Re: Ekco T221.
Hi John,
It's all very strange. Unplug the scan coils and the EHT goes up and the oscillator squegging stops.
Next, connect up the scan coils again and disconnect one of the wires to the scan coil socket, the fault returns even though the coils are in a sense fully disconnected.
In the T221 the two sections of the scan coils are series connected to the line transformer in the normal manner, one end to the boost rail and the other to a tapping on the line OP transformer. Where the set differs from others is that the width and linearity coils are connected between the two sections of the scan coils. This circuit arrangement was carried forward to the 1955/56 models including the T293.
From 1957 on the width control circuit was simplified consisting of a tapped resistor in the HT supply to the boost diode. Models T310 and T311.
DFWB.
|