Variable contrast on PSR-E4xx and PSR-EW4xx (and perhaps more). Any interest?

[EB5AGV]

Hi all,

I have just got a PSR-EW410 and it has one very inconvenient problem: display contrast is not good in the position I use it, which is on the second tier of a 2-tier keyboard support. It is almost impossible to read it on that position if I sit, and that is not a good thing 

I have been looking for information on that problem, which seems the same for at least all the 4xx series, and have not found any solution. So, as an electronics technician, I have decided to investigate the problem, using the service manual for one of them... and I am almost sure I have the solution

Is this a problem interesting enough for people to document and share it?. Please, let me know on this thread, along with the model you have, so I can get the full picture of the extent of this problem.

I will work soon on my unit and will have definitive results. Keep tuned! 

Jose

[Toril S]

I have a PSR model, but am very interested in this! So please let us know!

[SeaGtGruff]

This is definitely an issue that comes up from time to time among PSR-E owners. I believe that— as you've alluded to, whether intentionally or not— the real issue isn't the contrast per se, but rather the viewing angle. Even LCD computer monitors suffer from this issue, although they're usually designed to have a wider range of visibility from above or below and from left or right. The more "primitive"(?) type of LCD screen used on the PSR-E models seems to have a very narrow range of visibility. It might help to be able to adjust the contrast, but I suspect that this still wouldn't completely overcome the narrow range of optimum viewing angles.

[SciNote]

Sounds like he's working on an electronic hack to solve the problem and "synthesize" (pun intended) a contrast control.  Interesting project, but of course, if it involves opening up the keyboard and rewiring anything, then bye-bye warranty!

In my experience, the contrast control on the lower-end type of LCD display does, indeed, affect the viewing angle, at least to some extent.  I've seen situations with various displays that are difficult to read at a particular angle become much easier to read with an adjustment of the contrast control.  It essentially just moves the optimal viewing angle, because, in my experience, once you adjust it to be visible at a steep angle, then when you look at the display at a more conventional angle, it is nearly unreadable.

[EB5AGV]

This is definitely an issue that comes up from time to time among PSR-E owners. I believe that— as you've alluded to, whether intentionally or not— the real issue isn't the contrast per se, but rather the viewing angle. Even LCD computer monitors suffer from this issue, although they're usually designed to have a wider range of visibility from above or below and from left or right. The more "primitive"(?) type of LCD screen used on the PSR-E models seems to have a very narrow range of visibility. It might help to be able to adjust the contrast, but I suspect that this still wouldn't completely overcome the narrow range of optimum viewing angles.

Yes, you hit the nail on the head!. The viewing angle is narrow, but the center of that narrow margin can be modified when you change the polarization voltage on the LCD. And that is the contrast adjustment when seeing from a fixed point. The LCD works by polarizing a material so its molecules align at an angle depending on the voltage applied. That gives you some range of operation which effectively results on different center viewing angles.

Of course, any setup will affect other viewing positions. But the best is to be able to adjust it, not just have one option which works fine only on ideal positioning conditions.

Jose

[EB5AGV]

Sounds like he's working on an electronic hack to solve the problem and "synthesize" (pun intended) a contrast control.  Interesting project, but of course, if it involves opening up the keyboard and rewiring anything, then bye-bye warranty!

Of course that will void the warranty. But I will sacrifice mine if other people could benefit on this trick. Because I think that people keeps using their keyboards well passed the warranty, right?. So you can live with the problem for 1, 2, 3 years (depending on warranty time) and then, finally, enjoy a better-viewing display 

In my experience, the contrast control on the lower-end type of LCD display does, indeed, affect the viewing angle, at least to some extent.  I've seen situations with various displays that are difficult to read at a particular angle become much easier to read with an adjustment of the contrast control.  It essentially just moves the optimal viewing angle, because, in my experience, once you adjust it to be visible at a steep angle, then when you look at the display at a more conventional angle, it is nearly unreadable.

Yes, as I commented on the previous message, there is only one ideal viewing angle for each contrast setting. But this is exactly what you want on a narrow viewing angle display, be able to precisely select that angle.

Jose

[joseleno]

Very interested as you said IS a problem.
Perhaps another solution is to tilt a little bit the unit o better just the display.
So if you can find a way to change the display inclination it will also work.

[EB5AGV]

Very interested as you said IS a problem.
Perhaps another solution is to tilt a little bit the unit o better just the display.
So if you can find a way to change the display inclination it will also work.

Well, I guess an electronic way is better than a mechanical way.

I am still trying to get a suitable keyboard to try my idea as finally decided my pristine (bought just weeks ago) PSR-EW410 was not going to be my first modification prototype...

Jose

[SeaGtGruff]

Can't say I blame you. Just opening up the casing would be enough to void the warranty, and it's not wise to do that with a newly-purchased keyboard.

[Toril S]

Hello A little off topic, but I saw on YouTube a man repairing the display of old keyboards, such as the PSR 2100. They have a light tube that dims with time and finally goes dark. These tubes are not to be found any more, but he put in an LED strip instead. Then there was the tricky part of routing the right amount of power to the LEDs. A lot of work with small parts and a good deal of technical language, but the end result was very good! But yes, you have to take the keyboard apart, and there are so many peaces!!!