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Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: k4lmp on August 13, 2012, 01:20:39 AM
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I just purchased a MegaChip for my A2000. It looks like you pull the Agnus chip, and plug this in. It has the 8735, and is supposed to up my A2000 to 2m chip ram. I am just concerned about pulling the PLCC chip and replacing it with this. I will buy a PLCC chip puller, but after all these years, who knows if the socket will be OK, or break apart. Also, there is a jumper you have to attach to a pin on the processor, or on another chip, of which I can't remember. How hard is it to get the jumper on the pin and situated so that it won't short against the adjacent pins? I assume this is for clocking or such. Anyone else have one of these? Thanks.
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With a PLCC puller, the Agnus chip will pop right out. The Megachip will insert easily. Press firmly and make shure it is properly seated and you will be good to go. I did this years ago. As I remember there are two places you can clip the jumper to, one on the 68000 and one on another chip the 68000 lead is connected to. The clip is designed to prevent shorting but a lot of users cut off the clip and solder the wire to the pin. If your soldering skills aren't up to it, don't try it, just use the clip.
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BEFORE installing the MegaChip, wrap a nylon wire tie around the Agnus socket and tighten it snug. Do not over tighten. This will help keep the Agnus socket from splitting over time. Do NOT use the clip. Find a "thru-hole" that connects to pin 36 on the Gary chip or pin 48 on the 68000 chip and solder the wire from the MegAChip to this hole. It would be best if you remove the Amiga 2000 motherboard, so that you can solder the wire on the solder-side of the thru-hole.
If you do not actually NEED the extra meg of Chip ram, do not bother installing a MegAChip. It does put a lot of stress on the old Agnus socket, and if the socket splits, it is a major repair. So, do not let your ego cause you to damage an otherwise perfect Amiga 2000 motherboard. In most cases, one meg of chip memory is plenty.
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if you have a PLCC puller it comes right out no problem. I've done this countless times on a2000s of various ages and conditions and only once cracked the socket. You will be fine the tool is designed for it, it even holds the chip when you pull it out and its very easy even for someone not comfortable with this kind of upgrade/repair. So go for it!
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BEFORE installing the MegaChip, wrap a nylon wire tie around the Agnus socket and tighten it snug. Do not over tighten. This will help keep the Agnus socket from splitting over time. Do NOT use the clip. Find a "thru-hole" that connects to pin 36 on the Gary chip or pin 48 on the 68000 chip and solder the wire from the MegAChip to this hole. It would be best if you remove the Amiga 2000 motherboard, so that you can solder the wire on the solder-side of the thru-hole.
If you do not actually NEED the extra meg of Chip ram, do not bother installing a MegAChip. It does put a lot of stress on the old Agnus socket, and if the socket splits, it is a major repair. So, do not let your ego cause you to damage an otherwise perfect Amiga 2000 motherboard. In most cases, one meg of chip memory is plenty.
Well, I completely understand the theory of not installing it. However, I bought the A2000 to play around with and learn about Amigas. I was not fortunate enough to have been able to afford one when they were new, only the C64/128 stuff. It wouldn't be in the spirit of why I bought it, to be afraid to upgrade it. I don't use it for games and such, just to tinker on and play around with. I do run AmigaOS 3.9 on it, sometimes, though, so I imagine it would help speed things up a bit.
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BEFORE installing the MegaChip, wrap a nylon wire tie around the Agnus socket and tighten it snug. Do not over tighten. This will help keep the Agnus socket from splitting over time. Do NOT use the clip. Find a "thru-hole" that connects to pin 36 on the Gary chip or pin 48 on the 68000 chip and solder the wire from the MegAChip to this hole. It would be best if you remove the Amiga 2000 motherboard, so that you can solder the wire on the solder-side of the thru-hole.
If you do not actually NEED the extra meg of Chip ram, do not bother installing a MegAChip. It does put a lot of stress on the old Agnus socket, and if the socket splits, it is a major repair. So, do not let your ego cause you to damage an otherwise perfect Amiga 2000 motherboard. In most cases, one meg of chip memory is plenty.
That's really overkill. The clip works fine. The problem would be if the A2000 got moved around a lot. In that case, it would be best to solder the lead to the pin on the 68000. No need to take the MB out. This is the sort of work that was done at the factory a lot to put in last minute engineering changes.
2mb chip ram is a vast improvement and worth installing. Back in the day, the A2000s 1mb chip ram got to be more and more a limitation as software started to be written for 2mb chip ram A3000s and A4000s.
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Yeah, I've had my Megachip for a bit and no problem using the clip...
Also, I had an Insider II in my A1000 for a long time and it had a similar clip.
It even survived shipping to me...
Those clips are pretty good..
Now, soldering is always a better connection, but those clippy things are pretty reliable..
desiv
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Now, soldering is always a better connection, but those clippy things are pretty reliable..
Back in the day I found that using the clips allowed oxidisation which made it very unstable. I soldered the wires to a row of pin headers that then sat between gary and the motherboard.
IIRC on mine it was 4 wires as there was 2mb on the megachip board which was used for all the chip ram, the motherboard chip ram was unused and the 512k ranger memory (if configured) was still there. I need to test it still works as I'm likely to sell it soon.