Pioneer IS-21T Service Manual - Page 23

XC-IS21T 7. GENERAL INFORMATION 7.1 DIAGNOSIS 7.1.1 SEQUNCE AFTER THE POWER ON Note 1 : IC No. or P∗∗ without name indicate the pin No. of microcomputer. Standby states POWER ON Power is ON. P35 SYSPOWER : "H" Transmit the bus data. System bus communication (∗1) Transfer the system POWER ON. Initialize the LCD microcomputer. P4 LCD POWER ON : "H" P53 LCDRST : "L" RESET Starts the LCD communication (∗2) DECK control IC starts the data transfer. Microcomputer P28 VOLDATA P34 VOLCLK Transfer P75 EXPCE Note ; ∗1 : System bus communication P29 SYSCLK P46 SYSDATA P47 SYSREQ ∗2 : Starts the LCD communication P48 LCDCLK P49 LCDCE P50 LCDDATA ∗3 : Transfer the Function, Volume, BASS and TREBLE data to the volume IC. P27 VOLCE P28 VOLDATA P34 VOLCLK ∗4 : Initial setting of CD decoder IC P17 CDCLK P18 CDLAT P19 CDDATA ∗5 : Initialize the TUNER PLL IC P65 TXCE P66 TXODAT P67 TXCLK P68 TXIDAT Does CD door open ? No Is P9 and P10 at "H" level ? Yes P11 : "H" Close the CD door. Initialize the DECK. Perform the following process after one second after the POWER ON. Transfer the Function, Volume, BASS and TREBLE data to the volume IC. (∗3) Function : CD (∗4) Initial setting of CD decoder IC. P22 CDCONT : "L" Function : TUNER (∗5) Initialize the TUNER PLL IC. P64 TXPOW : "H" DECK Initialize Sequence MOTOR ON Does the DECK Head down ? (Is the MODE SW OFF ?) Check P79 MODE SW input is "L". Yes No Is three times ? Yes Retry it to two times. No 500 msec. solenoid is ON ? IC2601(BU4094) P12 is "H" Perform the following process after 3.9 seconds after the POWER ON. Release the system MUTE. P71 SYSMUTE : "H" The condition that MUTE is not released. • VOLUME : 0 • DECK Function : excepting PLAY MOTOR OFF IC2601(BU4094) P11 is "L" Perform the following process after 4.0 seconds after the POWER ON. Release the speaker relay. P70 SPCONT : "H" 57