Sad Mac 512k

[macman142]

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(

 

[Mk.558]

Suspect memory.

You may also have other issues relating to the video.

 

[techknight]

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

 

[macman142]

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?

 

[mcdermd]

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

 

[macman142]

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....

 

[macman142]

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

 

[Bunsen]

octopart.com

 

[mcdermd]

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

 

[macman142]

Excellent - thanks guys! Wish me good luck!