Macintosh Portable Power Issues

[zuctronic]

So I recently acquired a Mac Portable. As soon as it arrived I took it apart, re-capped the motherboard and hooked it up to a replacement battery. Everything was going well, actually no issue at all last night. I was able to mount some Appletalk volumes and play some games, it seemed pretty stable.

This morning I decided to break open the original apple battery and toss my new cell in there. While testing this configuration, I accidentally hooked up the battery with reversed polarity... I know, this was dumb.

Now I'm having issues again. Here are the symptoms:

1. Will not power on at all without wall charger plugged in.

2. Randomly crashes when doing anything.

3. It will go to sleep, but when it wakes up it either crashes with a crash chime or it just reboots.

4. System 6 "battery" meter shows battery slightly above middle charge all the time now (I doubt its accuracy!)

5. When I try to change the date, the system crashes / reboots.

Any ideas? Could it be just a fuse? Is there an easy way to troubleshoot this without a meter?

Thanks in advance! I hope I can get this back to life again...

 

[zuctronic]

It was the motherboard fuse F1. Whew!

 

[jmpintof]

Hi @zuctronic

This message may arrive a bit late to your first post, but I was intrigued by how you got to fix this issue.

I made a similar mistake, but instead of hooking up the main battery with reverse polarity, I did so with the little 9V battery .

I just got this machine, got some replacements it needed and I was near finishing when I realized this fatal(?) error happened.

In my case, I started with a nonworking machine, so there might be other issues. In fact, I detected no continuity in a capacitor.

When you say you replaced fuse F1 you mean this yellow cylinder (that's the only F1 I saw on the logic board)? (see picture). In my case there's continuity, so my first impression is that this guy wouldn't be the culprit...

Any comment will be valuable to troubleshooting this, thank you in advance, and hope you get this message.

 

[zuctronic]

Yes, that is the fuse I needed to replace. If it has continuity, it's probably fine. If you haven't replaced those capacitors around the hybrid IC (C7, C15-16, C24-28, etc) then you need to, 99% certain. Also I'd avoid giving this motherboard any power at all until you've replaced those capacitors or you risk doing damage to the hybrid IC, which is irreplaceable at present.