Kenwood FM Transceiver TK-481 Service Manual

Also see for FM Transceiver TK-481: User manual Instruction manual Specifications Instruction manual Service manual

34TK-480/481 ADJUSTMENTTest Mode Test mode operating featuresThis transceiver has a test mode.To enter test mode,press [A] key and turn power on. Hold [A] key until testchannel No. and test signalling No. appears on LCD. Testmode can be inhibited by programming. To exit test mode,switch the power on again. The following functions are avail-able in test mode.• ControlsControls “FCN” appears “FCN” not appears[PTT] Used when making a Used when makingtransmission. a transmission.[AUX] Unused Unused.[MON] Monitor ON and OFF. Monitor ON and OFF.[LAMP] Lights the lamp for five Unused.seconds.Lighting is extended fora further five seconds bypressing any key whilethe lamp is lit.[S] MSK 1200 bps and Sets to the Tuning2400 bps mode.[A] Function OFF Function ON.[B] Compander function RF power HIGH andON and OFF. LOW.[C] Beat shift ON and OFF Changes group.[0] to [9], Used as the DTMF Used as the DTMFand [#], keypad. If a key is keypad. If a key is[ *] pressed during trans- pressed during trans-mission, the DTMF mission, the DTMFcorresponding to the corresponding to thekey that was pressed key that was pressedis sent. (keypad model) is sent. (keypad model)[ENCODER] Changes system. Changes system.Note : If a [S], [A], [B], [C] key is pressed during transmis-sion, the DTMF corresponding to the key that was pressedis sent.• LCD indicator“SCN” Unused“ ” Lights at Compander ON.“LO” Lights at RF Power Low.“P” Unused“MON” Lights at moniter ON.“SVC” Unused“ ” Lights at MSK 2400 bps.• LED indicatorRed LED Lights during transmission. Blinks at thelow battery voltage warning.Green LED Lights when there is a carrier.• Sub LCD indicator“FCN” Appears at Function ON. Frequency and signallingThe set has been adjusted for the frequencies shown inthe following table. When required. re-adjust them followingthe adjustment procedure to obtain the frequencies youwant in actual operation.Frequency (MHz)SYS No. TK-480 TK-481RX (TX : TA) TX RX (TX : TA) TX1 851.0500 806.0500 935.0250 896.02502 851.5500 806.5500 935.0500 896.05003 860.0000 815.0000 938.0000 899.00004 860.5000 815.5000 938.0250 899.02505 865.9875 820.9875 939.9875 900.98756 869.4000 824.4000 940.4000 901.40007 869.9000 824.9000 940.9000 901.90008 855.4000 810.4000 936.2500 897.25009 865.6000 820.6000 939.3000 900.300010 867.5000 822.5000 936.7500 897.750011~16 – – – –SignallingGroup No. RX TX1 None None2 None 100Hz square3 LTR data LTR data4 QT 67.0Hz QT 67.0Hz5 QT 151.4Hz QT 151.4Hz6 QT 210.7Hz QT 210.7Hz7 QT 250.3Hz QT 250.3Hz8 DQT D023N DQT D023N9 DQT D754I DQT D754I10 DTMF DEC, (159D) DTMF DEC, (159D)11 None DTMF tone 912 None None13 Single tone 1200Hz Single tone 1200Hz14 None MSK15 MSK code MSK code• Preparations for tuning the transceiverBefore attempting to tune the transceiver, connect theunit to a suitable power supply.Whenever the transmitter is turned, the unit must beconnected to a suitable dummy load (i.e. power meter).The speaker output connector must be terminated with a16Ω dummy load and connected to an AC voltmeter and anaudio distortion meter or a SINAD measurement meter at alltimes during tuning.