ACA500PLUS instability issues

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Don't Panic. Please wash hands.

    Dear Individual Computers/Jens


    I have an ACA500plus (2013-2016), warranty code: nTJAy, that I purchased from you in February this year. This is a replacement for the first one that I recieved, which was dead on arrival.


    For a few months I have experienced instability issues (games freeze, Guru Meditations, green screen...) with my setup: Amiga 500 (v. 6A), ACE2b and the aforementioned ACA500plus. The problems have increased and now I cannot boot Workbench from the CF-card used as Boot device in the ACA500plus.


    Usually, when the system has booted to the ACA500plus start screen, a LED on the ACA500plus shines alternating between blue and red. The display shows "FE". I have no idea what that means but I assume it is not a good thing. Sometimes, instead of the Start screen, the screen goes green with cryptic numbers shown on it. At that moment the ACA500plus display shows "E0".


    I have tried to reinstall Workbench 3.1, using the install tool included in the ACA500plus. Sometimes it freezes during installation, sometimes it freezes after the reboot.


    I have been using the Commodore original PSU. I have borrowed a 3'rd party vendor PSU from a friend to test, but with no different outcome. Should I try your own Amiga 500 PSU that you are selling?


    In every configuration with the ACA500plus disconnected, the Amiga works fine. None of the aforementioned problems occur. Using the ACE2b or not, doesn't make any difference. So I don't suspect that to be an issue. I have also tested the motherboard using Amiga Test Kit v1.18 and DiagROM 1.3 flash rom kickstart. Neither tool shows anything wrong.


    I have even purchased another 6A motherboard (recapped and tested to be working), complemented with tested and working chips (all of them). This is practically a whole different Amiga, excluding the chassis. The problem persists, so I don't suspect any issues with the Amiga. I have tested the ACA500plus with this other motherboard in the same different configurations as with my original motherboard. I have also run the aforementioned diagnostic tests. The behavour is similar.


    Now I don't know what else to do apart from asking for your help. What should I do to solve this?

    Quote from PeterPan

    Usually, when the system has booted to the ACA500plus start screen, a LED on the ACA500plus shines alternating between blue and red. The display shows "FE". I have no idea what that means but I assume it is not a good thing.

    You're assuming wrong. The FE is just showing the first scan code that the keyboard is sending, and that's the "no key pressed after power up"-confirmation that the Amiga keyboard is sending. So nothing to see here - at least nothing negative.


    Quote from PeterPan

    Sometimes, instead of the Start screen, the screen goes green with cryptic numbers shown on it. At that moment the ACA500plus display shows "E0".

    That's an exception. Since you're using an ACE2b, there might be a contact problem between the chip ram expansion and the main board. Please give the socket a good cleaning with an old toothbrush and IPA. Don't use contact sprays, as they usually contain additional lubricants that don't belong in a computer socket.


    Next thing to check is the max. overcloking setting in the global settings of the card. Note that even if you're launching a 14MHz profile, the menu system will crank up the speed to max when starting, in order to keep wait times low. That's when you see the black text on white lines of background flashing by after selecting a launch profile. If you have set a too-high overclocking speed in the global settings, the system will crash at this spot. Since you have the version with 68ec000 CPU, the recommended setting is 14MHz here.

    Now I have had the opportunity to play around with my aca500plus and a500. Here are the results from me trying your suggestions.


    I thoroughly brushed the contact surfaces of the aca500plus and the expansion port on the left side of the a500, with alcohol and a new toothbrush. I also did the same thing with the Agnus socket and the ace2b. But initially after that, the same problem persisted.


    Suddenly I recalled watching a YouTube clip in the past, suggesting that it's wort trying to pull the aca500plus out just a tiny bit (like 1 mm.) of the expansion port. So I tried that and it all worked much better. No green screen and it boots up nicely with wb 3.1.


    Now I have another, possibly related, problem. I have erased and reinstalled the boot cf card with wb 3.1 using the built-in tool in the aca500plus. Straight after that I put the Kickstart 3.2.1 rom from Hyperion, in the KS slot and upgraded the boot cf card to wb 3.2. I have only used the original licensed install software from Hyperion. I have not installed anything else. Before booting I set the aca500plus to use the mainboard rom, using F10 - Expert options and then saving. But the bootup hangs with a guru meditation. Initially during bootup, there is briefly shown that Kickstart 3.1 r40.63 is used. If that is the cause of the problem, then how do I force the aca500plus to use the mainboard rom instead?


    It is the same problem if I connect the aca500plus to my other a500 motherboard with a different set of chips onboard. That has also been cleaned using alcohol and the aforementioned toothbrush.


    Both motherboards are Rev. 6A and the chips came with the boards. Agnus is 8372A but it's no difference if I use Agnus or my ace2b.


