Tektronix 502 series, Instruction Manual

Page: 58 / 114

Fig-. 6-1 1 . Grounding the junction of R15 and Cl 3.
For adjustment of the TRIG LEVEL CENT and DC TRIG
ADJ controls, the junction of R15 and Cl 3 is grounded
as shown.
the voltage when the trace first appears on the
face of the crt. Continue to rotate the STABILITY
ADJUST control clockwise until the trace bright­
ens and again note the voltage. Set the STA­
BILITY ADJUST control so that the voltage read­
ing is midway between the two voltages pre­
viously noted.
33. Upper Beam DC TRIG ADJ. Position the
TRIGGERING LEVEL control to midrange and
place a jumper from the junction of R15 and Cl 3
to ground. Place the UPPER BEAM SENSITIVITY
switch in the .5 VOLTS PER CM position and ap­
ply 100 mv of Calibrator signal to input A of the
upper beam vertical amplifier. Position the upper
beam trace under the upper horizontal center-
line. Place the TRIGGER SELECTOR switch in
the UPPER DC position and set the DC TRIG ADJ
control so that the sweep will trigger on either
the + or — positions of the TRIGGER SELECTOR
Slope switch.
Fig. 6 -1 2 . Adjustment
o f
the STABILITY ADJUST con­
trol.
The STABILITY ADJUST control is set for a meter read­
ing that is midway between the reading obtained when
the trace first appears and the reading obtained when
the trace brightens.
34. Lower Beam DC TRIG ADJ. Leave the
jumper connected as in step 33. Place the Lower
Beam Input Selector switch in the A DC position
and the LOWER BEAM SENSITIVITY switch in
the .5 VOLTS PER CM position. Connect 100 MV
of Calibrator signal to input A of the lower
beam vertical amplifier.
Place the TRIGGER
SELECTOR switch in the LOWER AC position and
position the lower trace under the lower hori­
zontal centerline. Place the TRIGGER SELECTOR
switch in the LOWER DC position and set the
DC TRIG ADJ so that the sweep triggers proper­
ly on both the + and — settings of the TRIGGER
SELECTOR Slope switch. Disconnect the jumper
and the Calibrator signal.
35. SWP LENGTH. Place the TIME/CM switch
in the 1 MILLISEC position and the TRIGGERING
LEVEL control in the RECURRENT position. Ad­
just the SWP LENGTH control for a total sweep
length of 10.5 centimeters.
©
6-8
RECALIBRATION PROCEDURE — TYPE 502