68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Help Color Classic - Won't Power On
Posted by: krimstah on 2019-05-20 03:15:42
Hi All,

I recently acquired a color classic from a seller, Originally the computer was not booting so i recapped the motherboard and it came to life. about a week later the computer would not boot from the hard drive and now it will not boot at all. (No LED or anything)I have left it plugged in the wall for 24 hours and tried again but still no sign of life.

I have pulled it apart and inpected the analogue board but can not see any bulging capacitors but there was alot of dust. Can dust short these out and make them unusable?

Please help

3pdbbnuazhw21.jpg
Posted by: EvilCapitalist on 2019-05-20 04:53:45
First question is if you remove the motherboard and flick the power switch does the machine sound like its trying to start up (fan turns on, screen degausses, hard drive starts)?  I have had CC analog boards that packed up with no outward signs of trouble.
Posted by: krimstah on 2019-05-21 03:53:45
First question is if you remove the motherboard and flick the power switch does the machine sound like its trying to start up (fan turns on, screen degausses, hard drive starts)?  I have had CC analog boards that packed up with no outward signs of trouble.
Hi  EvilCapitalist,

You are correct the CC does the above when removing the logic board. I have attached photos of my logic board if that helps

IMG_1071.jpg

IMG_1072.jpg

IMG_1073.jpg

IMG_1074.jpg

IMG_1075.jpg

IMG_1076.jpg
Posted by: EvilCapitalist on 2019-05-21 05:29:30
I don't suppose you've got another board you could test in that machine?

The next things to check would be seeing if there are any broken traces on the motherboard, but tracing continuity and seeing if any of the chips that are known to fail on these boards have given up the ghost is a bit above my skillset.  When you recapped the board did you wash it first?  I know with my machines the old caps left gunk *everywhere* and when they were being recapped the person doing the work said several of them had more problems than just bad caps.
1