Service manual

Focus
1. Tune the set to a circle or crosshatch test pattern (use an external video pattern
generator).
2. Adjust the first Focus potmeter (upper LOT potmeter, see figure 8-1) until the
horizontal and vertical lines at 1/4 from east and west, at the height of the
centerline, are of minimum width without visible haze.
3. Adjust the second Focus potmeter (middle LOT potmeter, see figure 8-1) until the
horizontal and vertical lines at 1/4 from north and south, at the height of the
centerline, are of minimum width without visible haze.
PIP AGC adjustment
The Automatic Gain Correction adjustment prevents overdriving of the PIP-tuner if the
aerial signal is too strong. Overdriving is visible as a loss of color and synchronization in
the PIP picture. Amplification has to be adjusted to minimum level, but the PIP-picture
should be as free of noise as possible.
Adjustment
1. Connect a pattern generator to the PIP tuner.
2. Select color bar without sound and apply a strong aerial signal of 4mV (72dBµV)
and set frequency for NTSC to 61.25MHz.
3. Connect an oscilloscope to the output of the PIP tuner (pin 11).
4. Adjust potentiometer R3942 so that the oscilloscope indicates 0.5Vpp.
5. If an aerial signal is not available, adjust R3942 to 30% of its total travel (100% is
fully left).