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mrpippy

PowerBook 2400c backlight but no video

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A couple years ago I bought a PB 2400c on CL that turned out to have a cracked screen (but otherwise working great). Then last summer on eBay, I bought a PB 2400c display (including hinges/lid) which was untested but at least isn't cracked. Finally got around to putting the screen in, the machine boots, backlight lights up but no picture. I guess the next step is to open up the displays and swap the flex cable from the cracked screen to the good one. Has anyone done this, or had this problem before?

 

 

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Does the backlight on the cracked LCD work when this is plugged in? If so, swap the inverter/controller board from your cracked LCD 

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Yeah the cracked LCD otherwise works great, backlight lights up, and in the very corner you can see the cursor/control strip. The picture in the thread I linked shows the control board, I don't know how I could swap that between panels.

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The controller board is and can be removed once you work out how it is attached - possibly by glue, tape and small screws.

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I swapped the flex cable and inverter/button board between the displays, same result, no image :(

 

I looked closer at the driver board, the problem is the FFC/FPC ribbons attached at the bottom of the driver board that connect to the panel itself. I think the ribbons are soldered onto the board using a "hot bar" which applies pressure to the whole width of the ribbon and then heats it to solder. Might be glue involved too (sometimes they use a conductive adhesive). I have a hot air station so I could probably get them off, but re-soldering them (reliably) with a regular iron just does not seem possible. Especially since the pads aren't even visible.

 

https://www.crystalfontz.com/blog/faq-hot-bar-soldering-for-tab-cof-style-modules/

 

 

IMG_8324.jpg

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before you go crazy. Check the little pico fuse next to the connector. Bet its open. Change it. 

 

Edit: I see it in the top right corner of your picture, and I can see that its burned open. Theres your problem. 

Edited by techknight

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I hate to resurrect an old thread....but I had the same problem previously with one 2400c I had imported. As it turned out, a surface mounted fuse on the logic board was the issue. I tested the fuse for continuity, and, after confirming no life, bypassed it to end up with a booting unit. Bought a strip of SMD 2amp fuses on eBay, and the rest is history. Prior to that, the screen would just light up, but system would not boot. The fuse that caused this issue, in my situation, was located on the center of the logic board. 

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I know, the thread is old... But if someone still need an PowerBook 2400c Display or other parts - let me know. I"m thinking in disassemble my 2nd PowerBook 2400c to keep some parts as spare and sell some.

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