aca500plus boots to green screen exc36 'E0'

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  • Jens, here's a business opportunity for your company. You'd make a killing if you made OEM quality PSUs. After reading up on the mean well PSUs I don't think it will have damaged a stock Amiga 500 with your aca500+ attached. He only used it 4 times in 6 months. I've got one in my 1200 with Amitek Hawk with 40mhz fpu and 8mb ram and it is rock solid.

  • Unfortunately making a PSU is prohibitedly expensive for a small company, because of the cost of the certifications that are required to make such a PSU. Thats why there are a lot of "PSU" on the market that consist of a ready made module from some big manufacturer.

  • That said, the plan has always been to make a DC-DC converter, so a modern switchmode PSU with high efficiency can be used. Just like the Commodore power supplies that we have in the shop now, we can have these made by a larger company and get all the required certifications and paperwork for our product liability insurance. On the low-voltage DC side, there is only CE/FCC to observe, and that's daily business for us.

    The acceptance of such a unit would still be limited, as you'd have a two-box-setup: A laptop-like AC-DC power supply and another box that contains the DC-DC converter. Further, there's another weak part inside the Amiga, and that's the current-compensated coil at the power-entry point. Here's where another voltage drop happens, so yet another connector would have to be introduced, likely reducing the acceptance of the solution even more.

    Then there's the problem of getting the 5-pin square DIN male connectors. None of the connectors that I have found are RoHS-compliant, because they are "new old stock" from the 1990s. Since the sources that I have talked to a few years ago are depleted now, my guess is that these non-RoHS parts have now changed hands to those who are offering those "new" power supplies. If we wanted to get that fully legal, we'd have to make new toolings to have new, RoHS-compliant 5-pin square DIN connectors.

    However, I'd still be hesitating to spend that kind of money on tooling, because the 5-pin female square DIN connector on the computer side is rated for 2A of current only. Commodore gave it a stretch from the very beginning with it's 2.5A rated PSUs for the first A500 computers and the C128 (which is also 2.5A rated on the 5V rail), and then continued to stretch it up to 4.5A, bearing the danger of the connector burning with a high-powered setup that loads the 5V rail excessively (for example with a B1260 or Apollo 1240, which is even worse).

    So if you look at this from an engineering point of view, there is only one way to get things absolutely right, and that's to make a circuit board that replaces the 5-pin DIN connector AND the current-compensated coil that's located right behind it on the A500/A600/A1200 boards. This would probably have yet lower customer acceptance, as it would be an expert-only-install.

    However, it would eliminate the weak point of the connector, the voltage drop on the input coil would not have to be accounted for, and the outer appearance would be even nicer, as a new laptop-like PSU is much smaller than the old bricks. The DC-side cable would be thinner because it only has one core plus GND/Shield, and I bet the overall efficiency would be higher than with the old bricks, so you'd even save money on your electricity bill.

  • Got a selfmade ATX 350W PSU and use it every day since 2016 with the AMIGA500 Rev6A/Indivision ECS V1/ACE2/ACA500Plus 2016/ACA1221EC/RTC/X-SURF 500. Never got trouble with it and use it also on my AMIGA 600/1200.

    For the C64 Reloaded MK2 it’s great to use the PSU from Individual Computers.

  • ATX 350W PSU

    Please be careful with ATX: These have mostly the 12V rail as their main regulation rail, which puts the 5V rail in kind-of-a random regulation status if the 12V rail is nearly-unloaded like it's the case with Amiga computers. You may be lucky with the specific type you have there, but the general rule of thumb is that the delivered power on 5V must be higher than on the 12V rail, and that's not the case for most of today's ATX PSUs.

  • i would have thought 350w is to powerful and will burn itself out running an Amiga.

    Jens, regarding the ACA500+, my mates gonna leave it and stick to the old fashioned floppies. There's no way of telling what causeditt to fail. And you said its beyond economic repair and cheaper to purchase a new one. So he's decided to keep it completely retro.

  • Ah ok :-/ although I saw that they said in the link they had updated the tooling to make more !


    We found a stash of them and then talked the manufacturer into reworking their tooling to make new connectors! We are happy to offer these to the Commodore enthusiast, so they can repair their power supplies and/or build new ones to keep these fantastic vintage computers alive.

    We want to make these available to everyone and recognize they are in very a limited supply, i.e. we will make them available as long as the manufacturer will make new ones. Please order what you need but don’t horde them. It would be nice for everyone who needs them to get them.

  • Doesn't look like it, no - if you really make a new tooling, then you make thousands, not hundreds, and that means "no short supply" for the Amiga world. You don't put tooling on a machine for just a few hundred connectors, because just getting the tooling on the machine is something like 1-1.5 hours. Then you run the machine for an hour and have over 1000 connectors, given a cycle time of around 3 seconds. That's the reason why most of the China manufacturers have minimum order quantities of 3000 to 5000 units.

    So yes, this is new-old-stock, not RoHS compliant and with the same weakness that all these connectors have: They are rated for less current than most Amiga computers take.

  • Jens, rather than send the card back, id like to see if i can fix it (because im in the uk). Everything looks good but the dismo board looks wonky, is there anything I can try before i throw it in the bin?

  • You most likely don't have the equipment to check components. There's no customs border between UK and Germany (at least not yet), so I'd say you ship it here - it's not that expensive, and we can figure out what's wrong pretty quickly.

    FWIW: Why do you believe that it's just the DisMo that's not working?

  • sorry Jens i didnt get a reply in my email, i threw the board away today. Im here because ive bought an old heavy psu and id like to buy a recap kit, can you point me in the right direction?


  • Please understand that we can't recommend other vendor's products here for liability reasons. I'd suggest to go with a service that sells both the caps and the installation service.