The RAM upgrade plugs over the MMU and SHIFTER. The DRAM is compacted on top of the MMU adapter PCB making the design ultra small and compact and does not require simms.
There is a jumper link which can be connected to a toggle switch to enable 1MB mode or 4MB mode. This gives maximum compatibility for ST software which will only run with 1MB RAM. If your shifter is not in a socket then you will need to unsolder the shifter to plug into the board.
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