A4000 RAM question

Hello. I've recently aquired an A4000 which was being chucked out at work. At the moment it has 2 sticks of RAM installed. One is the standard 2mb chipram and the other is 4mb. My question is what is the best option for upgrading the RAM? Can I just drop a 16mb SIMM instead of the 4mb one, or is it best to have 4 separate 4mb sticks?

Also, will this type of RAM work with the 4000?
http://cgi.ebay.co.uk/Amiga-1200-4-m...QQcmdZViewItem

Thanks in advance

[Jope]

Hi, this should have been in prb.hardware.

4 separate 4MB sticks is the surest way to upgrade the machine, some A4000s are also reported to work with two 8MB SIMMs, but those need to be installed leaving one empty slot between them.

My suggestion: get a Phase5 accelerator and plug in more and faster RAM and forget the motherboard SIMM slots. :-)

Thanks for the quick reply. I'll probably order some 4mb simms for now, and look into getting an accelerator later

[Methanoid]

Originally Posted by spoonatron

Hello. I've recently aquired an A4000 which was being chucked out at work.

Lucky git... sell it to me now

[BinoX]

If these are the ram slots:

-------- (CHIP)
-------- (Bank 1)
-------- (Bank 2)
-------- (Bank 3)
-------- (Bank 4)

Here are the possible combos for 16MB(with 2MBCHIP RAM):

-------- 2MB, 2MB, 2MB, 2MB
-------- 4MB, None, 4MB, None
-------- 4MB, 8MB, 4MB, 8MB
-------- 4MB, None, None, 4MB
-------- 4MB, 8MB, 8MB, 4MB

My config is the 2nd column and it works fine...
Using larger sims in the slots works too but they will be limited to either 4 or 8mb depending on how you put them in.

Thanks to everyone who replied. I bought 3 4mb SIMMS from Amiga Deals on ebay, and they arrived the next day
My A4000 now has 16mb of fast RAM to play around with.

[cugar124]

Hey Guys
My 4000 only sees the 1st 1meg of each simm has anyone ever seen this. Also would two 4mb ram sticks in slots 2 and 4 be seen as 8mb?


Ive had new simm sockets put on the board and the traces checked its driving me

[FOL]

Originally Posted by cugar124

Hey Guys
My 4000 only sees the 1st 1meg of each simm has anyone ever seen this. Also would two 4mb ram sticks in slots 2 and 4 be seen as 8mb?


Ive had new simm sockets put on the board and the traces checked its driving me

So, if you have only one in, it only sees 1mb?
If so, then have you tried other simms from the ones you are using?

[cugar124]

Yeah I'm on my third set of simms

Sent from my Z1 using Tapatalk

[FOL]

Originally Posted by cugar124

Yeah I'm on my third set of simms

Sent from my Z1 using Tapatalk

What happens, if you remove them all and try them as chip ram. I wouldnt expect all to work, however if they show as 2mb, you can rule out simms 100% and look elsewhere.

[Daedalus]

Just bear in mind that single rank SIMMs (usually single-sided) will only show up as 1MB in the chip RAM slot, and this is normal.

[hooverphonique]

Originally Posted by cugar124

Also would two 4mb ram sticks in slots 2 and 4 be seen as 8mb?

no, when using 4mb simms, you need to put them next to each other (fastram socket 0 and 1). Only use every other slot when using dual-rank simms (2mb, 8mb, 32mb, etc).

[grelbfarlk]

Originally Posted by cugar124

Hey Guys
My 4000 only sees the 1st 1meg of each simm has anyone ever seen this. Also would two 4mb ram sticks in slots 2 and 4 be seen as 8mb?


Ive had new simm sockets put on the board and the traces checked its driving me

Have you checked the obvious thing, that the jumper J852 is set for 256K x 32?



This can also happen if you have poor grounding or some other power issue, or one of the address lines is shot. I have this ATX power supply adapter and of the 64MB on the motherboard, depending on what power supply I plug into it, I can get anywhere from 16MB to the full 64MB.

[A4000Bear]

Originally Posted by cugar124

Hey Guys
My 4000 only sees the 1st 1meg of each simm has anyone ever seen this. Also would two 4mb ram sticks in slots 2 and 4 be seen as 8mb?


Ive had new simm sockets put on the board and the traces checked its driving me

This is a common problem caused by battery leakage damaging some of the TTL logic chips that controls the fast RAM. I have repaired a few A4000s with this problem. If my memory serves me correctly, you can try replacing U891, which is a 74F245.

[cugar124]

Does that chip need to be programmed pleas?

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[Daedalus]

The 74F245? No, it's a standard logic chip, albeit a slightly more unusual variety.

[nogginthenog]

I'm pretty sure my first A4000 had this problem. I wasn't too bothered because I has 128Mb on a CPU card. That A4000 needs a recap. Not enough time..

[grelbfarlk]

Originally Posted by cugar124

Does that chip need to be programmed pleas?

Sent from my VS988 using Tapatalk

Randomly suggesting replacing parts is not really a good idea. How about some high resolution pictures of the motherboard, both sides and some closeups of the RAM area and near the battery? Then maybe people can give you better suggestions.

[cugar124]

Hey guys as requested one side

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[cugar124]

Board has been recapped and new simm sockets done

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