This set incorporates teletext reception facilities. The
teletext display is good, but on picture the white goes out of
focus when a white line or letters or a very bright scene is
present. The whites are perfect if the contrast control is
reduced to a very low setting.
Set the a.g.c. preset control R318 for 3.3V ± 0.3V at the
anode of the tuner a.g.c. delay diode D2, with a test card F
input of about lmV. Then check the beam limiter circuit, by
confirming that the voltage at the cathode of D3 swings
from 0.8V to 3.2V over the range of the brightness control.
Finally, set the focus control R100 for optimum definition
of the highlights.