NAD T744 - Technical Procedures and Parts; Special Functions and Waveforms

12
SPECIAL FUNCTION
FEATURE KEYS PRESS ON FRONT PANEL
RESET FOR AH VERSION VIDEO 6 + SOURCE UP
RESET FOR C VERSION VIDEO 6 + SOURCE DOWN
NTSC / PAL SELECTION VIDEO 6 + MEMORY
VFD ALL DISPLAY VIDEO 6 + TONE DEFEAT
AM FREQ. STEP AM/FM + FM MUTE
VERSION CHECK VIDEO 6 + TONE CONTROL
DETAILS & WAVEFORMS ON SYSTEM TEST & DEBUGGING
T89C51RB2 (U202) main clock is at 20MHz (X202)
T89C51RD2 (U201) main clock is at 20MHz (X201)
UPPER - +5V supply to KEYBOARD when power up
LOWER - RESET line (TCM810LENB713) when
power up
UPPER - OUTPUT ENABLE (pin 24) of EPROM
(W27C02) when changing SURROUND MODES
LOWER - CHIP ENABLE (pin 22) of EPROM
(W27C02) when changing SURROUND MODES
SCLK (pin 43 of CS49326)
LRCLK (pin 42 of CS49326)
MCLK (pin 30 of CS49326)
NOTE: The waveforms are based on software version V2.12.