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Macintosh II: coincidence in corroded traces?
Posted by: Macbuk on 2019-04-01 03:02:56
Yesterday i was playing with some non functional boards i put in a box over a decade ago. 

SAVE_20190401_100544.jpeg

[SIZE=14.4px]Of them, the one i recapped in 2008 has been suffering from erratical no video/no nubus syndrome. The[/SIZE] reflowing of colder joints and the recostruction of one lifted pad restored the board to a functional state. 

Strangely i have found an irregular corroded or scratched trace[SIZE=14.4px] starting from memory slot. It was corroded exactly above the "C7" capacitor writing.  I've[/SIZE][SIZE=14.4px]'v[/SIZE]e found very similar pattern in a second, not yet restored, board and even in a IIx (!!!) Why only one and why the same ?

SAVE_20190401_100604.jpeg

SAVE_20190401_100554.jpeg

 
[SIZE=14.4px]Any insight? Could be because of Apple intervention during test phase or in the support timeframe?[/SIZE]
 
[SIZE=14.4px]Or are them simply badly corroded traces because of C7/battery acid leak?[/SIZE]
Posted by: olePigeon on 2019-04-01 08:19:18
My guess is badly corroded traces from the capacitor leaking.
Posted by: LaPorta on 2019-04-01 14:49:12
I had a similar issue and bypassedit with a very thin wire run under the board.
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