Servo And Rf System Adjustment; Cap Fg Duty Adjustment (Vi-156 Board); Pll F & Lpf F Adjustment (Vi-156 Board) - Sony DSR-250 Service Manual

3-3.

SERVO AND RF SYSTEM ADJUSTMENT

Before perform the servo and RF system adjustments, check that
the specified value of "27 MHz Origin Oscillation Adjustment" of
"CAMERA SYSTEM ADJUSTMENT" is satisfied.
Adjusting Procedure:
1. Cap FG duty adjustment
2. PLL f & LPF f adjustment
0 0
3. Switching position adjustment
4. AGC center level
5. APC & AEQ adjustment
6. PLL f & LPF f final adjustment
0 0

1. Cap FG Duty Adjustment (VI-156 board)

Set the Cap FG signal duty cycle to 50% to establish an appropriate
capstan servo. If deviated, the uneven rotation of capstan and noise
can occur.
Measurement Point Display data of page: 3, address: 03
Measuring Instrument Adjustment remote commander
Adjustment Page C
Adjustment Address 16
Specified Value 00
Adjusting method:
Order Page Address Data
1
2 0 01 01
3 3 01 1B
4 3 02
5 3 03
6 0 01 00
7
Note: If the data is "01", adjustment has errors or the mechanism deck is
defective.
Procedure
Eject the cassette.
Set the data.
Set the data, and press PAUSE
button.
Check that the data changes in
the following order.
"1B" → "2B" → "00"
Check that the data is "00".
(Note)
Set the data.
Press EJECT button.
2. PLL f & LPF f Adjustment (VI-156 board)
0 0
Mode
Measurement Point
Measuring Instrument
Adjustment Page
Adjustment Address
Specified Value
Adjusting method:
Order Page Address Data
1 0 01
2 3 01
3 3 02
4 3 03
5 0 01
Note: If the data is other than "00", there are errors.
For the error contents, see the following table. (For the bit values,
refer to "5-4. SERVICE MODE", "4-3. 3. Bit value discrimination".)
Bit value of page: 3,
address: 03 data
bit 6 = 1
bit 3 = 1
bit 2 = 1
5-67
VTR stop
Display data of page: 3, address: 03
Adjustment remote commander
C
1F, 20, 22, 29
Bit2, bit3 and bit6 are "0"
Procedure
01 Set the data.
30 Set the data, and press PAUSE
button.
Check that the data changes to
"00".
Check that the data is "00".
(Note)
00 Set the data.
Error contents
LPF f is defective
0
PLL f final adjustment is defective
0
PLL f final adjustment time-out
0