This one is easy to catch, but one starts wondering what other less obvious faulty results it gives when it simply doesn't check for such a fundamental error (maybe -1 is possible when traveling through a black hole, but certainly not on Planet Earth). In the latest ROM this bug apparently has been solved (tested it in the YorkeM emulator, 'cannot determine sign' or something like that) but that one isn't supported by HP. And apparently they don't plan to do so either.

Or am I just expecting too much?

Thanks for all your replies, Walter.

Re: 49g reflections - may I?
Message #7 Posted by Vieira, Luiz C. (Brazil) on 26 Apr 2002, 12:06 p.m.,
in response to message #2 by Tom (UK)


I have an earlier 49G (Y2K) and the first thing that called my attention was the protective adhesive that "covers" the transparent cover. I did not remove it so it would keep protecting the plastic cover, but the viewing angle is smaller than the 48's usual. In fact, it is a bit harder to see what's written in the 49's display, if compared with the newer 48's, that comes with the same LCD and has no effective protection.

Anyway, the 49's cover is scratch-free. I would suggest finding some sort of transparent plastic adhesive that could be placed over the 49's cover. As it is not the LCD itself, this is going to be harmless.


Re: 49g reflections - may I?
Message #8 Posted by Walter Smits on 26 Apr 2002, 12:47 p.m.,
in response to message #7 by Vieira, Luiz C. (Brazil)

Hello Luiz,

Mine had this piece of plastic on the cover too, but I removed it almost immediately after I bought it as I wasn't aware of the potential problems. Tried to put it back, but it wouldn't. If the place where I bought the calc doesn't want to change it for a newer one, I think I'll have to use the PDA screen protectors.

Think I should have checked this forum *before* I bought the machine.

Thanks for the suggestion, Walter.

Re: 49g reflections - may I?
Message #9 Posted by koyote on 30 Apr 2002, 3:31 a.m.,
in response to message #8 by Walter Smits

Incidentally- the PDA screen protectors can be applied without bubbles by using a "scraper" (I use a thick stock business card on my visor).

And while most of them aren't totally smooth, some appear to be-can't say which brands, since the ones I buy aren't (smooth)

But why not just use the clear vinyl that "no adhesive" window stickers are made of?

Re: 49g reflections - may I?
Message #10 Posted by Walter Smits on 30 Apr 2002, 8:38 a.m.,
in response to message #9 by koyote

Hi Koyote,

They did come with such scraper (just a thick piece of paper). That works quite good, but it's almost impossible to keep it clear from dust when applying. But if I have no success changing the calculator I won't have any problems with 'bubbles'.

A thing I did notice with those sheets is that they apparently produce lots of statical electricity (likely to support handwriting recognition). Don't know if that's so good for the display (you can clearly see that some spots temporarily 'turn on' when rubbing the sheet).

Can you tell what brand you use?

Thanks for your reply, Walter.

Re: 49g reflections - may I?
Message #11 Posted by Koyote on 30 Apr 2002, 1:03 p.m.,
in response to message #10 by Walter Smits

Heyo, I can't find the packaging, If I recall correctly it is "Fellowes" (blu and gold packaging).

I've never had issues with static, the protectors are lightly textured physically for pen aid.


Re: 49g reflections - may I?
Message #12 Posted by Walter Smits on 1 May 2002, 11:10 a.m.,
in response to message #11 by Koyote

Hi Koyote,

Seems like they're the same as I've got, "WriteRight/Fellowes". Maybe I should try them again.

Thanks again for your responses, Walter.

Re: 49g reflections - solved
Message #13 Posted by Walter Smits on 10 May 2002, 1:21 p.m.,
in response to message #1 by Walter Smits

Hi again,

I'd like to say a big thank you to all who helped me here, and especially to the shop where I bought my calculator, if they happen to be around here. Great service. They kindly replaced my old one with a newer version, with a good display.

Maybe something to add: it wasn't actually that easy for the shop to get it replaced. I was very lucky they had a newer one in stock, because the HP distributor refused to believe the story - about newer versions and better screens. Even after the salesman actually 'prooved' it by placing the two versions side by side. They (the distributor) stated that it only applied to units sold in the US, not to European ones, while it is clear that all units are produced in either China or Indonesia. It's a shame.

This one has without doubt a much clearer screen and is almost clear of rainbow effects (unnoticable). I'm not sure if it is more scratch resistent, I'm not going to try. Already sticked some plastic foil on it, just for sure. After some practice you can apply it almost without any bubbles, so it'll be as good as unnoticable.

Thank you once again,


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