Murphy 659X: No Raster

Investigations in the line output circuit revealed that there was a weak “r.f.” spark at the anode of the U26 e.h.t. rectifier.With the top caps removed from the line output and boost rectifier valves, the boost reservoir was tested for short-circuit, with negative result.

It transpired eventually that this capacitor had gone open-circuit, but at first no test was made to check this.It is very common to find the boost capacitor short but rare to be open.