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Classic II Black Screen


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Another repair, a Classic II, new caps all around, but except for the working fan the screen remained black and got no sound.

 

The board was cleaned but some goo was still present.

 

I removed the Egret 

 

post-1736-0-55583800-1493498860_thumb.jpg

 

Cleaned pads, soldered back and got a boot...only one  :-/

 

Then removed the nearby IC (U11), cleaned also legs then soldered back, and this time worked for real, including sound.

 

post-1736-0-49587000-1493499080_thumb.jpg

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  • 3 years later...
  • 68kMLA Supporter

@bibilit Thanks a lot for this post!

 

My long-owned Classic II suddenly, just a day after using it without issues, exhibited the same symptoms. No sound, completely black CRT, voltages measured on the floppy port all correct. That was really sad - it's my first compact mac and I really wanted it up and running again.

 

I have recapped this machine a year ago and washed the logic board really, really thoroughly (water + IPA).

 

As it turned out, desoldering EGRET (U10) and U11 with hot gun revealed quite a bit of sticky goo under them. No traces were eaten, but the goo was probably shorting some pads/vias. After thorough cleaning (the PCB and the chips), bathing the chips themselves in IPA and resoldering all is good again! :) Thanks for this hint!

 

TL;DR Even after thorough washing, cap goo stays under U10/U11 and prevents the machine from booting. Desolder the chips and clean everything.

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Yes, i have seen this issue too often, Classic II and CC are affected a lot (probably pretty close from the surrounding capacitors) in my opinion even a thorough cleaning is unable to solve the issue (or maybe probably using a ultrasonic process)

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