Philips PM 3342 Manual page 11

14
Push-button By depressing this button the input circuit
CHECK is interrupted and the amplifier input is
ZERO earthed, so that the zero level can be
(SKl; SK7) checked.
Double With this double knob the deflection
knob V/cm coefficient of the amplifier can be adjus-
(R3; RS)
ted.
The deflection co-efficients are calibrated when the
continuous control is turned fully clockwise (position
CAL.).
Polarity switch SK2 & SK8
SHIFT knob Rl & R7
GAIN control R4 & R6 (screw-driver adjustment)
DC BAL. control R2 & R8 (screw-driver adjustment)
"NORM." : a positive-going input signal causes an
upward deflection on the screen.
"INVERT.": a positive-going input signal causes a
downward defection on the screen.
With this knob the trace can be shifted in Y-direction.
The working-direction of this SHIFT knob is depen-
dent o~n the position of the polarity switch.
The deflection coefficient of the amplifier can be
checked by applying the calibration voltage of the basic
oscilloscope to the input socket.
If the deflection coefficient does not correspond to the
indicated value, it can be corrected by adjusting the
GAIN control. In this case the continuous V/cm con-
trol should be turned fully clockwise (CAL.).
The DC-balance of the amplifier can be adjusted with
this control.
For this, remove the input signal and adjust the time-
base generator to its fre-running position (TRIGG.
MODE to position AUT., or STAB. fully clockwise).
Adjust the DC BAL. in such way that the line on the
screen does not move when rotating the continuous
V/cm control.