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Caps! -- Macintosh Portable /w backlight (BL-INVERTER BOARD)

Posted by: uniserver on 2013-03-02 22:33:13 I did not take pictures of the inverter board that is sitting right next to the LCD screen. However, before i got my 6v 5ah Lead Acid battery rebuilt, I was monkeying around with the portable using a Powerbook 1x brick to run it. The back-light ended up going out on me... I was quite sad by this. Ended up rebuilding my battery, and then taking apart the screen to have a look at the inverter. I found 2 little radial 16v 10uf caps, basically i soldered tantalum caps on the back side of the PCB right to the bottoms of the cap leads, then clipped the caps off from the top. put it all back together and voilà the back-light now works. Here are a couple pictures, next project, dreaded HD conversion 🙁

Posted by: shred on 2013-03-03 01:50:21 The hard disk conversion in a Mac Portable (I assume you intend to use CompactFlash) is fiddly, but well worth it. I found that the original Conner hard disk was very noisy, but now the only noise is the whine from the backlight inverter and the battery life is better too.

Posted by: Macdrone on 2013-03-03 01:56:06 Told you there were caps on that board 🙂

Posted by: uniserver on 2013-03-03 08:39:20 Originally, I didn't want to change the caps because they were not leaking. also the display cable had developed a crack right were the cable leaves the screen off to the LB. I could see there was a thick trace, that was right on the edge were the crack was, just to be sure i ran a wire wrap line all the way from the display connector to the inverter connector, I doubt that was what fixed it. Sometimes when you get into a project you see many other things that need attention as well.

Posted by: Macdrone on 2013-03-03 11:33:21 Ya im looking for a backlit no luck yet.

Posted by: SpectreGadget on 2013-03-28 19:11:13 Thanks to uniserver, my 5126 is working like a champ. But... the backlighting stopped working after powering it up for the first time with the new caps, so I suspect a similar problem. I will give a shot at replacing the two caps on the inverter and see if that fixes it up. Fry's has http://www.frys.com/product/1710689, which look like they'd work. Yes?

Posted by: uniserver on 2013-03-28 20:39:22 Yes I would like to say those should work. also, make sure to check the monitor cable for cracks. Make sure you are running your portable with a battery in it. Running your portable with out a battery is like starting your car, then removing the battery and making it run solely off the alternator. yeah it will do it... but you are really really asking for trouble.

Posted by: uniserver on 2013-05-26 21:23:43 ok, I had another strange issue with the ( back - light ) in a Back-lit portable. The back light worked, and then it stopped working. The board and screen were sent to me as a set, it needed a re-cap, and the back light was out. so i re-capped it. Checked the display cable, the display cable looked great, Changed the caps on the inverter card anyways. I even ran new (-/+) power lines to the inverter board any ways... still no back light. I checked power to the inverter, .63v I thought that was odd So i pulled the main-board out, I do remember wrestling with some radial caps that were very leaky, and really corroded. These two! Looking closely, it appeared no solder had flowed through the hole to the top. Normally you can see a little solder muffin top, where the solder comes up from the bottom. In this case both were dry. So I pulled those 2 caps out and used my wick and a bunch of flux and got those 4 holes cleaned up. poped those caps back in , soldered them in, and now all is working nicely.

Posted by: uniserver on 2013-12-19 19:20:05 i just did this one for hap. the video cable was really shot, from flexing, it was cracked, and shorting. so i hard to use my little side cutter and cut that hunk out of the cable. luckily the LCD data part was not damaged just the back light section. it was a beast, i had to run all new wires to the inverter by hand one by one, from the header. but it works now, so that is good. I reinforced the cable where the break was with goop, so should be a permanent fix.

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