TB 9-6625-781-24
NOTE
On some models, these resistors are not adjustable and no
adjustments can be made.
(3) Alternately decrease signal generator output while adjusting A19R20 or A19R7
until maximum sensitivity is obtained.
11. Ratio Input Amplifier Sensitivity
a. Performance Check
(1) Position controls as listed in (a) through (c) below:
(a) SENSITIVITY (VOLTS RMS) switch to 1.
(b) TIME BASE switch to EXT.
(c) FUNCTION switch to PERIOD AVERAGE 1.
(2) Connect multimeter to EXT TIME BASE (50V MAX) connector.
(3) Adjust A20R4 (fig. 2) until multimeter indicates 0 15 mV dc.
(4) Set OUTPUT switch (located on rear panel) to 100 CPS.
(5) Connect OUTPUT jack (rear panel) to SIGNAL INPUT AC jack.
(6) Connect signal generator output to EXT TIME BASE (50V MAX) jack, using a
50
termination.
(7) Adjust frequency of signal generator to 50 MHz and amplitude to minimum.
(8) Slowly increase signal generator output until stable indication is obtained on TI.
If signal generator output amplitude is greater than 100 mV, perform b below.
(9) Repeat (7) and (8) above at signal generator frequency of 10 MHz.
b. Adjustments
(1) Adjust signal generator amplitude output to 100 mV.
(2) Adjust A20R20 or A20R7 (fig. 2) until a stable count is obtained on TI (R).
NOTE
On some models, these resistors are not adjustable and no
adjustments can be made.
(3) Alternately decrease signal generator output while adjusting A20R20 or A20R7
until maximum sensitivity is obtained.
12. Power Supply
NOTE
Do not perform power supply checks if all other parameters are
with tolerance.