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.
No there isn't - apparently you can't upload images - Ohhh yes there is - when you do it properly (thanks)
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520 STFM C070523-001 Rev D RAM Upgrade
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ChrisA
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520 STFM C070523-001 Rev D RAM Upgrade
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olivier.jan
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Re: 520 STFM C070523-001 Rev D RAM Upgrade
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.
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.
Retro stuff
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
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rubber_jonnie
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Re: 520 STFM C070523-001 Rev D RAM Upgrade
Add your image in the attachments tab and the place it inline.ChrisA wrote: 02 May 2026 23:27
Here's a picture of my PCB for reference.
No there isn't - apparently you can't upload images
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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exxos
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ChrisA
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Re: 520 STFM C070523-001 Rev D RAM Upgrade
Thanks - I added a photo of the PCB.rubber_jonnie wrote: 03 May 2026 07:20Add your image in the attachments tab and the place it inline.ChrisA wrote: 02 May 2026 23:27
Here's a picture of my PCB for reference.
No there isn't - apparently you can't upload images
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ChrisA
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- Posts: 21
- Joined: 02 May 2026 23:12
Re: 520 STFM C070523-001 Rev D RAM Upgrade
Thanks, that's great news. I assume the "missing resistors" is detailed on the upgrade page.olivier.jan wrote: 03 May 2026 05:51 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.
-
olivier.jan
- Site sponsor
- Posts: 337
- Joined: 01 Jun 2020 08:00
Re: 520 STFM C070523-001 Rev D RAM Upgrade
Actually from the picture you posted the resistors seems to be already installed on this motherboard.
Retro stuff
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
-
Icky
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Re: 520 STFM C070523-001 Rev D RAM Upgrade
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.
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rubber_jonnie
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- Posts: 14728
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- Location: Essex
Re: 520 STFM C070523-001 Rev D RAM Upgrade
Yeah, I thought the same.olivier.jan wrote: 04 May 2026 00:21 Actually from the picture you posted the resistors seems to be already installed on this motherboard.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
-
ChrisA
- Site sponsor
- Posts: 21
- Joined: 02 May 2026 23:12
Re: 520 STFM C070523-001 Rev D RAM Upgrade
Thanks I already have one. It will be handy here for sure. :-)Icky wrote: 04 May 2026 08:41 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.
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