PRS-700 disassembly

[igorsk]

Originally Posted by Andybaby

Igorsk you missed atleast 1 screw. the one in the binding on the stop of the PRS700.

also igorsk is it possible to remove the innards without pealing off the touch screen?

Yes, I dropped the screw and could not find it at the time I took the photo. I found it later.
And no, no way to do it without removing the touch screen.

[gokalp]

Well, if anybody wants to repeat the removal process, be careful.

I had a couple dust specs in between the digitizer and the screen, and I peeled off the top bezel. All was fine, except that I was not peeling of the touchscreen, but instead splitting it in half. **The digitizer module is actually much thicker than the usual, e.g. compared PDAs and tablet PCs**

The digitizer looks like a resistive digitizer, and it has a thin sheet of metal frame just below the front bezel. On the top side of the reader there are 4 connections from this frame to the lower half of the digitizer, and it looks like these are thermally fused. So, when you pry it off, it peels the connections permanently. I tried shorting the layers using some aluminum foil, but it did not work. Finally, I tried the drastic measure, the Indium-gallium eutectic which is a wettable, liquid metal. Even that did not work. (Plus it is pretty hard to clean, so no recommendation there)

Anyways, I spoke to Sony, and ordered a replacement digitizer together with LEDs. It costs $69 FYI.

Looking at the digitizer, I do not think it is easy to split the LEDs and the digitizer. When I will replace it, I can post some photos if anybody wants me to.

PS: PRS 700 cannot be operated without the touchscreen, and as an engineer, I'd say that is not good a design. It should costs practically nothing to put a simple D-pad, but it gives redundancy in case of a touch screen failure.

[stasys]

gokalp,
Do you think it would be possible to replace this LED digitaser with some thinner one and get more contrast? Anyway their lighting is not very good.

[gokalp]

The digitizer itself is thin, it consists of a couple of sheets of plastic and metal. What makes most of the thickness is the LED side. It looked like they were a fused into a single piece, but it should be possible separate them, remove the LEDs or maybe retrofit something else.

For the contrast, I think the loss of contrast is mostly due to the topmost protective layer. Its texture is pretty matte to prevent reflections, but it also creates a blurry effect. The layers beyond looked like glossy surfaces, which should not decrease the contrast.

[Server]

sorry to hear you had to find out the hard way. My understanding from
igorsk's autopsy was that the digitizer was one piece and the LEDs were
another piece. I suppose from an engineering point of view, sony had to
compromise on the cost factor to utilize a touch panel that would also be
part of the LED lighting system since we know that eInk can't be backlit.

Myself, I still love the touch screen for navigation. It just seems natural.
The glare or 'haze' non-issue issue, has mostly to do with poor insufficient
lighting by users.

If Sony wanted to, they could have done away with the acrylic plastic
backing, but I think it not only acts as a hard surface to poke with the
stylus but also to act as some level of protection from marring the e-ink
display associated with constant touching.

At the end of the day, let sony deal with the dust issues. (ie. unit swap)


thanks for the heads up.

[stasys]

Originally Posted by gokalp

The digitizer itself is thin, it consists of a couple of sheets of plastic and metal.

And digitazer is four wires? Can you, please, measure the digitazer and place that it occupies inside reader? I think it is worth to put there some stand-alone digitazer and get rid of LED light panel. I like touch panel on sony700 but I want to have more contrast.

[el.astrologo]

Originally Posted by stasys

And digitazer is four wires? Can you, please, measure the digitazer and place that it occupies inside reader? I think it is worth to put there some stand-alone digitazer and get rid of LED light panel. I like touch panel on sony700 but I want to have more contrast.

