TB 9-6625-1979-24
(2) Adjust R230 Q300 BIAS ADJ (fig. 2) until multimeter indicates 0 25 mV dc.
(3) Adjust R150A (fig. 2) for a multimeter indication of +0.400 V (for serial number
B079000 and up), 0.037 V for serial number B076840 through B078999.
(4) Adjust R250 (fig. 2) to return oscilloscope trace to the graticule center.
(5) Adjust R230 (fig. 2) for a multimeter indication of -3.3 V.
13. Low and High Frequency Gain
a. Performance Check
(1) Connect function generator to oscilloscope Vertical 1 input.
(2) Set oscilloscope vertical scale to 200 mV and sweep time for several cycles of
display on oscilloscope.
(3) Adjust function generator frequency for 1 kHz and amplitude for exactly 3.4
major divisions of display on oscilloscope.
(4) Disconnect function generator from oscilloscope and connect TI X1 probe to
function generator and to oscilloscope Vertical 1 input, and contact ground (spring)
supplied with TI. Oscilloscope will indicate 3.4 major divisions within 0.5 minor division.
(5) Adjust function generator frequency for 10 kHz and amplitude for exactly 3.4
major divisions of display on oscilloscope. Adjust oscilloscope sweep time for several cycles
of display. If overshoot or undershoot exceeds 0.5 minor division perform b (1) below. If
aberrations exceed 0.5 minor division, perform b (2) below.
b. Adjustments
(1) Adjust R370 H.F. GAIN (fig. 2) for a square leading corner on waveform.
(2) Adjust C220 (fig. 2) for a flat top on waveform.
14. Compression
a. Performance Check
(1) Connect TI (X1 probe) between oscilloscope Vertical 1 input, function generator
and contact ground (spring) supplied with TI.
(2) Set TI INPUT COUPLING switch to AC.
(3) Set oscilloscope vertical scale to 0.2 V and sweep time to 20 s.
(4) Adjust function generator frequency for 10 kHz and amplitude for 6 divisions of
vertical display on oscilloscope. The rounding off of the leading edge of the square wave
will be 1.2 minor divisions or less.
b. Adjustments. No adjustments can be made.
15. Frequency Compensation and Risetime
a. Performance Check
(1) Connect TI (X1 probe) between pulse generator input and oscilloscope Vertical
1 input.