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billdeg
September 10th, 2007, 04:51 PM
I am getting a "sad MAC" 041800 error upon boot up

I understand that you break theses codes into class codes and subcodes. The first two characters in the code is the class code. 04 represents a "mod 3 test" memory errror (something I presume is wrong with RAM), but I cannot identify the meaning of the subcode "1800" - is this meaningless?

I have found sources on the web, but none pertain to this specific code. Or I am having trouble interpreting what I have found.

Please help! I am trying to identify the bad chip.

Bill

billdeg
September 13th, 2007, 05:05 PM
04 = class code = memory test mod 3
1800 = chip identification codes, in binary combination
1000 is bit 12, chip G9
0800 is bit 11, chip G8

..anyone have these for sale?

Druid6900
September 13th, 2007, 09:44 PM
I was running a bunch of memory chips through my chip tester the other day and I came across a number of 4264s but didn't test them because I was looking for 4464s (which tested good).

They aren't Apple, so, I don't know how important that is.

Just to be sure though, what are the specs you need and what is the chip layout? They are 41256 equivalents, aren't they?

billdeg
September 14th, 2007, 04:10 AM
I don't know, but I'd have to assume that they are the same thing. Probably you can use the 4464's too, but of the major manufacturers I am least experienced with Apples (but working to do something about it :-)

Interested in selling me a couple of tested 4264's? The old ones would need to be desoldered from the board / new ones re-soldered so I'd only want to do the job once. On the other hand I could install two sockets.

Bill

Druid6900
September 14th, 2007, 08:22 AM
Ok, what's this going into?

Give me the exact chip numbers and I'll do a little research and test up a couple of chips if they are the same ones.

Sell? No, but, if it turns out they will do the job, I'll give them to you.

Ya know what I would REALLY like to come across? Either a unit or a schematic for something that tests 16K x 1 DIP RAM. My tester doesn't go back that far.