I'm with stasys on this one however my electronics knowledge is close to zero so I can't add any thoughts on different ways of solving this

Hope you guys are able to crack this up... Not literally of course

[gokalp]

Server,
I am sure that one can remove the LEDs from the digitizer somehow. They should have been independent modules at some point, and and in the worst case, they would be separated by force.
For the touchscreen, don't get me wrong I love the touchscreen. I know that it reduces the clarity and the contrast, but I am not bothered by it as the screen is still very good. What I do not get is why could not they put an additional, simple, cheap D-pad. It would cost practically nothing.
I do not like sending gadgets to manufacturers for warranty, as I absolutely hate waiting indefinitely to get them back. Plus I like playing with things and fixing them, so I usually choose the DIY route.

stasys and el.astrologo,
Yes, it has 4 wires that eventually form a copper ribbon cable. I did not pay a lot of attention to the ribbon cable, so I'll check it out when I open the device again to replace the panel. I'll also measure it and take some photos to give you an idea.
As far as I can see, you can remove the digitizer and the LEDs to expose the screen. If you put a protective plastic in front of the e-ink screen, you can even make a clamshell type device where you "flip" the touchscreen up to see the e-ink screen more clearly.
I looked at the technologies for digitizers, and I am sure this is a resistive touch screen formed by two layers coated with indium-tin-oxide making a short at the point pressed. If one wants to replace, there should be compatible ones around.

[maxlawbr]

Hello,

Nice work.

I'm experiencing a problem. My 700 fall of (2 feet), and the right plastic part stayed apart from the metal.

I took off the screws and fixed the right side, but my power switch can't stay in place, the tiny little internal switch didn't fix the external plastic part.

I now put the up plastic cover a little apart, and pressed the plastic to the left side, but it didn't attach, does anybody know to fix it?

Thanks a lot.

Max

[Server]

You might want to ask AndyBaby as I remember he wrote a way to fix
a separation issue.

[maxlawbr]

OK,

Thanks, I'll look for him.

Thanks again,

Max

[gokalp]

Ok guys, here are the updates.

I have finally received the part that Sony sent. And guess what they have sent the light guide, which is a thin plastic sheet. I called again and they are telling me that the digitizer is $199.38. I am going to call them again to return the part.

In the meantime, I have ordered a 6.5" resistive digitizer from Mouser:
http://www.mouser.com/Search/Product...4DJrRFjNIx0%3d
It's $29.92, but it transmits 86% light compared to the standard 80%. One problem though, since it is 6.5" and not 6" it looks like it will not fit without trimming the sides by a couple of millimeters.

BTW, I was wrong before: the digitizer and LEDs are separate modules. The digitizer is 14cm by 10.6cm, and 1~2mm thick. It has 4-wires.

After I opened the device, I tested the effect of the digitizer on the screen quality. Apparently, most of the complaints I hear are due to the lower half of the digitizer panel. When it is removed, the screen looks more contrasty and clear.
Here is a picture:


Given the dimensions of the touch panel, I have decided to try something different first. Instead of replacing the digitizer on the front, I will move the digitizer to the back of the device and swap the left-right connections. I have seen this sometime ago in Pop Sci:
http://www.popsci.com/gear-gadgets/a...re-fat-fingers
The idea is to put the touch screen on the back of the LCD and overlay the images of the fingers. Now, obviously I will not have the overlay, but I think it is still very usable with the digitizer attached to the back, except the onscreen keyboard perhaps. This should retain the touch screen capability and the gorgeous e-ink screen.

What do you think?

[stasys]

I think that touch panel behind reader will not work well for dictionaries and for Mahjong game (yes, it is made for 505 but launches on 700, just no controls are ported yet).

For page turning this solution may be OK, but for that you can stick there any 3.5" panel that cost on ebay 9$.

I'd prefer to stick touch panel on front. Unfortunately Mauser do not give external dimensions in datasheet, so I will wait till your panel arrive, then order mine.

[stasys]

gokalp, any news on Mouser touch panel?

[gokalp]

Yes, good news actually. I managed to finish the mod, and I am very happy with it. I posted the results in a separate thread here:
https://www.mobileread.com/forums/sho...d.php?p=371766