Add Balance Adjustment Uw; Low Frequency Response Aadjustment; High Frequency Response Adjustment; Khz Square-Wave Response Adjustment 0 - Philips PM3208 Service Manual

5.3.13
5.3.14
5.3.15
5.3.16
5 PERFORMANCE CHECK AND ADJUSTMENT PROCEDURE
ADD balance adjustment
TEST EQUIPMENT
SETTING
REQUIREMENTS
ADJUSTMENT
NO
Vertical mode - DUAL
Both channel A and B coupling - GND
Set the A and B traces at the centre of the Y-axis.
Switch vertical mode to ADD.
The trace must coincide with the X-axis of the graticule.
Adjust VR163 ("ADD" - VERT PCB) to move the trace.
Low frequency response adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT
Square-wave calibration generator
Vertical mode - A
Channel A AMPL/DIV - 5 mV
TIME/DIV - 0,2 us
Apply a 1 MHz square-wave signal to channel A and set the
amplitude at 5 div.
Adjust VR313 and VC312 ("MF" - VERT PCB) to make the line
from rising edge to 0,2 ws as flat as possible.
High frequency response adjustment
TEST EQUIPMENT
SETTING
ADJUSTMENT 1
ADJUSTMENT 2
SETTING
ADJUSTMENT
Square-wave calibration generator
Vertical mode -A
Channel A AMPL/DIV - 5 mV
TIME/DIV - 0,2 us
X MAGN - x10
Apply a 1 MHz square-wave signal to channel A and set the
amplitude at 5 div.
Adjust VR47 and VC47 ("CH1" - VERT PCB) for minimum ringing
and overshoot and the first 4 divisions as flat as possible.
Adjust VR25 and VC25 ("CH 1" - VERT PCB) for minimum ringing
and overshoot and the first 2 divisions as flat as possible.
As adjustment 1 and 2 are slightly interdependent, repeat
some times for optimum results.
Repeat for channel B.
Repeat for channel B by means of VR147-VC147 and
VR125-VC125 ("CH 2" - VERT PCB).
1 kHz square-wave response adjustment
TEST EQUIPMENT
SETTING
REQUIREMENTS
ADJUSTMENT 1
ADJUSTMENT 2
SETTING
ADJUSTMENT
Square-wave calibration generator.
Vertical mode - A
Channel A AMPL/DIV - 0,1 V for adjustment 1, at 1 V for
adjustment 2.
Apply a 1 kHz square-wave signal to channel A and set the
amplitude at 5 div.
Pulse aberrations must be < 5 %.
Adjust VC5 (VERT PCB) for minimum over- and undershoot
at AMPL/DIV - 0,1 V.
Adjust VC8 (VERT PCB) for minimum over- and undershoot
at AMPL/DIV - 1 V.
Repeat for channel B.
Repeat for channel B by means of VC105 and VC108 (VERT PCB).
5.3 PERFORMANCE CHECK AND ADJUSTMENT PROCEDURE