Macintosh 128k problems

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Joined: Jul 13 2011
Posts: 5

Heeeeelp!!!!!! Strange black lines partially blocking sadmac!!!!
When I first got it, there was a sadmac with the error code 048545
I then proceeded to remove the ram chips and installed ic sockets.
I must have messed something else up because after replacing all the ram chips
This is the screen that appeared:
http://www.flickr.com/photos/66677313@N05/6071632219/
I've checked the continuity between all the ram chips. All my solder joints are good
I then changed the ROM chips with known functioning ones. Still no luck
Anyone have any suggestions????
Thanks...

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Fabien

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cwsmith's picture
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Joined: Oct 13 2005
Posts: 699
Re: Macintosh 128k problems

While inside, did you check all capacitors for swelling or leaks?

Could also be a bad power/sweep board. (controls AC in, and horiz/vert resolution)

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Joined: Jul 13 2011
Posts: 5
Re: Macintosh 128k problems

I'm actually testing the board in a working machine, so I know it works.
The capacitors are very few in this model but I might as well replace them anyway just to be sure,
However at a visual inspection there's no electrolytic fluid around them

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Fabien

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Joined: Aug 3 2011
Posts: 33
Re: Macintosh 128k problems

Is the pattern of the black stripes consistent?

Try swapping the RAMs around, maybe.

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Joined: Jul 13 2011
Posts: 5
Re: Macintosh 128k problems

I've done that and It's the same.
When I desoldered the ram chips I used a heat gun.
maybe I overheated resistors or capacitors or other chips

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Fabien

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Joined: Jul 13 2011
Posts: 5
Re: Macintosh 128k problems

Still no results I guess I'll start replacing parts one at a time until I figure it out.
Input greatly appreciated...

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Fabien

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Joined: Jul 13 2011
Posts: 5
Re: Macintosh 128k problems

So I just ordered a copy of the dead Mac scrolls hopefully there's something in there so far it's a total mind bender
Does anyone have any more thoughts?

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Fabien