The hardest thing to find are faster 32Kx8 SRAMs
in the 600 mil (wide) 28 pin DIP package. The ERPOM above is a 600m
size and the SRAMs installed on this board are 300m. The Zip GSX board
is setup to hold either size with the addition of a proper socket. There
are adapters available for the using 300m chips in a 600m socket but
these would be thicker than the entire TWGS card and reach into the
next two slots over. Since space is not a luxury within the Apple IIgs
case this is not an option for most people. As you can see, spreading
the leads of the 300m package will reach, barely reach, but reach the
holes on the board. Since these are soldered chips you should have a
way to test these SRAMs thoroughly before assembling this project. To
give yourself some more reach, if you cut the 8K Chips out from the
TOP OF THE LEADS instead of at the base you can bend over the remaining
toward the center and solder to the top of these. I did not do it this
way, but rather I removed the chips entirely from the board. In the
lower left and upper right you will need to place some sort of separator
under the chip and right up to the edge of the holes in the board because
potential shorts due to exposed leads being so close to the board. There
are no vias in the area under the upper right SRAM so there is no worry
here.
|