My personal SYM-1 system.
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My current SYM contains 58K of RAM, 5K of ROM, and the last 1K (decoded down into $80 byte blocks) is for I/O. The memory map located here. shows the complete mapping. The first picture shows the SYM boards installed from the front with the keyboard and display panel removed. Bottom board is SYM, 2nd board is 48K Ram, and top is floppy controller. Small board to right is power converter. Below converter board is battery for RTC.
SYM fully assembled minus top cover. Shows second homemade version of Synertek KTM-2/80 terminal. SYM is located behind display.
SYM main board. This board contains 1 - 6502, 2 - 6532's, 2 - 6522's, MSM5832 Real Time Clock, 10K RAM ($C000 - $DFFF & $F000 - $F7FF) & 2 - switch selectable page $E, MON 1.1 EPROM'S with one being original (except being relocated to $E page) and one special which sends control to the boot ROM after power up. The board breakdown is located here.
48K RAM card with memory from $0000 to $BFFF. This board contains both address and data line buffers as well as address decoders.
Converter board. Supplies -5 & +12 from DC to DC converter for floppy controller and also contains +25V power supply for EPROM programmer.
Two - 5 1/4" 80 track drives.