Tektronix 067-0599-00 Manual page 12

Circuit Descriptions--Type 067-0599-00
3-2
Schematic
~
, Step Generator Switch and Pulse Generator
The Steps In signal to S210, the STEP GENERATOR switch, is the Step
Generator output from the 576 via the STEP GENERATOR LOADS switch of the
067-0599-00. The purpose of this switch is to provide a current load
for the current steps and a voltage divider in the voltage step mode.
Integrated circuit U230 is part of an operational amplifier whose pur-
pose is to keep the voltage change of the Steps Out constant when the
voltage of the Steps In is changed.
Q234 drives the Step Polarity Invert relay in the 576. Q234 is turned·
on and off by contact 32 of the STEP GENERATOR SWITCH, S210.
Q241 and Q251 make up a free-running multivibrator whose period is set
to 200 µs by R244. The output of the multi vibrator is applied through
R255 to the base of Q256 and amplified to produce a +25·V pulse. This
+25 V pulse is then divided by R258, R259, and R260 producing a +0.5 V
pulse. R259 allows exact adjustment of +0.5 V pulse amplitude. The
output of the multivibrator is also AC coupled via C262 to Q264 and Q268,
a ramp generator whose time constant is controlled by R268 and C270.
The ramp is output through source follower, Q271. R275 provides adjust-
ment to an exact +0.5 V sweep amplitude.
Schematic
¢,. ,
Vertical Switch
The 115 V AC line voltage is applied through the inter.,..connecting box
of the 067-0599-00 to the primary of T301, rectified, and filtered by
CR302, CR303; and C304. Q305 is a series regulator for the +25 V sup-
ply. Q308 and Q307 form a comparator circuit, using the +25 V regulated
supply.
VR310 provides a reference for the +11.7 V supply, from which a +10· V
supply is derived, adjustable by R311 and R312.
An
operational ampli...:
fier, formed by Q320, Q322, Q324, and U327, controls an error amplifier
formed by Q332, Q335, Q337, and Q340. From the emitter of Q340 an error
signal is fea' back to the gate of Q320 in the operational amplifier to
keep a constant +10 V across the resistors selected by the VERTICAL switch,
S360. Three voltages are developed from the +10 V supply through the re-
sistor divider string R314, R315, R316, and R317. These voltages, +6.25 V,
+2.5 V, and +l.25 V are applied to the VERTICAL switch and divided to pro-
vide accurate voltages for the 576's vertical sensing circuits.
Q347 and Q348 amplify the 300 ms pulses coming in from the 576.
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