Tektronix CSA 803C, Service Manual

Page: 46 / 280

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This circuit buffers the control signals sent to the A1 M/F Strobe Drive board
from the A5 Time Base/Controller board.
The A3 M/F Power Connector board consists of builtĆin connectors that
distribute the power supply voltages from the A4 Regulator board to the
following boards:
A1 M/F Strobe Drive board
A5 Time Base/Controller board
A26 M/F Acquisition Interconnect board
The A3 M/F Power Connect board also supplies ±15 Vpower to the A14
Input/Output (I/O) board through a 16Ćpin ribbon cable.
The regulators convert semiĆregulated voltages into stabilized lowĆripple
output voltages. The A4 Regulator board consists of the following regulators
and the voltageĆfault detect circuitry:
+50 V
-15 V
+5 V
+15 V
-50 V
See Figure 9Ć3 for a block diagram of this board.
The operational amplifiers used for the +50 V, +15 V, +5 V, -50 V, -15 V
and -5 Vregulators require that the following special voltages be generated
for their operation:
semiĆreg54 Vsupply generates the +20 Vsupply
semiĆregulated -54 Vsupply generates the -20 Vsupply
semiĆreg54 Vsupply generates the +10 Vsupply
semiĆregulated -54 Vsupply generates the -10 Vsupply
+10.0 VREF is used as a reference voltage
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This circuit consists of two window comparators and associated resistors.
The circuitry detects if any regulated supply is overĆvoltage or underĆvoltage.
The associated resistors set a hysteresis window that is 5% of the regulator
sense line voltages.
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