Video Processor Adjustment; Watch Error Adjustment - Sony PFM-42B1 Service Manual

3-5. Video Processor Adjustment

YUV Level Check and Adjustment
Note: Be sure to use the Z MOUNT (extension board).
1. Connect the YUV 480/60 signal to the INPUT-1
connector.
2. Select the color bar signal.
3. Measure the voltage waveform at pin-14 of IC1003 on
the B board with an oscilloscope. Confirm that
amplitude of the signal portion excluding the sync
signal is in the range of 600 mV
(If the video signal excluding sync is outside the
specifications, adjust the video signal level using the Y
GAIN.)
4. Measure the voltage waveform at pin-15 of IC1003
with an oscilloscope. Confirm that the R-Y signal has
the following amplitude.
580 mV 5 %
(If the R-Y signal is outside the specifications, adjust
the R-Y signal level using the R-Y GAIN.)
5. Measure the voltage waveform at pin-4 of IC1003 with
an oscilloscope. Confirm that the B-Y signal has the
following amplitude.
700 mV 5 %
(If the B-Y signal is outside the specifications, adjust
the B-Y signal level using the B-Y GAIN.)
Cutoff Adjustment
1. Connect the Y signal of the 525/60 signal to the Y
input only of the YUV input connector.
2. Select the gray scale signal.
3. Observe the dark area of display screen. Adjust R
CUTOFF and B CUTOFF until the dark area has
completely no color at all.
3-26

3-6. Watch Error Adjustment

1. Connect the jig circuit as shown in Fig. (b) and a
2. Enter the measurement value on a frequency counter in
WATCH ERROR Jig Circuit
5%.
frequency counter to the B board CN18.
the WATCH ERROR.
10k
1
2
3
Frequency counter
Fig. (b)
CN18
VCC
CLOCK
GND
PFM-42B1, PFM-42B1E