Pattern 4 : "Greyscale" - Philips PM 5508 Operating Manual

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D. Pattern 4.
"GREYSCALE"
Fig. VII-7. "GREYSCALE"-pattern
This greyscale signal is a linear staircase signal. It has not been derived
from the colour bar signal by removing its chroma-information.
1. • Check the proper functioning and the range of the brightness and
contrast controls of the receiver. !n some receivers the black level
is kept constant and is not effected by operation of the contrast
while each of the 6 steps in between should show an equel increase
of grey (from left to ,right).
2. • Check the proper greyscale setting of the colour receiver. The
various greybars should not contain any colour. (If the greyscale
setting is not correct, the ratio between the beam current and the
control grid curves of the three guns of the picture tube is not
constant; re-adjust according to the instructions in the Service Notes
of the relevant receiver).