Tektronix 310A, Instruction Manual, Page: 42 / 132

Circuit Description-Type 310A
o f +100-Volt Error A m plifier V631 as an error signal.
Regulation o f the output voltage is controlled by +100-Volt
Series Regulator V633 in a similar manner to that described
fo r the —150-Volt Supply. Ripple regulation is provided by
divider R631-R632 between the +100-volt output of this
supply and ground. This divider applies a ripple voltage to
the screen grid o f V631 which changes the conduction o f
the +100-Volt Series Regulator in such a way as to oppose
the ripple at the output.
+300-V o lt Supply
D660A-D provides the rectified voltage fo r the +300-
V o lt Supply. The unregulated o utp ut from the +100-V o lt
Rectifier stage is connected to the negative side o f the
+300-Volt Rectifier to elevate the o utput level to +100
volts. C660 filters the rectified voltage which is connected
to the +300-Volt Series Regulator. This unregulated voltage
also provides the +400-volt unregulated o utput from the
supply. The remainder o f this circuit operates as described
fo r the +100-Volt Supply.
CRT C IR C U IT
General
The CRT Circuit provides the high voltage and control
circuits necessary fo r the operation o f the cathode-ray tube
(CRT). Fig. 3-9 shows a detailed block diagram o f the CRT
Circuit.
High-Voltage Oscillator
V704, T700 and C705 form an oscillator which operates
at a frequency o f about 25 kilohertz. The amplitude o f
oscillations in the primary o f T700 is determined by the
level at the screen grid o f V704. This level is set by the
High-Voltage Regulator stage and the operation is described
in the High-Voltage Regulator discussion. The voltage
induced into the secondary o f T700 provides the high v o lt­
age fo r the CRT.
Control-Grid and Cathode Supplies
The high-voltage transformer has four output windings.
Two o f these windings provide filam ent voltage fo r rectifier
Unblanking
— 1 5 0 V
ASTIG
CRT
CATHODE
3 -1 4
Fig. 3-9. C R T C ircu it detailed block diagram.