Kenwood TK-780 Service Manual

Also see for TK-780 series: Programming instructions Instruction manual Service manual supplement Service manual Instruction manual

45TK-780ADJUSTMENTTest Mode Test Mode Operating FeaturesThis transceiver has a test mode.To enter test mode,press [B] key and turn power on. Hold [B] key until testchannel No. and test signalling No. appears on LCD.Test mode can be inhibited by programming. To exit testmode, switch the power on again. The following functionsare available in test mode.• Controls ("SFT" appears)[PTT] Used when making a transmission.[] Shift off.[A] FFSK 1200 bps and 2400 bps.[B] Shift off.[C] Compander function on and off.[D] Beat shift on and off.[CALL] Shift off.[Channel Up/Down] Shift off.[Volume Up/Down] Shift off.• Controls ("SFT" not appears)[PTT] Used when making a transmission.[] Monitor on and off.[A] Sets to the tuning mode.[B] Shift on.[C] RF power high and low.[D] Changes signalling.[CALL] Changes wide, semi-wide and nar-row[Channel Up/Down] Changes channel.[Volume Up/Down] Volume up/down.Note : If a [A], [B], [C], [D] key is pressed during transmis-sion, the DTMF corresponding to the key that was pressedis sent.• LCD indicator"SCN" Unused" " Lights at compander on."AUX" Unused."P" Lights at RF power low."MON" Lights at monitor on."SVC" Unused." " Lights at FFSK 2400 bps.• LED indicatorRed LED Lights during transmission.Green LED Lights when there is a carrier.• Sub LCD indicator"SFT" Appears at shift on. Frequency and SignallingThe set has been adjusted for the frequencies shown inthe following table. When required, re-adjust them follow-ing the adjustment procedure to obtain the frequencies youwant in actual operation.• Frequency (MHz)Channel No. RX TX1 160.05000 160.100002 146.05000 146.100003 173.95000 173.900004 160.00000 160.000005 160.20000 160.200006 160.40000 160.400007~16 – –• SignallingSignalling No. RX TX1 None None2 None 100Hz square3 QT 67.0Hz QT 67.0Hz4 QT 151.4Hz QT 151.4Hz5 QT 210.7Hz QT 210.7Hz6 QT 250.3Hz QT 250.3Hz7 DQT 023N DQT 023N8 DQT 754I DQT 754I9 DTMF DEC, (159D) DTMF ENC, (159D)10 None DTMF tone 911 2-tone (321.7/928.1Hz) None12 Single tone 1200Hz Single tone 1200Hz13 5-tone DEC. (EIA #12345) 5-tone ENC. (EIA #12345)14 – FFSK15 FFSK code FFSK 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 a4Ω dummy load and connected to an AC voltmeter and anaudio distortion meter or a SINAD measurement meter at alltimes during tuning. Transceiver Tuning(To place transceiver in tuning mode)Channel appears on LCD. Set channel according to tun-ing requirements.LCD display (Test mode)1n 1–Channel No.W/SW/N Signalling No.