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[cabbit]

Greetings,

I am in need of some assistance in diagnosing an issue with my Amiga 1200 and Blizzard 1230 MKIV setup. I seems that the amiga will only fully boot when the ram is removed, or when i click disable cpu caches at start up.

When both are inserted i get amiga dos with a cmd prompt (Failed returncode 20) and no workbench, if i try "loadwb" it tires to load however the screen will be covered with artefacts. Booting a wb 3.0 disk will only display artefacts unless i have the ram removed or cpu caches disabled.

I have tried all my components individually on my friends amiga 1200 and they all booted up to wb 3.0 successfully without issue leading me to believe something is up with the motherboard, however my motherboard is in very neat condition so i would like to avoid replacing it.

Appreciate any ideas and suggestions on how to get this all running.

[paul1981]

Originally Posted by cabbit

Greetings,

I am in need of some assistance in diagnosing an issue with my Amiga 1200 and Blizzard 1230 MKIV setup. I seems that the amiga will only fully boot when the ram is removed, or when i click disable cpu caches at start up.

When both are inserted i get amiga dos with a cmd prompt (Failed returncode 20) and no workbench, if i try "loadwb" it tires to load however the screen will be covered with artefacts. Booting a wb 3.0 disk will only display artefacts unless i have the ram removed or cpu caches disabled.

I have tried all my components individually on my friends amiga 1200 and they all booted up to wb 3.0 successfully without issue leading me to believe something is up with the motherboard, however my motherboard is in very neat condition so i would like to avoid replacing it.

Appreciate any ideas and suggestions on how to get this all running.

Have you tried a different power supply?

[cabbit]

I unfortunately don't have another to test with, my mates psu was non functional. However with his motherboard and my internals i was booting up into workbench without a hint of failure. My guess is perhaps this timings issue i've read about.

[billyfish]

Hi

There are 2 jumpers on the 1230; one for mapping the rom to ram and the other which sets the speed to access the ram. Try setting the speed jumper to 70ns as I remember having problems when I used a simm labelled as 60ns on the fast setting even though it should have worked.

[cabbit]

Hi billyfish i have tried on 60/70 and maprom/no maprom each has about the same result i am afraid.

[paul1981]

Originally Posted by cabbit

I unfortunately don't have another to test with, my mates psu was non functional. However with his motherboard and my internals i was booting up into workbench without a hint of failure. My guess is perhaps this timings issue i've read about.

Depends on what revision your A1200 motherboard is. What do you have in there?

So this is a new build then? I was under the impression that your system was working correctly and then all of a sudden it stopped working correctly.