FT980 faults
                      ============

NOTCH FILTER NOT FUNCTIONING CORRECTLY : This is a 455kHz Q-multiplier
circuit and is prone to drifting. Adjust L03 for correct notch frequency and
VR2 for depth. The setting of VR2 is very critical. These are both on the IF
unit.

RF FEEDBACK : See Yaesu mod sheets for various cures for this.

ERRATIC OPERATION OF SHIFT CONTROL : This could be accompanied by a change in
the indicated mode when the shift is operated. Suspect Q26 on the CPU control
unit (8255).

PTT INOPERATIVE : Check LIN AMP switch on the back panel is not in the wrong
position. Check Q01 (MC14572) on the REG unit.

NOISE ON RECEIVE : Check the marker switch is not halfway between on and off
as this can introduce digital noise to the receiver.

INCORRECT OPERATION OF THE VFO : If the VFO only changes frequency during
part of the VFO dial rotation, then check alignment of the photo-couplers on
the optical disc. These can be adjusted with the long screw which is clearly
visible - it should only require MINIMAL adjustment.

INTERMITTENT OR NO CW SIDETONE : If CW break in using the VOX also fails then
suspect X01 (6.8MHz) on the FSK unit.

GENERAL COVERAGE TX : There is a mod kit available for this.

OVERHEATING : Check fan control circuitry.

WIDTH CONTROL AFFECTS MODE SETTING : Check the uPC8255 chip in the control
unit which connects to the width control.


(Downloaded from GB7SYP)