The screen is only very faintly illuminated when
the set is switched on and only a very dim picture and no raster is visible. Also the picture is badly out of focus.
On advancing the brightness control, the heater of the e.h.t. rectifier dims and the timebase whistle
alters slightly. Adjusting the ion trap magnet does not affect the screen.
The tube has been tested and found to be in good order.-C. H. Bateman (Norwich, Norfolk). You should check the ion trap magnet by substitution as the appearance of the EY51 suggests
that the e.h.t. unit is providing adequate e.h.t. and
the tube is taking current.