30 December 2021, 16:47 | #1 |
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A1200 Accelerator Cards: Thinner Edge Connectors
Hi All,
Does anyone know if there is a definitive list of cards for A1200's that don't have the thicker edges for connecting to the motherboard? I understand more recent cards have these thicker edges but I'm interested in ones that don't. Thanks for any help in advance. |
30 December 2021, 20:18 | #2 | |
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I have two A1200s, one is a 1D4, and one is a 1B, the 1B has a thicker, square edge, and the 1D4 is slimmer, and tapered off at the edge, is that what you mean? |
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30 December 2021, 21:00 | #3 | |
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Sorry I should have made things a bit clearer before! |
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30 December 2021, 21:13 | #4 | |
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Firstly, let me congratulate you, you win the internet today. I don't know any A1200 users who still have the RF shield in place, don't get me wrong, now there will be a deluge of, "i still have mine!". Sadly, i don't have an answer to your question, although now i am wondering how far over the RF shield, does it cover the expansion port? i will go look |
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30 December 2021, 21:19 | #5 | |
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The shield on mine has a lip which is raised a bit in fairness but comes right near (just over) where the edge connector on a card would be. Only fractional perhaps but if you have to slide the card in then the card will probably need to be slightly less high than the shield. My 8mb fast ram card fits fine, but I wonder about some of the newer cards as I mentioned before. |
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30 December 2021, 21:33 | #6 |
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Yeah, some motherboards for whatever reason don't have the edge connector bevelled, and this can cause serious difficulty installing accelerators, including mangling the contacts in the connector on the peripheral. But, indeed, that's not the issue being talked about here.
Any new devices I've seen have thicker than standard connectors. These new connectors have been newly manufactured, and it seems that whoever specced them, overlooked the thickness of the plastic body of the connector. Perhaps the spec was based on a modified PCI connector, since the contact design (pitch, card thickness etc.) are very similar. But if you compare these new boards (which likely all have connectors from the one newly-manufactured source) to old boards, they're clearly around 1mm or more thicker than cards from back in the '90s. This causes issues with installation, as there's not enough room *under* the motherboard for the connector body to fit between the edge connection and the bottom of the case. Slackening off the nearby motherboard screw a little is usually enough to sort that out, though it still means installation is a little bit more fiddly than it should be. The RF shield above the connector is another issue with some boards. It typically has a few mm of clearance above the peripheral board (and doesn't extend over the trapdoor area), but this depends on the top shield being correctly fitted. If it's bent, or incorrectly refitted after some work has been done for example, the edge can be lower than originally intended. This can mean it can touch the back of the card itself, causing shorts that could prevent booting and potentially damage things. This is compounded by the thicker connectors, which raise the back of the board by about 1mm, and loosening the screw to allow the connector to fit, which also loosens the shield. Typically this wouldn't prevent installation because the RF shield is easily bent out of the way by the installation force. |
30 December 2021, 22:11 | #7 | |
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what's your view on removing an RF shield altogether? is it worth considering? ta |
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30 December 2021, 22:49 | #8 | |
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I was thinking of trying to source an older card but I'm not sure though on dimensions of all the cards, hence the original query I had. Cheers for the feedback. |
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30 December 2021, 22:55 | #9 | |
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In addition to any standard instructions to remove the shield, there is another thing in that instead of a floppy drive I've got a Gotek housing (bracket) of some sort that has been fitted by the previous owner and it looks unclear if or how I'm supposed to remove it, but it looks like it goes over part of the shield so I'm guessing I may have to remove that as well. |
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31 December 2021, 00:40 | #10 |
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The upper shield prevents the Amiga from interfering with other devices nearby and was required for the system to meet emissions requirements when it was authorised for sale, but it's not needed for anything really. Most people have long since removed it, and many expansions require that it's removed. If you're unlucky enough to have a device nearby that's affected by the emissions from the Amiga, just move it another foot or two away and it'll be sorted.
The floppy drive and hard drive both need to be removed to take off the shield, but they're relatively simple to take out, and generally the upper shield doesn't have any mechanical support function. I don't know of any guide specific to removing the shield, but if you look for any guide for installing an internal scandoubler, Indivision, FastATA or similar, a part of that process will be to remove the shield. |
31 December 2021, 11:22 | #11 | |
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01 January 2022, 13:14 | #12 |
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I still have my RF shield in place. I'm not aware of any conflict with my Blizzard 1230 or my Vampire. The RF shield is an original part and some collectors prefer having them.
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22 January 2022, 16:53 | #13 |
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Hello, as for newer cards. I have ACA1233n and ACA1221lc. No problems fitting in original case with full shield, so not all "New" connectors have problems. I do hear that TF1230 and TF1260 and some memory only new cards need shaving of connector or loosing the screw if somebody can confirm please on Terrible fire cards at least ?
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22 January 2022, 18:48 | #14 | |
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You'd need to confirm with whoever you were considering buying from. |
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22 January 2022, 19:02 | #15 | |
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You are right. I am looking of getting https://amigastore.eu/ TF cards and if they can normally slot in to original cased Amiga 1200. BR, Luka |
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22 January 2022, 21:49 | #16 |
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Be aware the issue will be the A1200 board itself, very early revs dont have a chamfered edge connector and some connectors will not fit until you create a chamfered edge, its very easy to do...
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23 January 2022, 22:49 | #17 | |
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Thanks and BR, Luka |
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24 January 2022, 00:34 | #18 | |
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As much as I appreciate the effort that was put into these cards, yea I wish they came with a thinner connector.. the connector thickness can be a pain when installing the card. I tried to put one into a 1200.net case but could not get it to fit without modifying something or removing something. Yes I had to unscrew the motherboard too lift it up a bit but the plastic wedge that goes above the long side of the trapdoor sets an upper limit too, there really isn't a lot of room there, height wise. FYI the thickness of the connector on my card is 8.1 or 8.2 mm. Not sure how the 1200.net cases compare to the original case in this particular detail though. I should probably do some precise measurements some day ;-) |
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28 January 2022, 13:14 | #19 | |
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However, if you look at these reproduction connectors, they appear to have used the standard PCI connector as a basis for the design (and that goes for the IComp connectors as well). Probably a sensible option, given that they share a common pitch and board thickness, and that the contacts and insertion equipment will already exist and require minimal modifications. But it could simply be that whoever specced them simply didn't consider the thickness - any new cards I've measured, both IComp and other 3rd party, have connectors around 8.7mm thick (which is the same as standard PCI connectors), whereas the connectors on any old accelerators from back in the day are around 7.4mm thick. It's a significant difference, and inserting a either an ACA1221 or a TF1260 into my A1200 lifts the motherboard by around 0.5mm - something that doesn't happen with a Blizzard 1230, for example. Of course, being Commodore, it's possible that there are cases out there with a little more room and are enough to accommodate the newer connectors. As well as that, I find that many machines these days are missing some screws, and you can find some motherboards aren't screwed down, thus allowing the newer connectors to fit just fine. Incidentally, having no motherboard screws also allows the top shielding to naturally sag and come closer to the accelerator connector. It's not really a hard and fast rule - I've seen a few different revisions with non-chamfered edges, so more likely to be individual batches that slipped through QC here and there. But without seeing the machine in question, it's impossible to tell for sure where the issue lies. I've seen far more A1200s that are excessively tight with the new, thicker connectors than I have with unchamfered edges so that's where I'd put my money, but the chamfer is always worth checking for. |
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05 January 2023, 00:19 | #20 | |
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what's the best approach to chamfer the connector without making a complete balls of it ? thanks |
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