Here is a 512K SMD IC installed up-side-down (just right of center) where the old 128K chip was (or was the original chip smaller than that?) ...

...it works great. However, I still need to get the next version of the operating system (the socketed chip to the left of center) to take advantage of the larger internal memory size.

Here is a 32K cartridge upgraded to 1M using two SMD ICs (up-side-down on top of each other) and some logic (small chip up-side-down to the right - think it was a 7400) for address decoding...

...I am still having problems with this one. It seams the connector design does not allow for any solder at all around the edge connector of the cartridge. I may have to cut off the plastic parts of the connector and permanently solder the 1M cartridge to the main board. (Any one have a "good" memory testing program for the z88?)

Email: stuart@xnet.com