FT480 faults ============ DISTORTION ON SSB TX : Check PA. If there is no O/P in FM low power position then PA is very suspect. NO RF O/P WHEN HOT : Check PA. NO LOW POWER FM TX : Suspect PA. LOW SENSITIVITY RX : Check RF stage - if this is OK check Ae i/p coil T01 for o/c. See next fault. INTERMITTENT TX AND RX : Check TX/RX 8v. switching relay. Check 10.24MHz xtal in PLL. LOW POWER TX AND/OR POOR RX : Check relay and xtal as above. FLUCTUATIONS IN OUTPUT POWER : Check PA. Check relay and xtal as above. Also check the power control transistor Q03 in the PA screened box. RX FAILS WHEN PTT RELEASED : Check TX/RX 8v. switching relay. ERRATIC FREQUENCY SHIFTS : Check X02 63.9151MHz xtal in PLL. ERRATIC OPERATION OF TUNING CONTROL : Step switch. SUDDEN JUMPS IN FREQUENCY WHEN TUNING IN SSB : X02 - as above. NO AUDIO : Check audio output IC. DISPLAY ON WHEN UNIT TURNED OFF : Check D34 on the microprocessor control board. INTERMITTENT AUDIO ON TX : Check the mic gain and deviation presets as these can become dirty/cracked. TONE CALL BUTTON APPEARS INOPERATIVE : Many owners have disconnected this button and used it to provide a 'listen on input' facility. STRANGE FREQUENCY READOUT : Check microprocessor, especially if one digit is brighter than the rest. ALL EIGHTS ON FREQUENCY DISPLAY : DC power applied to rig when rig is switched on - this problem can be alleviated by changing C01 - the power-up reset cap (on control unit, connected to pin 24 of microprocessor) to a larger value (0.47uF tantalum). Also check microprocessor. (Downloaded from GB7SYP)