520 STFM C070523-001 Rev D RAM Upgrade

[ChrisA]

Hi

I'm looking to upgrade the RAM from 512 to 1MB. On the main pcb I see what I think are 16 RAM slots free (from U46 - U61) arranged horizontally above the existing RAM chips.

You also offer a 16 chip upgrade but for main pcbs later than mine as seen here:
https://www.exxosforum.co.uk/atari/last/ram/index.htm

I don't want to modify the ST much as is required by some of the other RAM upgrades and so was wondering if I could get the RAM chips I need for here? If not does anyone know where I could get them?

Thanks.

Here's a picture of my PCB for reference.

IMG_9254.jpg (846.01 KiB) Viewed 1032 times

No there isn't - apparently you can't upload images - Ohhh yes there is - when you do it properly (thanks)

[olivier.jan]

Hi,
Yes the RAM chips are the same, just placed in a different location on the motherboard.
So as long as you get 16 x 41256 chips and capacitors (original were 0.22uF) it should be fine. You will also need to add the missing resistors.

[rubber_jonnie]

Here's a picture of my PCB for reference.


No there isn't - apparently you can't upload images

Add your image in the attachments tab and the place it inline.

[exxos]

16 chip ram chips, through hole.

https://www.exxosforum.co.uk/atari/store2/#0111

[ChrisA]

Here's a picture of my PCB for reference.


No there isn't - apparently you can't upload images

Add your image in the attachments tab and the place it inline.

Thanks - I added a photo of the PCB.

[ChrisA]

Hi,
Yes the RAM chips are the same, just placed in a different location on the motherboard.
So as long as you get 16 x 41256 chips and capacitors (original were 0.22uF) it should be fine. You will also need to add the missing resistors.

Thanks, that's great news. I assume the "missing resistors" is detailed on the upgrade page.

[olivier.jan]

Actually from the picture you posted the resistors seems to be already installed on this motherboard.

[Icky]

Looks like the empty chip holes have solder in them, that's going to be a pain to desolder. I recommend getting a desoldering gun. It takes away a lot of the pain of desoldering.

[rubber_jonnie]

Actually from the picture you posted the resistors seems to be already installed on this motherboard.

Yeah, I thought the same.

[ChrisA]

Looks like the empty chip holes have solder in them, that's going to be a pain to desolder. I recommend getting a desoldering gun. It takes away a lot of the pain of desoldering.

Thanks I already have one. It will be handy here for sure.