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| Macintosh Classic Sad Mac RAM expansion error |
Posted by: wintr on 2020-08-31 01:12:54
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.
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Posted by: plb007 on 2020-10-17 20:59:43
Hi,
I've got a similar problem, but without the second line (00000000)
Did you fix your problem, and (if yes) how ?
My recapped classic boots fine without the ram expansion in, but boot with this memory error when inside.
Regards,
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Posted by: SkyBry on 2020-11-30 17:49:24
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.
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Posted by: superjer2000 on 2020-11-30 21:45:13
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)
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Posted by: dochilli on 2020-12-01 03:01:05
Just an idea:
00000001 A0? ; 00000002 A1?; 00000004 A2? 00000008 A3?
00000010 A4? ; and so on?
00100000 would be A20?
00080000 would be A19?
Do not know, if I am right, but could be possible.
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Posted by: Stephen on 2020-12-02 20:04:32
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!)
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Posted by: techknight on 2023-08-22 05:50:41
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.
Necropost....
I just ran into a Classic doing the exact same thing.
I am suspecting the 74LS174, I will know further when i get back to it. |
Posted by: PotoMac on 2024-04-01 09:29:07
Me too...
Did you happen to find a solution to this?
My Classic with an AMP 2-532955-4 RAM card gives me a 00000005 / 00010001 error when booting but is fine with a regular Apple RAM card or none.
The Classic is recapped on both boards and has no other issues AFAICT. |
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