    Any further advice is most appreciated.


    Best Regards

    Peter

    Testing further, I need to add that I cannot load anything from my Gotek drive while the aca500plus is connected. I keep getting disk errors. If I disconnect it everything is loading just fine, without error messages. I'd appreciate any help on this as well.

    I forgot to mention that I have also checked that the speed is set to 14 Mhz. Both as the max setting in the global settings, and elsewhere (F10, F9 and F8 in the aca500plus menu).

    Looks like we need to go back to the power supply question(s), as you've already tried a lot of things that I usually ask. Given that you've had a "dead on arrival" card before (which is unlikely to be shipped that way, as we test each and every unit before it gets it's warranty ID), I have to assume that there is something fishy with your setup that harms the accelerator.


    I need to check the database for notes that were made about your first card - we usually repair everything, so we should have more information now that we've had back then. We'll only have a skeleton crew today for doing shipments, but I can put this on the agenda for January 2nd, 2023.

    CA-PSU is currently not available. With Chip-a-geddon coming to an end, I'm hoping that we can deliver some time in the first half of 2023.


    I just looked up your case - iRep1084 was an actual repair, not an exchange, so you got the exact same card back. The defect was a mechanical one: The button on Dismo was pushed so hard that the silicone that holds it was deformed enough for a pin of the button to pierce a trace on the other side. I can see that the trace was repaired, the pin on DisMo was shortened and DisMo mounted back with an extra quantity of silicone.


    I have my doubts that it's the same defect again, but it can of course never be excluded. After all, you were the first customer strong enough to push the DisMo button that hard :-)


    The 4.5A PSU from Commodore is a really good one, but it will require new capacitors after all these years. If you find someone locally to do that job and re-adjust the output voltage under full load (the "full load" part is important!), you'll have a high quality PSU for your retro setup.

    I really must emphasize that even if it was many months ago, I don't recall pressing the dismo button at all, never saw the need to do it. And even if I'd need to press it some time in the future, I know from many years of experience, enough about the delicate nature of electronic boards not to use more than gentle pressure. If not for any other reason, at least I don't want to cause any breaks in solder joints of the board. So if anybody pressed it too hard it wasn't me nor anyone else in my home. Or the button was broken to begin with - I can only speculate. I am sorry for needing to make this clear.


    My psu is the heavier but still weaker 2,5 Amp version from Commodore. Perhaps it is too weak to power both the Amiga and the aca500plus? I just discovered the CA-PSU in stock with your retailer GGS Data, at 100 euros. So I'm ordering that if you think my psu is too weak.

    I didn't mean to point fingers or even make you pay for the repair. We did the repair, didn't charge for it and also ate the shipping cost.


    The 2.5A PSU is indeed the low-end of the A500 power supplies, but shouldn't cause instability - unless it has never been maintained by exchanging the output capacitors. So yes, the 5V regulation may be off, or ripple might cause trouble after all these years.


    Thanks for the hint that GGS Data is scalping this way. That's 25% on top of the recommended retail price of 79,47 EUR. Even with the higher VAT rate in Sweden and some margin on top, it shouldn't be more than 91-92 EUR - does the price include shipping?


    We currently don't have it in stock, and if you're willing to spend the money, it's surely the best power supply you can get, as it will compensate for any cable loss on the source, keeping the voltage inside the Amiga at 5.0V with *very* little deviation.

    I have received the CA-PSU and tested it with my setup. Regretfully it's even worse now. I cannot boot to WB 3.1 and I cannot reinstall either. The Amiga just freezes in the beginning of either process.


    Do you have any other ideas or suggestions? Or should I return the board for you to have it checked out?

    I am still having problems with this unit. With both my motherboards and both your PSU as well as the original Commodore one. The display showing "E6" a few seconds after power up. How do we proceed from here?

    I don't have access to the database from here (still on vacation), but we don't ship out anything that doesn't work - especially when it was back for service, it's been tested especially to your fault description and won't be shipped back until we have reproduced the issue and removed the cause.


    Long story short: If the unit now runs into it's exception handler, you need to look for a problem within your A500s. I also have an A500 where I get such occasional exceptions with the ACA500plus: It has a bad Paula socket, and I need to re-seat the chip when that happens. Not that this is a common thing (hardly anyone will use the Indivision ECS A1000 adapter in an A500), but it shows me that the ACA500plus startup-phase is doing way more tests than Kickstart has ever made.


    Check your Agnus socket, check your Gary socket, these are the most common ones that fail.


    Jens

    I have never changed the max frequency. I'm just fine if I can make this work at all with stock settings.


    Since I have gone through the trouble and cost of buying another recapped and tested motherboard with all the chips, and your CA PSU, would it really be too much to ask for you to replace it with a different unit? Or my money back?