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NC200 Display Error

Started by logiker, 15:49, 23 March 19

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logiker

Hi!


The display of my NC200 shows "empty lines" on the top.
I wanted to check the hardware of the display, but couldn't get through.
Can anyone help me to open this part of the machine?
Any disassembly instructions or manuals etc.?


Thank you


Logiker

ps:
The second pic shows, where the resistance seems to be.

GUNHED

My NC200 has exactly the same problem. And couldn't fix it.


Maybe this can help...

https://www.youtube.com/watch?v=0w8n-8mga5E

http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

logiker

Quote from: GUNHED on 16:32, 24 March 19
My NC200 has exactly the same problem. And couldn't fix it.


What did you try in order to fix it? Could you open the monitor part with the LCD display in it?
I assume there is some screws so I can't open it.
I just wonder if it's worth to go further or not.


I saw the video already. As far I went through it, he doesn't open the screen and I don't understand that much French, so it was of no help, unfortunately.

GUNHED

Ich wollte die Kiste nicht kaputt machen, also hab ich noch nicht damit angefangen, aber eines Tages komm ich nicht darum herum.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

logiker

Ja, eine traurige Geschichte mit underen beiden NC200, in diesem Fall.
Vielleicht meldet sich ja noch wer.

TynH

My money would be on the ribbon cable being the culprit.


Have look here for disassembly (better download before Google+ shutdown):


https://plus.google.com/photos/100438501927183409615/album/6092017202389272641?sqid=105970345075021822765&ssid=97b1b51a-0e61-40e3-a42d-a5af10d95810



GUNHED

#6
Naja, wenn man am Bildschirm seitlich des Bildschirmrandes hindrückt, dann wirds kurzzeitig etwas besser.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

logiker

Quote from: TynH on 17:57, 24 March 19
My money would be on the ribbon cable being the culprit.
Have look here for disassembly (better download before Google+ shutdown):


Thanks 1000 times! That's what I needed and it confirms what I thought.
The screws are hidden below the "lable" thing.


Any hint how to get the lable off easily without destroying it?

robcfg

I use lighter fuel to separate the labels without damaging them.

Bryce

It's usually the zebra strip (the part that connects the glass to the PCB) that fails when these type of failures happen. This is relatively easy to fix if you can get to it. I don't think I've ever tried to open the screen of my NC200, so I have no hints on getting in there.


Bryce.

logiker

Thanks for the info Bryce.
I fear a bit, that the LCD display is already kinda too old as the brightness has to be set to very low so I can see anything at all.

Bryce

That's usually happens when the capacitors are starting to fail. If you like you can send it to me and I'll re-cap it and fix the zebra strip.

Bryce.

logiker

Quote from: Bryce on 13:37, 25 March 19
If you like you can send it to me and I'll re-cap it and fix the zebra strip.


That would be awsom! I'll pm you.

Bryce

@logiker : Ok, so here's how it looks... Unfortunately, the NC200 doesn't use zebra stripes, it uses a crap method that was attempted in the 90's and is no longer used because it was so unreliable (Red boxes are the vertical connections). On top of that, the horizontal connection is on a PCB that's soldered into place (Blue box with connections on the other side).

So the options are: Leave it as it is and live with the stripes or do an "All or nothing repair". This means removing that PCB on the right, giving it the hot-air treatment, soldering it all back up and hope for the best. This could work, but it could also result in even more stripes across the screen. I've seen more skilled people than myself mess this up, so I'll leave it up to you...

Bryce.


Bryce

Soo... Unfortunately the problem turned out to be cracks in the flat cable, not bad solder joints. Unfortunately this is something that can't be fixed without a new screen (the flat cable is bonded to the LCD glass) :(

Bryce.

Bryce

For completion, here's a picture of the problem under the microscope. For anyone else who encounters this problem, it's not repairable. The cracked traces are carbon-silver, the same stuff used to make keyboard membranes, not copper. They are glued to the PCB and in some cases the glue has just weakened and can be re-glued (heat with a hair-drier and push the contacts). However, in the NC200 there is enough relative movement for them to crack and nothing is going to repair this. You can see the crack running between the two red arrows, this is the wider band that is missing from the top of the display. Unfortunate.


Bryce.


logiker

Although it's really sad news, I think this information might help many people who own or are interested into a NC200.
Thank you Bryce!


Logiker

Gryzor

Ooh I've seen this type of connector before (LCD game I think?) and I remember automatically classifying it under "never in a million years". So, when do these cracks appear? Is it age or something else?

Bryce

Forget the NC200, what just happened to the Forum? Or am I accessing it via a mirror site :D

Bryce.



Gryzor

I think your ribbon connector must be connected upside down?

Bryce

But back to the NC200: It's a mixture of a very questionable and fragile design, paired with the fact that plastics loose their elastomers over time and turn brittle.

Bryce.

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