A4000 memory upgrade /newbie problem/

[b00mer]

Hi, I have recently bought used A4000/30 (previously been A1200 user). It came with only 2 Mb chip RAM and no harddrive, but with a network card. Strange setup, I know.

Anyway, I would like to upgrade the RAM first to maximum (16 Mb fast). I have bought 4 SIMMs of 8 megs (got 2 for free . I have a problem inserting them into spare sockets. It seems like they don't fit. I am affraid of damaging my Amiga, so I don't want to use force or something.

The Amiga has 5 SIMM sockets, one socket reserved for chip RAM. I have removed this 2 Mb RAM and tried to put the other SIMMs in this socket. They fit, but Amiga doesn't boot, it gives me yellow colour, which is ok I guess. The funny thing is that I can't insert this 2 Mb SIMM into any other socket neither. I think that the problem is that the SIMMs come with double sided chips and the chips on the back of the SIMM card are being blocked by the neighbour's socket.

Any advice? Is it possible to use only single sided modules? Also, is it possible to use more that 4 Mb SIMMs? Some pages claim that the max is 4 Mb, yet some suggest that even 16 Mb module is possible!

Thanks!

[nex4060]

the 2MB "chip" memory only works in the first socket (the one closest to the zorro slots).

If you are using 8MB simms you can only insert 2 modules (max 16MB fast) and you will have to skip a socket. I don't remember witch socket to be populated, but i do know you have to skip one, hence: (socket 1:8MB 2:none 3:8MB 4:none 5:2MB chip) yeah i know the socket numbering might be wrong so dont lynch me :-)

btw: yellow screen means chip ram error as i recall

[b00mer]

Yes, I know that 2 Mb works only in the first socket, but I am talking about (physically) pluging memory module into a socket. I can't plug any memory module in other than "chip mem" socket, while all are pluggable in "chip mem" socket. Is there some special technique required to plug memory module to "fast mem" sockets?

Do I need to use single sided (no chips soldered on the back of the board) modules?

[patrik]

@b00mer:

If you are to use double-sided 8MB simms you will only as mentioned be able to use two of them. They should be inserted in the simm sockets labeled "bank 1" and "bank 2" - leave one simm socket empty between the Chip memory simm and the first 8MB simm, then leave another empty simm socket between the first 8MB simm and the second 8MB simm.

The reason for having to leave an empty simm socket between each simm is that the simm sockets spaced for single sided simms.

I also think you also have to set a jumper to use two double sided 8MB simms. I dont remember if it was Lemmink or Tjlazer who once mentioned which one that jumper was.


/Patrik

[dauber]

Reread b00mer's post -- at this point it's not so much a matter of whether 8-meg SIMMs will work, but that he can't actually FIT them in the fast RAM sockets; they'll only physically sit in the chip RAM socket.

b00mer -- are there little plastic tabs on the fast RAM sockets? I'm wondering if it's not so much that they don't FIT, but they don't HOLD...know what I mean? The Amiga 4000 motherboard RAM sockets are notorious for being extremely fragile. Got so bad that the SIMM holders on mine actually broke off, and if a SIMM got loose while I was working on something, my Amiga would freeze and refuse to boot. When I had my A4000 housed in a tower, they actually had to hot-glue the SIMMs in place so they wouldn't fall out.

BTW, the trick to fitting SIMMs in is sort of lining up the contacts with the socket, then sort of angling the SIMM back toward the motherboard, and you should hear a click sound.

If all else fails, it may be worth it to drop some money in an accelerator or a RAM expansion card so you can add some fast RAM without even dealing with the motherboard.

[patrik]

@dauber:

Yeah, I saw that, that's why I adviced him to leave an empty simm socket between each simm - this as otherwise the neighbouring simm will be in the way of the circuits on the back side of the double sided simm, definately making it not fit. As you say, the A4000 simm sockets can be an arse when it comes to actually holding the simms, especially if the circuits on the simms are a bit on the thicker side. It might also be possible that the double sided 8MB simms have too big/many circuits making them interfere with sockets neighbouring their back side, even if they dont contain a simm.

The simplest thing would be to get 4 pieces of 4MB single sided simms as those will definately fit. A good idea is to get simms with as slim circuits as possible as it will make the simms "click" to place much easier. It should not cost much either.


/Patrik

[b00mer]

Patrik and douber,

Thank for your replies. There are still plastic tabs on both side of the socket. I know how to position the module, since I could put modules in "chip mem" bank and hear the click, but the other banks are giving me headache.

Seems I should really get hold of slimer (single sided) modules...