INVICTA 126

The picture tends to have wavy verticals. This trouble occurred when the picture lacked width. Replacement of the metal rectifier remedied the
width, but still the wavy verticals were present. Could you please help me to locate this fault ? -G. Fryer (Newcastle).
We have found the wavy verticals are caused
by the improper contact between a chassis tag and
the chassis. This tag is riveted and carries the
heater return lead as well as the cathode corn – ponent chassis connections of the PCF80 (line
oscillator) valve. The tag should be well soldered
to chassis or a thick lead taken to another chassis
tag. The waviness is due to hum being induced
into the PCF80 circuit by the poor contact.