Tektronix 176 Instruction Manual page 31

Vertical Sensitivity
The Type 576 vertical display amplifier senses current
either through the current sensing resistors in the Type 576
or through R385 in the 176 (see the Pulsed Collector
Supply diagram). The X10 VERT button on the 176
determ ines which method of current sensing is used.
When the X 10 VERT button has not been pressed,
current from the emitter jack of the 176 device testing
jacks is conducted through P360 pins 9, 10 and 16 to the
current sensing resistors in the Type 576. The current is
then returned to the 176 through P360 pins 11, 12 and 27.
When the X10 VERT button is pressed, K150 is
energized wh ich opens the current return path from P360
pins 11, 12 and 27 through K 150·S3. Current from the
,~
Circu it Description-176
emitter jack is now conducted through R385 and back to
the charge line through K380 or K390. External inputs to
the Type 576 vertical display amplifier are connected across
R385 through P363 pins 11 and 12. K380 and K390 are
controlled by 0380 and 0390. These transistors are
controlled by the Type 576 VERTICAL switch.
The X10 VERT button, S150, controls relay K150 (see
the Mode Switching diagram). K150, 0150 and 0152
operate as a self-latching circuit. The circuit is identical to
the X10 STEPS button self·latching circuit. When the X10
VERT button is pressed and has been released, K150 will
stay energized until 0150 or 0152 has been turned off.
0150 (controlled by pins 2 and 3 of P363) is turned off
whenever the Type 576 VERTICAL switch is set below its
five highest positions. 0150 can on Iy be turned off if pin 9
of P362 is grounded.
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