U1: ATC 93LC46 (serial EEPROM)
U2: Hyundai 90C54-GB189 (OTP/mask microcontroller)—running at 14.7456MHz
U3: Phillips 74HC373D (octal D-type transparent latch; 3-state)
U4: Utron UT6164JC-15 (15ns asynchronous SRAM, 8K x 8)
U5: Motorola HC4066 (quad analog switch multiplexer) or a Phillips 74HC4066D (quad bilateral switch)
U6: TI 271C 04T DH10 (under foil wrap—)
U7: TI LM358 (dual general purpose operational amplifier)