Atari 520 ST memory upgrade

With 2 new working Atari ST 520 FMs, see previous blog, I decided to upgrade the RAM to 1024K from the original 520K. Both machines had completely different motherboards, one with through hole memory chips, the other with surface mount. For some reason I decided to start with the most difficult……with the surface mount chips :(. It was the in the best condition, and looked like the later revision.

The next tricky things was locating the 4 bit * 256 chips needed for the upgrade – these things are never easy. I headed to EBay, but couldn’t find anything suitable. After lots of searching I stumbled across a listing for some memory sticks with the right chips.

Memory sticks with chips removed

My first attempt was with my new hot air station – which didn’t go well – I obviously need some practice. The result was a lifted pad on one of the chips. I decided the safer options was to use my TS100 micro soldering iron with it’s finest tip. After a couple of hours of tricky soldering and checking connections I had all four chips installed, and one bodge wire for the missing pad.

New memory chips installed in Atari 529 ST FM

To check that they were working I booted the Atari SysInfo software – 1024K – success.

Next a Gotek upgrade for the floppy.