Philips PM3208 - 5.3.6 CRT Astigmatism Adjustment; 5.3.7 Vertical Step Balance Adjustment; 5.3.8 Vertical x5 MAG Balance Adjustment; 5.3.9 Vertical Variable Gain Balance Adjustment

§.3.6
§.3.7
5.3.8
5.3.9
5.3.10
5 PERFORMANCE CHECK AND ADJUSTMENT PROCEDURE
CRT astigmatism adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT
NO
Put FOCUS control at centre position.
Adjust VR2018 ("ASTIG" - HOR PCB) to make the spot a small
circle.
Vertical step balance adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT
SETTING
ADJUSTMENT
NO
Vertical mode -A
Channel A coupling - GND
Set MTB control for a fixed line.
Adjust VR15 ("STP" - VERT PCB) for minimum trace jump when
switching the AMPL/DIV switch.
Repeat for channel B.
Repeat for channel B by means of VR115.
Vertical x5 MAG balance adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT
SETTING
ADJUSTMENT
NO
Vertical mode - A
Channel A coupling - GND
Set MTB control for a fixed line.
Adjust VR32 ("MAG" - VERT PCB) for minimum trace jump when
pulling/pushing the variable control knob.
Repeat for channel B.
Repeat for channel B by means of VR132.
Vertical variable gain balance adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT
SETTING
ADJUSTMENT
Vertical gain
TEST EQUIPMENT
SETTING
NO
Vertical mode - A
Channel A coupling - GND
Set MTB control for a fixed line.
Adjust VR41 ("CH 1" - VERT PCB) for minimum vertical movement
when turning the variable control knob.
Repeat for channel B.
Repeat for channel B by means of VR141.
Square-wave calibration generator
Vertical mode -A
Channel A coupling - DC
Channel A AMPL/DIV - 0,1 V
Channel A variable control in CAL.
Apply
a
1
kHz
square-wave
signal
to
channel
A,
peak
to
peak
amplitude
500
mV.
5.3
PERFORMANCE
CHECK
AND
ADJUSTMENT
PROCEDURE