Tektronix 2212 Service Manual

2212 Service Manual
Power Supply
DC Outputs
The low-voltage power supply circuitry on the secondary windings ofT1350
consists of rectifier and filter components only. All the regulation is done by the
preregulator and inverter control circuitry in the primary side of this trans-
former. Both half-wave and full-wave rectifiers are used, and either simple
capacitor or capacitive-input pi-filter circuits are used. Rectifier and filter type
used for each of the secondary supplies depends on the load requirements.
Drive voltage to the fan motor is obtained from between the -5.1 V and +5.1 V
supplies. A separate pick-off on the 37V supply provides for a stable 15V sup-
ply, via voltage regulator U1390.
Separate windings on the transformer supply the cathode voltage to the crt and
the ac-drive voltage to the grid bias de restorer. High voltage multiplier U1201
uses the 2kV winding of T1350 to generate 12kV for the crt anode. An internal
half-wave rectifier diode in the multiplier produces -2kV for the crt cathode.
The -2kV supply is filtered by a low-pass filter formed by C1230, R1228, C1231,
R1229 and C1232. Neon lamp DS1200 protects against excessive voltage be-
tween the heater and crt cathode by conducting if the voltage difference exceeds
approximately 75V.
Focus voltage is also developed from the -2kV supply by a voltage divider
formed by R1240, R1246, Focus potentiometer R1247, R1245, R1244, R1243,
R1242 and R1241.
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Tektronix 2212 Specifications

General

Brand	Tektronix
Model	2212
Category	Test Equipment
Language	English