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PowerBook 3400c upgrades & Preventative Maintenance - A question or two.


Well-known member
Recap SUCCESS! Just got the chime and blinking question mark after replacing every last electrolytic in the entire system. I’ll have a full writeup and reference info up on a separate thread soon.

Edit: there is a strange display problem now that wasn’t there before.
That weird smudge looking thing definitely wasn’t there before. It’s not where the caps were so it definitely isn’t damage from the soldering iron. I also don’t see how it could be an internal fingerprint on the backlight diffuser as I didn’t take it apart far enough to cause that.
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Well-known member
Phew, good news. The smudge seems to be going away on its own for whatever reason. I can only see it extremely faintly when the display is off now, and it is pretty much invisible when on. I was really worried about that so I'm really pleased that it has seemingly solved itself.


Well-known member
Everything is all done now, and the laptop still works!
Look at all of that free space!
I‘ve chosen to do an absolutely ridiculous quad-boot of Mac OS 7.6.1, 8.1, 8.5, and 9.1. Each OS is put on a separate 3GB partition, with the remainder being put into one huge data partition for all of my software. It’s running great like this! The recapping went fine, which I’m really happy about, and I was able to mend the one standoff that broke during disassembly with the plastic weld stuff. I also applied it around the hinge standoffs, I don’t know if that will actually strengthen them or not but it can’t hurt them.

The only issues are as follows:
1. The smudge isn‘t fully gone. You can’t see it head on (which is good), but it does partially appear at extreme viewing angles. My only guess is that I somehow caused a bit of pressure damage, although I’ve got no idea how.
2. The speakers sometime crackle a bit during startup. Occasionally, the boot chime will sound distorted, and I will hear a bit of crackling now and then during the boot. After that sound works 100% fine with no distortion. Strangely, this seems to happen the most when I boot 7.6.1. My only guess is that it’s something to do with what caps I used as replacements, but I’m also not sure whether it’s the main speakers, the display woofers, or both. It doesn’t affect use though, and again, sound works fine after that. I also haven’t tested to see if this happens from the headphone jack, mainly because it only happens every now and then, and not on every boot.

All in all, I’m glad I went through all of this work. It’s now going to be more reliable, faster, and hopefully the hinges will hold up better too. The best part is that I don’t have to wait for the hard drive to spin up after it has been idle for a few minutes, now it’s instant!