Sony PFM-42B2, Service Manual

Page: 48 / 138

2-26
PFM-42B2/42B2E
2-5. Video Processor Adjustment
YUV Level Check and Adjustment
n
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
±
5%.
(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 480/60I 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.
2-6. Watch Error Adjustment
1. Connect the jig circuit as shown in Fig. (b) and a
frequency counter to the B board CN18.
2. Enter the measurement value on a frequency counter in
the WATCH ERROR.
WATCH ERROR Jig Circuit
Fig. (b)
1
2
3
CN18
VCC
CLOCK
GND
10k
Ω
Frequency counter