Kenwood KRC-444D Service Manual

KRC-444D/L14CIRCUIT DESCRIPTIONFunction DescriptionThese keys are used to write and recall the preset memory.Each FM, MW and LW frequency can be stored into one key in memory independently.However, the number of available bands differ with the area designated by the initializing diode matrix, as follows:For the area only 2 bands are available: 6 stations X 2 = 12 stationsFor the area 3 bands are available: 6 stations X 3 = 18 stationsCorresponding to the preset key pressed, the “‘CH" indicator and‘’ =’ (channel number) are displayed on the LCD panel.These keys are used for automatic tuning. During auto tuning operation, when the SD switch is turned OFF, the frequencydisplayed at the time is kept on hold.In auto tuning mode, the auto tuning operation is continued even when the LOUDNESS, ME, NR, METAL-DX/LOC, orMONO-DOLBY key is pressed.When one of the other keys is pressed, the auto tuning operation is stopped, and the unit enters the operation of the keypressed.When the SEEK key is pressed again, the frequency before the SEEK operation is resumed.SEEK UP/DOWNThis key is used to select the function between DX/LOC — MTL.@ Inthe Radio mode:Each time the key is pressed, the LOC output pin and the “‘LOC”’ display on the LCD panel are inverted. When the “LOC”display on the LCD panel, high level signal is output from the LOC Out pin, and when it is not lit, low level is output.@ Inthe Tape mode:Each time the key is pressed, the LOC output pin and the ‘’MTL"’ display are invertedWhen the ‘’MTL” is displayed on the LCD panel, low level signal is output from the LCD Out pin, and when it is not lit, highlevel is output.By initialization when the power is turned on, high level signal is output.DX/LOC—MTLThis key is used for writing the preset memory. It is also used for adjusting the time on clock display.@ Frequency display:Used when writing a new frequency into the preset memory. When this key is pressed, the ‘’ME”’ is displayed on the LCDpanel, and lit for five seconds after the key is released. While the ‘‘ME” is lit, pressing one key (M1 to M6) stores thedisplayed frequency into memory corresponding to the key pressed.To cancel the preset memory, while the ‘‘ME” is lit, press any key other than ME, NE, METAL-DX/LOC, MONO-DOLBY, orLOUDNESS.@ Clock display:The ‘‘hour” and “‘minutes”’ can be adjusted by pressing the MD or MU key while pressing the ME key.After pressing the ME key, each time the MD key is pressed, the ‘‘hour’’ is advanced one by one. Pressing it for a half secondor more advances the time by 4 hours/sec continuously until the MD key is released. This operation does not affect the“minute” or “second” digits (they are not displayed during this operation).After pressing the ME key, each time the MU key is pressed, the ‘‘minute’’ is advanced one by one. Press it for a half secondor more advances the minute in 8 minutes/sec speeds continuously, until the MU key is released. The “second” is notdisplayed, however, it is reset to zero every time the “minute” is set. The ‘‘minute” adjusting does not affect the ‘hour’.(Hour” is not changed even when the “‘minute’’ exceeds 60.)(During clock display, pressing the ME key alone changes the display to frequency and ‘‘ME” is displayed. In this condition,pressing one of the preset keys (M1 to M6) stores the frequency into the memory corresponding to the key pressed.)This key is used to select the band.When Band A is “0” or ‘1°’ and Band B is ‘’O”’ (LW: Not available) . ..Each time this key is pressed, the band is changed in the order of FM — MW — FM...Used for Loudness select key.Each time this key is pressed, the loudness output pin and the ‘“‘LOUD” display on the LCD panel are inverted. When the “LOUD”is displayed on the LCD panel, low level signal is output from the Loudness pin and when it is not lit, high level is output.By initialization when the power is first turned on (rising time of VDD), “LOUD” is displayed and low level is output.LOUDNESS