Sad Mac 512k

#1 Sun, 22 Jan 2012 - 13:09 68kMLA

Ok so I know there's a fair amount of info on the net and on 68kmla regarding decoding the Sad Mac error codes however, I'm stuck...

I've a Mac 512k here which is in fairly average cosmetic condition and it starts up without chime and shows a Sad Mac with the number 02A000.

Any ideas what this code means? Interrupt does nothing and reset changes nothing.

xx(

#2 Sun, 22 Jan 2012 - 15:40 68kMLA

Suspect memory.

You may also have other issues relating to the video.

#3 Sun, 22 Jan 2012 - 23:31 68kMLA

judging by video corruption, video being in the main system RAM, id say RAM for sure.

#4 Mon, 23 Jan 2012 - 03:06 68kMLA

I'll check all the solder joints on the RAM.

Is it likely that one of the chips has just failed though? If so, is replacement even possible?

#5 Mon, 23 Jan 2012 - 07:02 68kMLA

It is certainly possible. You just have to desolder the old chip and install a new one.

#6 Mon, 23 Jan 2012 - 07:58 68kMLA

Although I'm definitely risking sounding like a "noob" here 8-o

Where might I be able to find a suitable donor chip?

And is there any way to determine which chip it may be from the code? Or is it a case of trial and error to narrow down which are faulty?

Perhaps I should check all the solder joints first....

#7 Mon, 23 Jan 2012 - 08:01 68kMLA

Oh and your website (and your collection) is awesome.

#8 Mon, 23 Jan 2012 - 13:26 68kMLA

octopart.com

#9 Mon, 23 Jan 2012 - 22:54 68kMLA

I've bought the DRAM chips from Jameco. As I recall, they are under $1 each.

#10 Tue, 24 Jan 2012 - 01:26 68kMLA

Excellent - thanks guys! Wish me good luck!