Jump to content

Macintosh Classic Sad Mac RAM expansion error


Recommended Posts

Morning all,

 

I've tried a few searches on this site and on Google directly, but I can't seem to find a reference for Sad Mac error codes for the Macintosh Classic. For the SE and Plus yes, but not the classic directly. Or, perhaps I have misinterpreted what I was reading and maybe just need to have someone nudge me in the right direction? I have one Classic that will boot fine without the RAM expansion installed. With the RAM expansion installed I get a Sad Mac with the following code:

 

00000005

00100000

 

Following this document here: https://udcf.gla.ac.uk/~gwm1h/Error_Codes/Sad_Mac_Codes.html

It says: "$05    - RAM external addressing test failed. Minor error code indicates a failed address line." which follows that this only happens when the RAM expansion is in. The lower numbers should be the address line that I should be checking.  But how do I translate 00100000 into a trace on the motherboard that I should be checking for continuity? 

 

Any advice would be welcome. Thanks in advance.

Link to post
Share on other sites
  • 1 month later...
  • 1 month later...

I have the same error at boot; no sound for me, but sad Mac error shows immediately with 00000005  and address of 00080000.  If I pull the memory board out, I can get past this error and boot from the built-in system rom, but System 7 on the hard drive doesn't have enough memory to boot.  I've examined the motherboard for any damage and so far cannot find anything... it looks pristine.   I cleaned it anyway in case of capacitor leakage, but no difference in behavior.  So far I can't find a clue to the cause, but I'll post a follow-up here if I figure it out.

Edited by SkyBry
Spelling error.
Link to post
Share on other sites
  • 68kMLA Supporter

I would start buzzing out all the memory lines per the schematic. If there is good continuity, there are a few chips related to memory that are generic and are cheap enough it’s worthwhile to just replace them. Of course that’s assuming the memory cards are good.  I fixed my Classic that was only showing 512k ram that way (search here for Classic 512k ram or something similar)

Link to post
Share on other sites
  • 68kMLA Supporter
On 11/30/2020 at 9:45 PM, superjer2000 said:

I would start buzzing out all the memory lines per the schematic. If there is good continuity, there are a few chips related to memory that are generic and are cheap enough it’s worthwhile to just replace them. Of course that’s assuming the memory cards are good.  I fixed my Classic that was only showing 512k ram that way (search here for Classic 512k ram or something similar)

Just emphasizing this — I don't have a lot of experience with replacing ram chips, but if I learned anything from watching Adrian's Digital Basement, it's that ram chips fail very often (even new chips!)

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...