Even though you shouldn't damage your machine if you know how to solder and follow the few simple precautions described below, you may want to wait until your warantee period is over. Is anyone still there? I don't want to sound overly pessimistic, it is a straightforward job.
One thing you should be aware of while working inside your computer, components inside the B128, and the memory ICs used in this project are static sensitive. While handling the circuit board or the ICs you should ground yourself.
To perform the memory expansion we cleared the solder from all the component holes required then installed sixteen low profile 16 pin sockets into IC locations U29-U36 and U45-U52. Also installed at this time were 16 .22uf disc capacitors, C66-C73 and C94-C101, and two 22uf pc mount electrolytic capacitors C65 and C93. The B128's pc board has very good component legends so there shouldn't b any problem finding the component locations. After soldering all the previously installed components in place we inserted sixteen 4164 200ns 64k x 1 dynamic ram ICs into the newly installed sockets, being careful to orient pin 1 of the ICs to the top left of the circuit board.
After re-assembling your B128 connect it up and turn it on. Don't be alarmed if it takes several seconds to display the initialization message. Every time you turn on a Commodore computer it does a test of available ram automati lly. If everything went well during the installation it should have twice as much ram to test! If you don't get the normal message after a minute or so you have a problem, see the suggestions that follow. Once you get the BASIC prompt display you should enter the machine language monitor by typing:
sys6 <RETURN>
The monitor will prompt you by printing a period. Type the following:
m 0355 <RETURN>
The monitor will display the address, 0355, followed by 16 bytes expressed as 2 digit hexadecimal numb s. The first three of these should be 'ff fb 04' the important number is '04' indicating the top bank of 64k as detected by the ram test. Anything less than '04' suggests you have a problem. The number usually found at this location in an un-expanded B128 is '02'.
You should know that BASIC will not use the expansion memory for program text or variables, except that by using the 'bank' statement you may peek and poke values there, and 'bload' and 'bsave' can be used to transfer data from these banks t and from disk. Superscript II will use the expansion ram however, giving you the capability to have 3 files loaded at the same time. You can also use this new memory space for large machine language programs of your own.
