ACA1240/60 Fitting to A1200 Under or Over the 'Rail'?

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    Hi,


    I've done what I hope is the 'final' fitting of my ACA1240 now (i.e. I don't intend on removing it from the machine, or changing chips any more or anything) - but I have a question.


    If you look at the picture, the "top, back" part of the card - is it meant to sit under, or 'over' the white plastic rail of the case?


    At the moment it's sitting "over" this (not amazingly clear from the picture). If I sit it 'under' that overhang two things happen - if you're not careful it puts pressure on that ESMT chip (i.e. shown as the red circle in the image) - and, the card is 'too low' (even with the extra feet on the Amiga) that the fan seems to catch on my desk (i.e. the card 'droops' down, and you can hear the fan catching).


    I can see there's a black foot on the fan on the card - so I'm not sure how it's managing to catch on the desk (as it's obviously hard to see), but thought I'd check the obvious first (i.e. should it be fitted 'over' or 'under' that white 'rail'?)



    Thanks!

    The picture shows the intended position: The circuit board pushes against that white rail, and the ESMT chip (that's a RAM chip) barely clears it.


    Jens

    Humm... I honestly put the card "under" the white plastic holder.


    Doing over, so I hope correct, seems to solve the issue with th fan getting out too low (addind more "feet") like in the thread of the German forum.


    So maybe the other user there did put the card "under" causing the feet size issue.


    For sure, some photos of the correct way to fit it on the wiki would help.


    Cheers.

    Nico

    Ok,


    Better picture (you really can't see on the first).


    This shows how the card is installed ("over" the rail). If I try to install it under the rail - the white plastic lip of the rail (which is quite sharp) puts pressure on that ESMT ram chip as it's at exactly the same height. Maybe this could be fixed by unscrewing and 'shifting' the mainboard a bit if there's any play in it - but that's how the machine is at the moment.


    With the card fitted 'above' the rail - it's at a slight upward angle, but the fan no longer sounds like it catches on the desk - and the card doesn't "droop" when you pick the machine up. Also, carefully looking under the machine - the black rubber foot on the fan - is touching the desk.


    I still have the extra feet fitted to the front of the machine.


    Hopefully that's better shown in this picture which is the same as the original picture - but at a better angle to show how it's installed.


    Thanks.


    It makes also more sense for the upcoming GFX card. It fits better like this for me and solve some issue a guy has on the German forum.


    Cheers

    While it's actually not intended like that, I just tried it: It does feel a bit tilted (so filing down that sharp edge might help), but the soft edge of that part touching the other six memory chips might be a solution for setups where it doesn't fit otherwise.


    The GFX card is intended to be a bit smaller, so it'll definitely pass the edge that's reaching in.


    Jens

    I purchased an ACA1240 last month and I have fitted it to my Escom A1200. I did some experimenting with a modified trapdoor cover for this card that gives it some support. I also printed some feet (non-rubber, blue in photos) for all four corners of the case underneath that lift the case up by 8mm, and other versions (white in photos) that lift it up by say 4mm and then you add 4mm rubber feet (from am*zon) to make it up to 8mm (or less).

    The trapdoor cover has been stiffened along it's length. I want to do some more stiffening one of the long sides (top in photo) to stop it potentially warping over time.

    I have attached some pictures of the design so far and just wanted feedback and advice as to whether this is a good idea or not, is it worth doing, and any other ideas you have? Has someone already done this, does it frustrate the cooling, does it cause problems where it touches the card in one corner (top left-hand corner in photo) etc?

    N.B. In the photos: If I removed the black rubber foot on the fan then the card would not descend any further as the modified trapdoor will stop this. This means I could reduce the height of the 3D-printed feet I have made, but to be honest extra airflow under the case is probably needed? If you need more clarity (if it's not clear in the current photos) on how the card is being supported then I will upload another photo when I get some time this weekend.




    It is very clear how the card is supported: You've added a stand-off "foot" to the inside of the cover (or should I say "window"?). The small black rubber foot makes sure that the fan gets enough "source air". The general direction of air should be "right to left" under the computer. The amount of air needed is very small, which is why the fan hardly ever spins any faster than minimum speed. As long as the rotor doesn't touch the table, everything should be OK.


    Jens

    Thanks for the feedback Jens.


    I will report back when I finalise this (which will be this January) and how I intend to socialise/distribute this window/picture frame.

    Quote from kryton

    Thanks for the feedback Jens.


    I will report back when I finalise this (which will be this January) and how I intend to socialise/distribute this window/picture frame.

    Hi kryton, how have you found using your modified trapdoor? Did you have any issues?


    Would you be able to share the stl file for your modification?


    Thanks :)

    Hello origin,


    As I do not have access to a 3D printer, my friend has been helping me out, but he wasn't holding the STL file in version control and regressed some changes we made..so I lost some time. To cut a long story short the feedback loop is about 4-6 weeks between iterating the design and getting the trapdoor in my hand etc. It's quite tiring :)

    I have thrown together some documentation today/this evening on github about where I am at the moment, including all the required files for 3D printing:


    https://github.com/not-kryten/amiga-hardware-projects/tree/main/aca_1240_1260


    I do want to make some more adjustments, but it is functionally useful for me at the moment. I tried to stiffen the edges as much as possible - see the README.MD file for details. Also, I'm not great at this sort of stuff :)

    Print it out and give some feedback.