14Mb board not working

[Jammer]

Hi there - I bought a 14Mb board for my Falcon and found it doesn't work. I've got a couple of 16Mb simms with it.
When plugged in the Falcon doesn't boot. Works Ok with 4Mb board.
Is there anyone here that maybe able to test, repair it for me ?
Thanks
Jammer

[exxos]

Hi there - I bought a 14Mb board for my Falcon and found it doesn't work. I've got a couple of 16Mb simms with it.
When plugged in the Falcon doesn't boot. Works Ok with 4Mb board.
Is there anyone here that maybe able to test, repair it for me ?
Thanks
Jammer

It would help if you put where you are in the world If you state the "make" of the board, even a image may help, and what SIMM you are using then it would help also.

[Jammer]

Mevagissey, Cornwall .....
I'll get some more info up tomorrow.
Thanks

[alexh]

The Atari Falcon requires a particular DRAM configuration to work.

With the one SIMM adapter I have, only one out of ~30 16Mbyte SIMMs would work.



The RAM chips on your SIMM need to be 4Mx4 and not the more common 2Mx8

[Jammer]

Here it is .....

http://www.mevagissey.net/atari/falcon%20ram.jpg

[Arne]

The upper SIMM ist the right type *174*. Same works on Magnum-TT cards.
If the 4MB SIMM runs on the card you may check the topmost address-line MA10: Pin 19 of the 30pin connector running to the SIMM contact, not just the soldering of the pin at the SIMM.
You set the jumper on the right hand side of the card to 16MB when trying to 16MB SIMM?

[atari_mark]

Here it is .....

http://www.mevagissey.net/atari/falcon%20ram.jpg

I have the same memory upgrade card in my Falcon, see (http://povcd.info/falcon.html), I bought it from the person in Poland who made them (well I think it was Poland). The 16MB SIMM in mine has no numbers on so all I can see are the numbers on the memory chips which are USA RY 9811, S4004LE1DJ 06. Not sure if that help but if you have a SIMM with the same chip in you could try that one.

[alexh]

Here it is .....http://www.mevagissey.net/atari/falcon%20ram.jpg

The top 16Mbyte SIMM is 4Mx4 and so should work.

But what I notice is that the TOP SIMM is EDO and the bottom 4Mbyte SIMM is FPM.

Am I right in saying that the bottom SIMM works as 4Mbytes?

It should not matter, but it might be worth trying a 16MB 4Mx4 SIMM which is FPM?

I will check at home tonight to see if the SIMM I used was FPM or EDO.

[alexh]

The top SIMM is the 16Mbyte EDO SIMM - 60ns and the bottom SIMM is the 4Mbyte FPM SIMM - 70ns

I'm 100% sure that a stock Falcon 030 with a 16MHz bus speed will work fine with 70ns rated DRAM.

Remember that the 70ns speed rating of an asynchronous DRAM is for the entire DRAM cycle. One clock cycle on a 16MHz Falcon is 62.5ns and a DRAM access is many falcon clock cycles.

[Arne]

I recently successfully tried a 16MB SIMM on my card and recognised yesterday that it's an EDO. So in general EDO doesn't mean it's not working. AFAIK it's far more important if the DRAMs do have a square memory matrix or not.
I found the attached PDF someplace on the I-Net. May gives you a guide.