The problem is similar to
http://talk.maemo.org/showthread.php?t=74007
In order to replace the whole cable - the seemingly safest repair route - ten screws have to be removed, and though eight of them were unfastened with little problem, two of them are now utterly destroyed. But until they give way, and allow to see the part of cable which is within the screen, there is no way to replace the cable.
Even if I knew how to solder wires, the flex cable (connecting screen and keyboard) would be too delicate: about thirty very thin, closely situated wires. And even worse, the part of the torn cable attached to the screen is very short - one or two millimetres.
For now: how can I activate PC suite mode on N900 when touchscreen is entirely non-working? With keyboard only? So far, camera is the only application successfully functioning on screen-less N900. But in order to see/download images from N900, I need to be connected to it. Usually, I press "PC Suite Mode" in dialogue and then "sudo gainroot" and "ifup usb0" in XTerm. How can I do this without a screen?
I would be grateful for any advice or help. The screws are rusty, I will look around for a TV which might be used as a temporary screen for the N900, and I have to find more keyboard shortcuts.

Hm, I'm currently refurbishing my old N900 that got run over by a car two years ago. It came out surprisingly well, the biggest defect being the snapped flex cable. I ordered a replacement one on ebay, which will hopefully arrive soon.

Anyway, that phone ran an old firmware (1.1?) and I can access it over USB without using the screen. Maybe you could try flashing 1.1 (without flashing MyDocs, of course).

On a side-note, that phone starts vibrating (in an on-off pattern) as soon as it's booted. I thought that might be some emergency thing due to it being head-less. Does yours do that, too?

I have ordered a replacement (about ten dollars) from EBay, too. But it will take at least a week to arrive, likely more. And do you know what should be done about the white adhesive attaching flex cable to the metal?

I have not flashed firmware in a long time, and I am not going to do it now. Not when the software itself is running smoothly, and the problem is in hardware, and hopefully repairable. I am afraid of losing everything already installed on the device: cellwriter, Modrana, Firefox-for-mobile, et cetera....

As far as I have noticed, my N900 does not vibrate at all. When I restart it, I hear the Nokia's start-up tune, and that's it. However, I have never used vibration before, I turned it off in both Silent and General profiles, so it could be one of the reasons my device does not vibrate. In any case, vibrating non-stop should not be normal.

What are the shortcuts to determine what it happening inside the device? For instance, if the camera window is active, t will turn on/off the white LED, and h will turn on/off the red LED (http://wiki.maemo.org/Community_SSU/Features/Camera_UI). Ctrl + Shift + X should start X-Terminal; it definitely goes away from the camera window (camera shortcuts no longer work), but I cannot get "espeak cat" to pronounce anything (speakers are fine, I have heard incoming=missed calls). What could be happening?

Received my replacement flex cable today.

The good news: There's fresh adhesive on the back of the new cable.

The bad news: Looks like my N900 has more internal damage than I first thought. Needs more investigation.

But what's the problem? IIRC, this cable is detachable from both ends, quite easily.

Could You put some (good resolution and sharp, please!) photos of what exactly the troubling part is?

/Estel

There is no obvious defect that I could post photos of. The whole device got bent a little so that the screen unit jumped off its rails, ripping off the flex cable in the process, I guess.

The screen looks OK from both sides, but when I now switch the device on it stays completely black.

The vibration I reported above happens when I plug in the USB charger or attach the device to a computer. In the latter case I can access MyDocs just fine. I can only stop the vibration by removing the battery.

Switching the device on without USB cable attached doesn't show any obvious signs of life other than the indicator LED glowing white when pressing the power key, just as it should. (So at least the new cable is working properly. )

I'll try to attach a screen unit from another device and report back.

My last post was rather referring to Wikiwide's post about problems with replacing flex cable at all.

foobar, it's strange, that your device refuses to work OK after replacement. I can't imagine what else could be damaged by bending the screen module (unless screen itself was bend ) - other than metallic things keeping unit in place.

Testing with other screen module is good idea. Testing with other screen module *including* it's flex cable is even better one (which is what You probably want to do), as it wil leliminate damages to N900's PCB.

/Estel

My flex cable was sent by the seller, but I don't expect it to arrive any time soon.
I hope there will be fresh adhesive on the back of the new cable, too.
I hope that the internal damage of your device has not reached the core (processor, memory, camera) - just some cables disconnected?
First, to remove the whole flex cable, ten screws had to be unfastened. Eight of them had given way eventually, and the last two were literally drilled through (yes, drilled). The main flex ribbon can easily be disconnected from the keyboard part of the device - just one port. But the largest part of the cable is hidden inside the screen part of the device, glued by a white adhesive to the metal. Right now, there are no problems seen, just waiting for the new flex cable to arrive, hopefully with new adhesive on its back. And keeping the disassembled device away from water, dust and small children.
Second, the device was my primary telephone, camera, and all-in-one device. I have a more-than-ten-years-old phone which can be used, for now, as a replacement. But it doesn't have camera. And I miss my device, in general. I used to keep it under my pillow, my alarm, clock, torch, camera, audio-recorder, cellular-phone, GPS-map, C-coding and book-reading, Sketch-drawing and HTML-editing. I have installed speech-to-text once, and I have used text-to-speech sometimes; I have toyed with handwriting-recognizing-keyboard, and it was my dictionary and encyclopaedia.
What exactly the troubling part is... Look at the picture here:
http://goput.it/je9.jpg
The narrow long golden part of the cable hidden within the screen is in excellent condition (though fine sand managed to get even here, surprisingly). The wide black short part of the cable, connecting the screen to the keyboard, is cut at the root from the screen - only one-two millimetres are still sticking out while most of it remains attached to the port at the keyboard. If it was cut in half, it might have been possible to glue-solder it together, or find somebody who can do it - though unlikely, given the thinness and closely-spacedness of the wires.
That's too bad... In my case, the rails are fine, the time and reason of failure are clear, and the problem is failure of one detail, not of many pieces.
When you replaced the main flex ribbon, did you take care to reconnect the displays's cable to the port of the main ribbon? Just checking, I'm sure you haven't forgotten...
I'm not a vibration expert. If I was brave enough, I would have replaced vibrator motor with something else... But I'm afraid of doing anything permanent, irreversible.
Are you sure you have connected the new cable properly? Maybe, one part of it is connected, and allows LED to work, while another part is disconnected, and doesn't allow screen to work? Stupid idea, I know. Maybe, the back-light of the screen is not working properly, so even as the screen receives signals, it still remains black? My large computer had problems with screen's back-light some time ago, horizontal black stripes running across it randomly...
Thank you. I can hardly do anything until the new cable arrives, and foobar has more important/complex problems, so you are welcome to discuss them here.

I know how this cable looks, I've replaced it few times on some devices, actually don't worry,new replacement flex cables *always* contain adhesive part - it would be extremely stupid to sell them without it. Of course, it would be still possible to glue it on Your own, but still...

As for part about "part of cable connected OK and allow LED to work, but maybe other part is miss-connected and it's why screen doesn't work", it's not stupid at all. It might be the case for foobar - testing with another screen module, as he intent to do, will help to filter out possible roots of problem.

/Estel

by the way there is a very useful thread for using the n900 without touchscreen, but I can't find it now.

found it: http://talk.maemo.org/showthread.php?t=41389