128k Sad Mac Error Code 040200

[JDW]

I tested out one of the 128k boards in my collection for the first time today:




Unfortunately, I get a Sad Mac Error Code 040200 at cold boot:

I never tested this board because it came with a 512k board when I purchased it, and the 512k board always worked and gave me more RAM to boot. Not sure if the previous owned upgraded to the 512k for the RAM only or because his previous 128k board had problems. In any case, I do see that at least 2 of the 3 axial electrolytic capacitors on the board have leaked. What are your thoughts?

Thanks.

 

[techknight]

could be anything. But because of the picture artifacts that come and go, I am betting on RAM, as those artifacts are landing within the address locations of the framebuffer, be it RAM itself or the A/D lines between RAM and display.

 

[JDW]

So you would not rule out bad influences from leaked capacitor fluid then?

 

[techknight]

only if there is evidence of it. Meaning, you can physically see corroded traces, and if you follow a schematic and test point to point between RAM and its logic.

if thats ok, then no its not the electrolyte. Be honest, i dont think I have found any cases in my personal experience that capacitors have "killed" a board. Sure, they have done lots of damage, but unless its VERY severe, the electrical connections still remained intact. Now batteries on the other hand, yea.......

Besides If I am not mistaken, the axial capacitors are only in the power plane.

But all in all, since the capacitors have leaked and me not physically being able to see the board, no i cannot entirely rule that out, but judging by your picture, the capacitor hasnt leaked enough to do any damage at all. Axials typically do not.

 

[JDW]

I see a bit of green gunk at the point where the leads exist the body of the axials -- always a sign of leakage. Furthermore, I was brushing dust on the board away with a small paintbrush when I noticed that I was starting to paint with a clear liquid. But I did not spot any eaten traces.

Assuming the 040200 Sad Mac Code is RAM related, does that code point us to a specific chip on the board?

 

[gubbish]

Here's the table of Sad Mac codes:

http://support.apple.com/kb/TA46376

Looks like 040200 translates to bad RAM at location G6.