exxos's Atari, Amiga & retro forum

Evening Exxos,

Decided to go for the 4MB ram expansion of yours and it arrived today.

Unpacked and examined.. couple of questions.

1. Is this pin meant to be like the photos below? If so, why?

2. Do I need the R71,72 & 73 in place? May have damaged the pad on the bottom of the board so if not needed less work on my behalf :lol:

3. Do I still need to swap out the 10K resistor if I fit a switch?

Many thanks team

Eddie

eddieallsopp wrote: 05 Aug 2025 18:54 1. Is this pin meant to be like the photos below? If so, why?

I probably thought at some point, hey wouldn't it be incredibly useful just to have a header pin there so I could test the boards without having to solder a wire onto every single board and then have to remove the solder again afterwards...

2. Do I need the R71,72 & 73 in place? May have damaged the pad on the bottom of the board so if not needed less work on my behalf :lol:

Yes you need to resistors in place otherwise they'll be disconnect between the MMU and RAM..

3. Do I still need to swap out the 10K resistor if I fit a switch?

if you are fitting the switch you need to change the resistor otherwise you will have the issues as mentioned on the install page...

Have a look at the install page towards the bottom..

https://exxosforum.co.uk/atari/last/4mb/index.htm

Thanks for the quick response matey. Regarding the pin, just wanted to make sure the delivery of kicking it over my fence had damaged it. lol. Seriously was just wondering and now I know.

Yeah, I read the instal several times prior to ordering and just wanted to make sure. Don't want to make the ST more poorly than she currently is :D

Yours aye

Eddie

Hi All,

Just an update.

Exxos, and team if there is one, you are geniuses. Hardest part of the install was removing the old memory and unsoldering the holes to fit the new board.

All fitted and singing. I now have a 4MB STFM running with a sidecart multi device.

Next project is the build of the ACSI2STFM board and then I feel that my ST has reached the full potential that I want to get it to.

Great work and please, keep it up.

Thanks for all the help.

Yours aye

Eddie

Well done!

Not many manage to install stuff without screwing everything up. Badly.

:2k2:

eddieallsopp wrote: 14 Aug 2025 06:47
Next project is the build of the ACSI2STFM board and then I feel that my ST has reached the full potential that I want to get it to.

Have you already got the parts for one? I have a spare bare PCB hanging around which you can have for free.

elterwater wrote: 14 Aug 2025 21:36

eddieallsopp wrote: 14 Aug 2025 06:47
Next project is the build of the ACSI2STFM board and then I feel that my ST has reached the full potential that I want to get it to.

Have you already got the parts for one? I have a spare bare PCB hanging around which you can have for free.

I have matey. Bought them off JLCPCB. Built 1 and now just sorting it out with drivers and stuff.

Taken me a few days to get my head around some of the routines to do but, after the amazon delivery this afternoon, she is flashed and now the drivers bit to do.

I did fit the SidecarT TOS emulator and decoder whilst taking a break from the ACSI2STFM build..that was a bit emotional :D :D :lol:

Hello.

I've not been able to find a list of parts in the ATARI STFM 4MB RAM EXPANSION kit.

Whats in the kit please?

It'll be fitted to a 520/1024 C070789 Rev D board.

Is there anyting else needed not in the kit.

thanks.

You just solder the board in pretty much.. You can get a switch as a option.. That's about it.

You just solder the board in pretty much.. You can get a switch as a option.. That's about it.

So everything required is supplied ready to solder in ?

We don't see many Atari machines,its for a customer that is already asking when its coming back.
So a little nervous of ordering someting that needs something else too.