Monitor troubles

[milihpen]

Ok, so over the weekend, I dissassembled my monitor, a 17" 1702fp (Dell). It all went well, I grounded myself, and neither heard nor felt any sparks or tears in FFC cables. Once I had it mounted in my frame, and turned it on, however, I was sad to see that...well, it was "messing up."

The screen showed a block of whitish pixels spanning from the top to bottom of the screen, about 1/4 the width of the whole panel, slowly moving from side to side. Also, the lcd monitor seemed to be making a very slight humming noise (this might be natural, though, I don't know?), coming from either the board on the bottom of the screen or the screen itself.

I have a feeling that the problem is my ffc cable: i had to extend it, and I may have flexed it too much, killing some wires or something. Also, and I know this probably wasn't the smartest thing to do, if I moved the cable slightly when the monitor was on, horizontal lines appeared in the picture.

So this is my guess: the contacts on the ffc are messed up: either on the end connecting to my extender, on the end connecting to the side board, or somewhere in between. This is my guess, as the image that showed look like an image stripped of the vertical( side resolution): the width of the white section appears to match the width of the Dell "No signal found" box, and when I moved the ffc, vertical lines appeared (giving me the hope that these lines, if I fixed the problem, would represent the vertical(side) resolution).

So, tommorrow, I'm gonna check that out: I'll (gasp) totally dissassemble my frame, and look at where the ffc connects to the side controller panel. My question is , if I find that it's party unsoldered, is it easy to solder it back? There're only 20 pins, but that's quite a lot for soldering, not to mention the fact that I shake a little.

My other question is, why is my panel making a noise? It's slightly humming, and it seems to do it only when the image appears on the screen( in other words, when the monitor is not showing the "no signal found" dialog box that is stretched infinitely vertically, there is no noise, and when the "image" appears, there is a noise. Is this normal? I don't know. If it isn't, what do you guys think the problem could be.

Thanks a lot for your help, guys. With any luck, my panel isn't totally dead. I'm now pretty sure that I didn't damage any of the REALLY thin little cables connecting directly to the lcd, but either I somehow fried some circuitry responsible for the vertical resolution, or my ffc cable on the side is faulty (probably due to too much flexing or something). Anyways, thanks again.

[Stocker]

did you break any ground connections? try jumpers from PCB to PCB or PCB to power supply ground, connecting any obvious "earth" connections.

[milihpen]

thanks for the tip. I'll try to do so, and see if it works. Would that be causing the weird block of pixels, though? Without the vertical resolution?

[Stocker]

crazier things have happened in digital systems when the ground is no good.

[milihpen]

Eureka!

Stocker, I owe you so much. I did as you said, and grounded the boards. I was doubtful that this would solve it, but when I turned the monitor on, the noise I described was nonexistant (actually, there, but only slightly audible with my ear an inch away from the controller board...you think this could be a problem? I dunno), and to my absolute delight, the Dell Self-Diagnostic test image came bouncing around my screen. I swear the image is upside down, but maybe I just lost my orientation when mounting the lcd.

One note, I didn't ground the board connected to the lcd on the bottom. I didn't know if that would do any good, as the mounting holes for that board were plated? in gold?, without touching any other components, so I figured I'd try it this way first. Here is a picture of the board I'm talking about, thanks to Superdaveumo (I have the same monitor he does) :

http://img522.imageshack.us/my.php?i...ameback2np.jpg

see the gold contacts? I don't know if those should be grounded.


Anyways, thanks so much for your help, Stocker. You saved me a couple of hours of dissassembling and fiddling with my monitor, and possibly (and probably) buying a new one after I messed it all up. Thank you so much