Tektronix 422 - Page 104

Performance Check/Calibration—Type 422 AC-DC
GEOM
i p H i k i — 11 o-Voiti
+ 12-Volt — Test Point '
Test Point
+ 95-Volt
Test Point
— 12-Volt
Test Point
R1130
12-Volts
R1125
Oscillator
frequency
Fig. 5-2. (A) Location of -12-volt and + 12-volt power supply test
points (left side of indicator), (B) location of DC power supply
adjustments (DC Power Control board).
f. CHECK—Test oscilloscope display similar to Fig.
5-3C. If necessary, readjust the test oscilloscope triggering
control so the display starts at the correct point.
g. ADJUST—Oscillator Frequency adjustment R1125
(see Fig. 5-2B) for waveform similar to that shown in Fig.
5-3C with a minimum amount of jitter.
h. Recheck step 1. If readjustment is necessary, recheck
this step also.
i. Disconnect the precision DC voltmeter and the test
oscilloscope.
3. Check DC Regulation
a. Set the variable DC power supply for +11.5-volts
output.
b. CHECK—Table 5-1 lists the power supplies in this
instrument. Check each supply with the precision DC
voltmeter for output voltage within the given range. Power
supply test points are shown in Figs. 5-2 and 5-4.
i
--------- ~ 140/isec
(C)_____________________________________________________________________
Fig. 5-3. (A) Location of external DC-input monitoring points (on
Power Mode switch), (B) location of oscillator-frequency test point
(DC Power Converter circuit board), (C) typical test oscilloscope
display indicating correct oscillator frequency.
5-10