B&K 1076, Инструкция по эксплуатации, Страница: 29 / 64

plate of this stage. In essence, then, we can completely bypass the horizontal
output tube. A second innovation is two indicator lights which further serve
to pin-point troubles in the output transformer, or the high voltage network.
The lights operate on a "go - no-go" basis, clearly revealing to the serviceman
the presence or absence of certain hard-to-find troubles.
And last, but not least, sensitive leakage and shorted-turns tests can be
made quickly and conclusively on yokes and horizontal output transformers,
again providing the user with positive information.
Let us assume the receiver under test has no picture or raster and there is
an absence of high voltage.
1. In order to determine whether the' defeat lies in the horizontal oscil­
lator stage or the horizontal output amplifier and the stages following
it, proceed as follows:
Using the Horizontal Grid Drive pulse available from. the front
panel of the TV Analyst apply this signal to the grid of the hori­
zontal output tube. Connect the high voltage indicator lamp to the
insulated wire going to the plate cap of the high voltage rectifier
tube and remove the plate cap from this tube. See Fig. 15. Apply
power to the receiver under test and observe the high voltage in­
dicator lamp.
6 BQ6
H.V. INDICATOR CLIP
ON INSUL ATED PORTION
HORIZONTAL
OUTPUT
TRANSFORMER
Figure 15-Connecting High Voltage Indicator
If the lamp glows this indicates the presence of high level R.F.
pulses on this lead. Turn off the power and reconnect the high
voltage plate lead to the rectifier tube and again apply power. If
the high voltage rectifier circuit is 0.K., the lamp should still remain
lit and hi voltage should be present and deflection will be observed
on the face of the CRT. Since the application of a driving pulse to
the grid of the horizontal output resulted in restoring operation to
the receiver the trouble definitely lies in the horizontal oscillator
circuit. A few voltage and resistance checks will certainly bring the
trouble to light.
Let us take another case where no hi voltage is again the trouble.
Application of grid driving pulses do not restore hi voltage or deflec­
tion. This indicates that the trouble is not in the horizontal oscil­
lator but that the difficulty lies in the output circuit of the receiver.
Turn the Plate Drive Selector switch of the Television Analyst to
the Horizontal position. Connect the ground lead of the instrument
to chassis ground or B- and connect a test lead from the Plah
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