4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)

jwd · Post by **jwd** » Sun Sep 13, 2026 5:56 pm

A good video upgrading exactly this type of memory chips

I have it bookmarked as I'll be doing this on mine at some point, i got the chips from a 4mb falcon memory board as the chips were marked the same as in my ST.

You really need a diag cart and see what the output is via serial probably one or more chips not right.

MaximilianM · Post by **MaximilianM** » Mon Sep 14, 2026 9:31 am

ah thx nice video, and yeah i conntacted my local dealer, maybe he has a diagnostic card... without its pain in the ass...

MaximilianM · Post by **MaximilianM** » Sat Sep 19, 2026 2:31 pm

Quick update: got the Atari Bombs Away diagnostic cartridge and tried it. Instead of the expected diagnostic menu, I get a different error pattern on screen — static vertical color bars, not the usual half-black/half-noise I had before. Reset button does nothing while the cartridge is plugged in (works fine again once I pull it).

Does anyone know which RAM bank or which specific RAM IC is tied to the video/screen memory on the 1040 STFM? Trying to narrow down which chip to focus on. Thanks!

DoG · Post by **DoG** » Sat Sep 19, 2026 4:27 pm

Connect with another computer via null-modem-cable to get output from diagnostic cartridge. RS232-USB to PC for example also work with a terminal program.9600 baud,8N1 (8 data bits, No parity, 1 stop bit). No flow control

https://www.atari-wiki.com/index.php?ti ... dge_basics

(Then the basic: clean port and cartridge with isopropanol, set 'bombs away' to (mega) ST 4.4)

exxos's Atari, Amiga & retro forum

4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)

Re: 4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)

Re: 4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)

Re: 4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)

Re: 4MB RAM upgrade for C103414-001 Rev 1.1 (520/1040 STFM)