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Patater

A Naked and Nasty Macintosh Portable

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I took apart my Macintosh Portable this evening to make a count of the different capacitors I'll be needing to replace as part of the standard "holy crap this is old I need to replace the caps" operation. I updated the capacitor replacement wiki page with my findings. To my surprise, I discovered that this Macintosh Portable has the nastiest case of electrolytic corrosion I've ever seen on a logic board. I know some people on this forum want to know what leaking electrolyte's effects look like; and boy do I have a treat for them.

 

Naked Pics

macportable_logicboard.jpgmacportable_logicboard_2.jpg

 

Nasty Pics

macportable_capcorrosion_1.jpgmacportable_capcorrosion_2.jpgmacportable_capcorrosion_3.jpg

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I finally got my tools in order and took the time to do some work on this smoking hot babe today.

 

First off, I removed all the nasty caps with my new diagonal cutters. Some of them very easily came off from the PCB all on their own. Others I tugged at a little bit. Some left leads behind that I later had to desolder; the best way to desolder these seems to be to clean them, flux them, head up the lead only (not the corroded solder), and push on it a bit. Sometimes, you can find a bit of shiny late 1980s solder under these leads. The leads that came out with no problem had corrosion even within the footprint of the removed lead.

pcb_cleaning-trash.jpgpcb_cleaning-caps_removed.jpg

 

To clean the board after removing the capacitors, I used 91% isopropyl alcohol (although I'd prefer 99%), a non-abrasive lint-free wipe, and a small brush. I'm still waiting for a horsehair brush, so I used one of those disposable (pre-pasted) toothbrushes instead of what I'd have preferred to use. I splashed a bit of alcohol onto my wipe and proceeded to rub the PCB through the wipe. Most of the crumbly brown and white stuff came off the board with the alcohol and brushing.

pcb_cleaning-alcohol_tools.jpgpcb_cleaning-after_alcohol.jpgpcb_cleaning-dirty_wipe.jpg

 

Even after the alcohol, she wasn't looking so good yet. It was time for the flux. I applied flux with a Kester #951 ("no clean", but I clean it anyway) flux pen. Then I heated up the pad with a 750 degrees Fahrenheit iron tip, to try and melt what solder was there. I could often push the surface corrosion away from the solder after I got into it. While the pad was hot, I applied fresh new solder and left a nice wet hump of solder on the pad. I got out my solder wick and wicked the hump away, while at the same time taking advantage of the oft maligned property of solder wick: that it is abrasive. With a few (2 or 3) swipes of the solder wick, the pad became much cleaner. To get things really pretty, I applied flux again, put down more solder, wicked it away, and then cleaned with alcohol (in the same manner as before). With the exception of a few light scratches, the pads looked pretty much new. They'll be much easier to work with and much more receptive of new parts now.

pcb_cleaning-after_patater.jpg

 

She is looking quite a bit better after this work, as you have seen. Her pads are shiny and fresh. The next step is putting on some nice new orange tantalum capacitors.

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you can also use a solder saturated wick to hot mop the area, its a bit less wasteful and abit less time consuming although your going to have to clean up a ton o flux

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Thanks to Trag whose handy capacitor kits make it easy to get into fixing up these boards. If it weren't for him, my portables would still be sitting dead in the closet. :beige:

 

When I finished recapping my first portable, I took a picture in case I needed it to document the procedure, and looking at the pic in iPhoto, discovered I'd missed one capacitor. Wuups!

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Yes, trag's caps are great. I need to get some more from him. I am missing one capacitor in order to complete the replacement on my SE/30. I am also missing one capacitor in order to complete the replacement on my LC III. I was hoping to finish the SE/30 this weekend, but it looks like I'll have to wait until I can get my capacitor fix from trag again.

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Hi Everyone

 

I've just rebuilt about 12 of my Mac Portable's however I had one issue, when I replaced my some of my portables SMD caps with Tantalums, well 3 of them caught fire! :disapprove:

 

This happened on the Non backlit and Backlit model.

 

I used the correct rating on the tantalums, I dont quite get why this occured, I do not completely understand how the technology differes between the SMD caps and tantalums, I always assumed the ratings are the same it was all good.. But apparently not.

 

Not sure if it has to do with the fact I am using a 7.5v 3.0a power adaptor for my test runs, but either way, can anyone suggest why such a thing would occur? After scorching two boards pretty severely now I am concerned with the tantalum re-build of the Mac Portable...

 

Could it also have to do with other ageing componentry?

 

Any thought would be welcomed...

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Actually i think i know why.. It seems I installed the all the wrong way around... ARG!

 

Why is the painted stripe on SMD caps negative, but positive on tantalums!

 

GO FIGURE!@

 

WOOPS!

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If you installed any backwards, that is exactly the problem.

 

You have a lot of Portables. What do you do with them all? Do they all have batteries that work?

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No, they don't all have working batteries.. yet.

 

I have a whole stack of macs, I have been collecting them for years, due to the fact many that I bought had varying problems with diskette boot, drives, lcds, bad backlits, leaking caps, board damage etc.

 

Thankfully my Mac Portable skills have grown significantly, now having retrofitted the caps, cleaned up the damage and corrected damaged tracks, rebuilt batteries, rewired damaged cables, restored plastics etc, so I've now got many working units that were purchased over the years as bad or damaged.

 

Yes, makes complete sense why they burned up. I just can't believe how stupid I am... I never even thought to check, I made an assumption.. a bad one at that.

 

Thankfully the burned up components didn't damaged anything more then superficially.

 

What to do with um all my mac portables.. I have no idea now. I've gone from having about 5 flakey and 1 solid machine to 12 solid and 6 "to hard basket to be worked on later" machines.

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I had two dead Portable batteries. I wanted to re-cell them, so I attempted opening one with a screwdriver, but that totally messed up and and bent the plastic. I have one remaining, but I don't know how to open it cleanly in order to install new cells. I'd appreciate any advice you could give on rebuilding the Portable's battery.

 

I acquired a flaky Portable in 2003. It would often crash or sad mac, but it could boot and do stuff more often than not. When I tried to play with it again around February of 2010, I found that my PowerBook 100 adapter had failed (by no longer outputting any current; i.e. as soon as a load is present, the voltage goes to zero). I replaced all the capacitors and hooked up an alternate battery, but currently all I can get out of it is a sad mac. Your battery opening advice might also help me to open and fix my power adapter.

 

My goal for this Portable is to get it running solid with a good battery and a good power adapter so that I can do software development on it. I am reading Inside Macintosh now to prepare for this. Eventually, I'd like to boost its RAM to the max, and that will probably involve creating new hardware.

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I had success repairing two of my mac portables with Sad Macs after lengthy board repairs.

 

As for opening the batteries, its been quite some time since I opened one, I used a box cutter at a 45 degree angle to score the join in the plastic from memory (as deep as i could) then in fact bashed the corner to force it to crack open. This had the side effect of a chip in the plastic.

 

The alternative considering you are in the USA is to get Ni-Cad lady to rebuild them for you

 

I dont know what her charge is, but I got a couple from there about 3 years ago and they are still working now, even thou I poorly treated them.

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