Epson 4000 - Manual (Page 70)

6. When the chip is properly positioned, push down firmly on
both ends of the chip to make sure it is well-seated.
7. Repeat steps 4 through 6 for the other chip.
8. Replace any option cards you removed. See page 4-14 for
instructions.
9. Now run SETUP as described in Chapter 2 to enable your
system to recognize the increased memory.
Installing External Cache
You can install 64KB, 128KB, or 256KB of external cache on
your system.
To install 64KB of external cache, use eight SRAM, 28-pin,
8 x 8, 20ns DIP chips, and one 8 x 8, 20ns tag chip
To install 128KB of external cache, use four SRAM, 28-pin,
32 x 8, 20ns DIP chips, and one 8 x 8, 20ns tag chip
To install 256KB of external cache, use eight SRAM, 28-pin,
32 x 8, 20ns DIP chips, and one 32 x 8, 20ns tag chip.
For the cache memory to work properly, you must install chips
in the following configuration (each bank contains four cache
memory sockets).
Installing and Removing Options 4-23