ACA500plus + ACA1234 CPU switching crash

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Don't Panic. Please wash hands.

    Hi all,


    I recently purchased an ACA500plus and an ACA1234 to use with my Amiga 500. I'm really impressed with the combo, and my young self back in the day would have been completely astonished at what the humble A500 can do these days!


    However, I have encountered one minor problem. I've done the requisite firmware upgrades, so the ACA500plus menu is now giving me the option to switch to 68000 mode. When I try to switch (F3 then X), the Amiga reboots back into the menu and then a few seconds later it locks up. The starfield stops and the menu doesn't respond to keypresses. Doing a CTRL-A-A at this point results in a black screen, and at this point there is no status number on the ACA500plus. The only option to recover is a power cycle.


    It's a vanilla rev 6a board, with the 512k trapdoor expansion installed. Here's the firmware versions on the ACA cards:


    ACA500plus menu V0.146

    ACA500plus installer 1.5

    ACA1234 firmware 20230124


    This problem isn't the end of the world but on the odd occasion when I want to play a game, I may need to fallback to the 68000 and I'd rather avoid having to physically remove the ACA1234.


    Other than that, everything else is working like a charm and I'm a very happy customer! :)


    Cheers,


    S

    Please check the maximum frequency setting that you've chosen for the 68ec000: This won't be overwritten when you make the software update, so it may still sit at something higher than 14MHz. Make sure it's set to 14MHz, save settings and try again.


    Further, the ACA1234 will continue to draw some power, even with the CPU switched off. Your power supply may output ripple on the 5V rail, and the 68ec000 CPU is actually way more susceptible to power inconsistencies than the 68030 CPU is. What type of PSU is it, and is this 110V or 230V grid?

    Please try a different PSU, if available. It's the best guess I currently have. The other possibility would be to re-cap this PSU, as it's quite old by now.

    Pleas emake sure that it's suitable for an expanded Amiga. Most commercially-offered units are just offered with false advertising, claiming 4A on the 5V rail (like the Polish type offered on Amazon and the one from Amigastore): They are proper chassis, but they are not made to work with a distant power sink. So just adding a cable and connector does NOT make an Amiga power supply.


    Read all about the tech details in our PSU FAQ.

    Hi Jens,


    I've managed to test with another PSU and Amiga 500, and the same problem also occurred with these. The PSU specs: +5V 4.3A, +12 1.0 A, -12 0.1A. Not sure what rev the A500 mainboard was.

    Please try launching with 68000 CPU, then go to the global menu: Is the speed limit set to anything higher than 14MHz? If so, please set it to 14MHz and re-try launching the unit with the ACA1234 connected.

    I launched with just the ACA500plus and confirmed that the 68000 speed limit is set to 14MHz. Then launched with the ACA1234 connected and tested CPU switching again, with the same result unfortunately.

    What's the ACA1234 speed? You may observe a difference when running at a different speed. Also, I'd like to look up the database entries for your cards - please mention the warranty IDs of your ACA500plus and ACA1234.

    Based on your comment about the ACA1234 speed, I thought I'd try dropping the speed to 40MHz and that worked perfectly. Anything 40MHz or lower on the ACA1234 works reliably with CPU switching. Putting it back to 50MHz recreates the issue.


    I can live with that! Thanks for the advice Jens. If you still want the warranty IDs for further research please let me know.


    Cheers,


    Steve

  • The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.

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