Macintosh Portable M5126 - Battery problem - Good night :0)

Scouter3D

New Tinkerer
Aug 4, 2026
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0
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Hi,
my name is Tom and this is my first post in this forum. I run a small online homecomputermuseum site and i repair a lot of vintage computers.

Now, i am in the process of fixing a non working Macintosh Portable M5126 for a friend

After recapping and fixing 3 broken traces / Vias the mac greets me with a chime and boots a systemdisk from the diskdrive.

BUT: then i get the "no reserve battery power - good night" message imediatly after the system is bootet.

BTW: the battery is a new replacement one and gets charged from the mac and meassures around 6V, but the mac battery menuitem shows battery level at 0%
the small battery compartment switch is working and both buttons (reset and inerrupt) are working.

Without the powersupply the mac does not startup at all / or only 1 second...

Yes, it is possible that there are more bad VIAs

It would be great if someone could give me a hint where to search, or what to meassure (i can use my oscilloscope) ... to narrow down the search-area :0)

Cheers and many thanks in advance, TOM:0)
PS: Sorry for spelling mistakes, as my native tounge is german (i am from austria)

PSPS: is there a correct schematic for the M5126 somewhere?

mp_bigger.jpg