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(Serial Number Prefixes: 2403A-3001A)
CRT: a 0 V - 2 V Z signal proportional to the CRT writing rate, and a blanking signal
LBLANK.
Amplifier @
The Z signal, after attenuation by the front-panel INTENSITY potentiometer AlRl, drives
the input stage &g-&10. This amplifier supplies a differential current output to the Focus
Gate Amplifier and, through a Blanking Switch, to the Control Gate Amplifier.
Blanking Switch @
Control Gate Amplifier @
The input to the Control Gate amplifier is a virtual-ground, current-summing junction. Its
output voltage is given by:
Where
is the current in Q7, which is determined by the Z-axis input when LBLANK is
high. When LBLANK is low, Q7 is off, and the output of the Control Gate amplifier drops to
a few volts, blanking the CRT.
Focus Gate Amplifier @
The Focus Gate Amplifier supplies a correction voltage to the FOCUS grid of the CRT
to compensate for defocusing effects with varying intensity levels. The magnitude of this
correction voltage is set by FOCUS GAIN potentiometer R30 and the front-panel FOCUS
screwdriver adjustment AlR2. The output stage is identical to that of the Control Gate
Amplifier except for the pulse response adjustments (HF GAIN potentiometer R22 and HF
TRIM capacitor Cl0 in the Control Gate Amplifier). These components are fixed in the Focus
Gate Amplifier.
CRT Adjustments @
The CRT Adjustments set the bias voltage for the various CRT functions. Each adjustment
name is indicated on the schematic.
2 AlA
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