1540/1541/1541A/SX-64 Parts Location Part Number Description 2016 2K x 8 bit Static RAM (short board) UA2-UB3 2114 (4) 1K x 4 bit Static RAM (long board) 325302-01 2364-130 ROM DOS 2.6 C000-DFFF 325303-01 2364-131 ROM DOS 2.6 (1540) E000-FFFF 901229-01 2364-173 ROM DOS 2.6 (1541) E000-FFFF 901229-03 2364-197 ROM DOS 2.6 rev. 1 E000-FFFF 901229-05 2364 ROM DOS 2.6 rev. 2 E000-FFFF 325572-01 64H105 40 pin Gate Array (short board) 6502 CPU 6522 (2) VIA drive Alps DFB111M25A drive Alps FDM2111-B2 drive Newtronics D500 1541B/1541C Parts Location Part Number Description UA3 2016 2K x 8 bit Static RAM UA2 251968-01 23128 ROM DOS 2.6 rev. 3 C000-FFFF UA2 251968-01 27128 EPROM DOS 2.6 rev. 3 C000-FFFF UC4 251828-02 64H156 42 pin Gate Array UC5 251829-01 64H157 20 pin Gate Array UC2 6502 CPU UC1, UC3 6522 (2) CIA UD1 * 251853-01 R/W Hybrid UD1 * 251853-02 R/W Hybrid drive Newtronics D500 * Not interchangeable. 1541-II Parts Location Part Number Description U5 2016-15 2K x 8 bit Static RAM U12 SONY CX20185 R/W Amp. U4 251968-03 16K ROM DOS 2.6 rev. 4 C000-FFFF U10 251828-01 64H156 40 pin Gate Array U3 6502A CPU U6, U8 6522 (2) CIA drive Chinon FZ-501M REV A drive Digital System DS-50F drive Newtronics D500 drive Safronic DS-50F