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Macintosh Portable Backlit Screen Stripes


Well-known member
Hello there!

I need some help here. Maybe @techknight can give me a hand, as I have read some of your posts here about this model. I bought this Portable from ebay that won't do anything at all. I bought it recapped and with new mosfets in Q1, Q15, Q16 and Q20. At first I though it was a power related problem because I didn't get 5V anywhere nor 12V on the 12V line. So I also replaced Volt Reg, OP-AMP and VR1. It gave me no results so I kept digging and I found open vias in transistor Q18 and capacitor C9 (see pictures). I don't intend to leave it this way, but it makes good contact, so it's OK for now. Since then the Macintosh starts when a key is pressed, no startup chime, no hard disk spin (no 5V on HDD line) and background noise on the speaker. "Restarts" when reset button is pressed and shuts down when both buttons pressed. NMI power alone does nothing.

Only once I got the sad mac message in the picture with code 00000000 - 00000068. I could find any meaning to this.

I have done as described in this thread:

-First: power. Good shape battery, tried with power adapter and with external power source connected to battery bay. Same result.

-Second: replaced 74AC02, 74AC10 and 74AC157.

-Third: checked reset and NMI buttons. Both are 9.9kOhms.

I couldn't find any other open vias or anything, so I would appreciate any tip or idea about what to do next.

I wasn't able to post any pictures or videos here, I got error -200. Tried from a different computer with same result. I link pics on Google Drive, I'm sorry :(


Thank you very much!



Well-known member
@GregorHouse Sorry for digging this out, I have a very similar problem with a backlit Portable - have you found out anything more about this machine? Thanks!