Control board MA-291: main chips and battery
The MA-291 control board runs on an R6502 CPU at U1 (XO-360) with a 3.579545 MHz crystal (XO-456), program ROMs at U2 and U3, three R6532 RIOT chips at U4 to U6 (XO-361) and a 5101 static RAM at Z5 (XO-356) for bookkeeping. Memory is kept by a 3.6 V battery at BAT1 (XO-458). The DIP switches SW1 to SW4 are XO-505.
Systems
Related tips
- How System 80A differs from System 80
- System 80 control board chips
- System 80 CPU board main chips
- Buffer chips protect the control board LSI parts
- Control board clock frequency
- Control board power-on checks
- Key pins on the System 80 LSI chips
- Use exact chip types in the CPU clock circuit
Source: Premier Technology Parts Catalog (System 80, 80A and 80B), Gottlieb / Premier