Alignment Procedure; Introduction; Test Equipment Required; Preparation For Alignment - Motorola R-20010 Maintenance Manual

3. 1 INTRODUCTION
This section provides a basic (paragraph 3.2) and an
extended (paragraph 3.3) alignment procedure. The
basic procedure, which should accompany any service
work, requires only a calibrated oscilloscope. The
extended procedure, which should be performed at
nominal six-month intervals, requires the oscillo-
scope, module extenders, a calibrated digital voltme-
ter and other equipment as listed in Table 3-2. All
adjustments not covered in this procedure should be ·
performed on suitable module test fixtures only.
3.1.1 TEST EQUIPMENT REQUIRED
The basic procedure requires the test equipment
listed in Table 3-1. The additional equipment required
for the extended procedure is listed in Table 3-2.
Table 3-1. Basic Test Equipment Required
Desai ption
Model
'Oscilloscope Tektronix 2215
Test-Point Shorting Jumper
Nonmetallic Alignment Tool
• An R2001
is
a suitable substitute.
Table 3-2. Extended Test Equipment Required
Description Model
• OsciUoscope Tek 2215
'Digital Voltmeter FlukeSMOA
• RF Signal Generator
Fluke6060B
• Modulation Meter HP8901
Audio Generator HP8903
Receiver Test Cover Motorola
Extender Card Set Motorola RPX-
4379A
• An R2001 is a suitable substitute for these
separ:~te
equipments.
3.1.2 PREPARATION FOR ALIGNMENT
1.
Perform all alignments at normal ambient tem-
perature.
2. Remove the top cover of the unit to be aligned.
3. Turn on the unit to be aligned, allowing a warmup
time of 15 minutes before starting alignment.
3-1
SECTION 3.
ALIGNMENT PROCEDURE
3.2 BASIC ALIGNMENT PROCEDURE
3.2.1 LOW VOLT AGE SUPPLY
1.
Remove low voltage power supply cover and turn
on System Analyzer.
2. Connect a DVM to test point TP5 on the Output
board A5.
3. Adjust R6 on the Control board, A4, (Figure 3-1)
for a DVM reading a TP5 (A5) of +5.2 Vdc ±0.1
Vdc.
3.2.2 CRT INTENSITY BIAS
1.
Select Scope DC display and Ext Horiz input mode
on the System Analyzer. Set the Intensity control
fully counter clockwise.
CAUTION
Do not let a dot stay in one place
on the CRT screen for more than
30 seconds because it will leave a
permanent burn in the phosphor.
2. Adjust the Intensity Bias potentiometer on t he
Scope Amplifier board (Figure 3-2) until a dot
appears on the screen. You may have to use the
Vertical and Horizontal position control (Vert,
Horiz) on the front panel to bring the dot onto t he
screen. Then back off t he Intensity Bias poten-
tiometer until the dot just disappears.
3.2.3 CRT INTENSITY BALANCE
1.
Select Scope DC display and a horizontal sweep
rate of 1 mSec/Div on the System Analyzer. Set the
horizontal time base vernier to calibrate (Cal) and
adjust the Intensity control for a barely visible
horizontal line on the CRT.
2. Adjust the Intensity Balance potentiometer
(Figure 3-2) for uniform intensity of t he horizon-
tal trace from left
to
right. The Balance poten-
tiometer affects the intensity on the left side of the
trace.