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Video CN4215: Field Sync Loss
Now that these receivers are ageing, a fault resulting in the complete loss of field sync. Although there is no field hold, the sync circuits behave quiet normally, and no fault can be found in the field timebase circuit. This fault has been found to be caused by the failure of the 100uF electrolytic by-pass capacitor in the cathode circuit of the video amplifier ( C27 in Trader sheet 1069) which effects the low frequency response.