TB 9-6625-2072-24
1187/USM-281, PL-1187A/USM-281A, AND HEWLETT-PACKARD, MODEL 1821A
19. Preliminary Instructions
a. The instructions outlined in paragraphs 20 and 21 are preparatory to the calibration
process. Personnel should become familiar with Sections I, II, and V before beginning the
calibration.
b. Items of equipment used in this procedure are referenced within the text by common
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. Additional
maintenance information is contained in the manufacturer's manuals for this TI.
d. Unless otherwise specified, all controls and control settings refer to the TI.
WARNING
HIGH VOLTAGE is used or exposed during the performance of
DEATH ON CONTACT may result if
personnel fail to observe safety precautions.
REDUCE
OUTPUT(S) to minimum after each step within the
performance check where applicable.
a. Remove oscilloscope side panels.
b. Install vertical amplifier and TI into oscilloscope.
c. Connect oscilloscope to autotransformer. Connect autotransformer to a 115 V ac
source and adjust for a 115 V ac output.
d. Set oscilloscope ON-OFF switch to ON and allow at least 15 minutes for warm-up.
e. Position oscilloscope controls as listed in (1) through (4) below:
(1) HORIZONTAL DISPLAY switch to INT.
(2) AC/DC coupling switch to AC.
(3) PHASE/BANDWIDTH switch (fig. 1) to BANDWIDTH.
(4) HORIZONTAL MAGNIFIER switch to X1.
f. Position vertical amplifier controls as listed in (1) through (3) below:
(1) DISPLAY switch to A.
(2) A POLARITY switch to + UP.
(3) MAGNIFIER switch to X1.