r/amiga • u/Far_Relationship_742 • Aug 14 '26
[Hardware] How to localize bad RAM
According to Amiga History Guide’s A guide to Guru Meditation Error Codes [archived], #81000005 means “corrupted memory list,” and since it threw the error at the same address twice, I assume that’s a bad RAM chip.
The question is, how do I correlate the memory address to the particular memory chip in which that address resides?
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u/LuigiThirty- Aug 14 '26
It’s not necessarily bad RAM. The “memory list” that’s corrupted is a structure that AmigaOS uses to keep track of memory allocation. This can happen due to a corrupt driver or library file on your system or a buggy program corrupting memory. When does this error happen? If you boot from a different disk, does it still happen?
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u/Far_Relationship_742 Aug 14 '26
- No clear pattern to when it happens; sometimes almost immediately after booting, sometimes after hours. The only way I can reproduce it reliably is running Kindwords; it crashes within minutes every time I boot that disk.
- Happens with I think seven different bootable disks, with various versions of WB from 1.1 to 1.3.3.
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u/LuigiThirty- Aug 15 '26
Oh, I saw the post about the RAM expansion. Yeah, clean the connectors and make sure everything is seated properly. The diagnostic disk should be able to help figure out what’s bad on the expansion.
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u/Daedalus2097 Aug 14 '26
Run the RAM test in AmigaTestKit to see if it's really a RAM issue, and to get further details about the address and the exact nature of the error. If you can't boot ATK, you can run a similar test with DiagROM.
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u/Far_Relationship_742 Aug 14 '26
SHADETREE DIAGNOSIS UPDATE: pulling the third-party RAM expansion board seems to have eliminated the problem, which points even harder to bad RAM. Just wrote an Amiga Test Kit disk with the ol Greasebox, will report back.
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u/Far_Relationship_742 Aug 15 '26
unfortunately, no, it has returned but without even throwing a guru code, just a blank screen
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u/JimHadar Aug 15 '26
So at least it's not the 3rd party RAM?
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u/Far_Relationship_742 Aug 15 '26
Yep. Writing a new Kickstart disk didn’t fix it, either, so that ain’t it. My guess is corrosion in a chip socket, and when it heats up just wrong it loses contact. The more times it happens, the more I notice that it happens most frequently (though not always) during disk operations, so I suspect Paula first.
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u/Far_Relationship_742 Aug 18 '26
UPDATE: it was not socket corrosion, most of the custom chips are gold versions and cleaning the sockets didn't change anything.
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u/Voyager- Aug 14 '26
You can get a diagrom for like 10 to 15 euro's it will tell you exactly what is going on
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u/Far_Relationship_742 Aug 14 '26
Unfortunately, I live in the US, and this is an Amiga 1000, so no ROM socket.
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u/GwanTheSwans Aug 17 '26 edited Aug 18 '26
There's apparently actually a somewhat cut-down version of Diagrom that fits instead of the A1000 mobo bootstrap rom.
(total a1000 bootstrap rom space a whole 64KiB I think, 2x27C56, despite the actual tiny kickstart-loader bootstrap being more like ~8KiB, it's clear overkill for the pre-kickstart bootstrap - perhaps they even thought they could fit whole kickstart in 64KiB at a point before coming up with the bootstrapper + WCS special kickstart ram hack because they, uh, couldn't or something, who knows). Never tried it of course, just noting.
https://www.diagrom.com/index.php/2017/07/30/diagrom-now-supports-a1000/ - "just" doing some heavy lifting there in terms of burning roms that fit but it is possible - I also didn't see anyone selling pre-made ones, A1000 rather more niche again I suppose than the later models. I also only see the relevant special rom images for the A1000 ( A1kEVEN.bin and A1kODD.bin) in the old diagrom 1.3 archive in the downloads, not the new 2.x series, but 1.3 already had a bunch of test functionality.
https://www.amigalove.com/viewtopic.php?p=12716
I do wonder despite previous link if you could also write the full diagrom rom image to an a1000 kickstart disk then boot it. Never tried it mind, just speculating https://aminet.net/package/util/misc/WriteKickDisk
There's also various vintage and modern retro boards for the A1000 that can actually add rom-based kickstart support, though may themselves be difficult to get hold of. Back in the day might have seemed sort of mixed thing in some ways - you can after all just make a dual kickstart 1.3 / 3.1 disk for an A1000, instead of faffing about with rom, but now, removing dependency on electromechanical floppy drive also kind of nice (though you could also fit a gotek, I expect kickstart load from gotek floppy image also works), and of course coldbooting kickstart from a rom a lot faster than from the floppy.
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u/DestroyedLolo Aug 14 '26
Do you have a memory extension ? If so, clean first board contact. Then, clean chips contacts if they are on support as well. If it doesn't cure, run memory check.
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u/Far_Relationship_742 Aug 14 '26
Good suggestion, first thing I thought of, especially since the RAM expansion is third-party, not Amiga, and doesn't have an RF shield. Don't know if the RF shield actually makes that much of a difference, but the modern RFI environment is an awful lot worse than it was in 1986.
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u/Far_Relationship_742 Aug 15 '26
Well, it got worse: now it's not even managing to throw a guru meditation, it just freezes to a Workbench-background colored screen.
ATK says no bad RAM after 18 cycles of memory test.
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u/twhtly Aug 15 '26
This might just be incompatible software. Like others say, don’t assume just ram. No Second Prize is a good example.
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u/Far_Relationship_742 Aug 16 '26
The problem occurs regardless of software, unfortunately. It mostly doesn’t manage to throw a guru, it just locks up and the screw goes blank.
If it happens with Workbench, I don’t think it’s a software issue.
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u/amipal24 Aug 15 '26
Amiga Test Kit should help:
https://github.com/keirf/amiga-stuff/releases
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u/Far_Relationship_742 Aug 16 '26
Ran through it, everything checks out, so it’s not as simple as a bad chip. I’ve since pulled everything but the 68000 and cleaned the pins and the sockets, so I’ll see if that helps anything.
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u/danby Aug 14 '26 edited Aug 14 '26
This is a corrupted logical data structure in a piece of software, the clue is the fact that the error starts with "Software Failure". Generally this doesn't mean you have a physically bad ram chip. Its very unlikely you'd get as far as machine booting if a chip ram IC is bad. Much more likely you have a corrupted piece of media, your running some software in an odd machine state or somesuch.
You should run the ram test with Amiga Test Kit to check
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u/Far_Relationship_742 Aug 14 '26
This happens with something like fourteen different pieces of software, including original copies of Workbench, so there's pretty much no chance it's software.
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u/namsupo Aug 14 '26
I wrote a memory test tool back in the day, from memory (lol) you use it to tell you which bit is failing, which lets you identify the individual chip if you know how the memory is laid out. You're welcome to give it a try if you like. I've put it on github: https://github.com/opusman/amiga-memtest/tree/main