A/D Clamp Dc Level Adjustment - Sony DNW-A100 Maintenance Manual

3-8-19. A/D Clamp DC Level Adjustment

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The A/D clamp DC level adjustment is for the TBC-24
board of the board number suffix -11 or -12.
In the other suffixes, this adjustment is not necessary.
Preparing tools
. Oscilloscope: TEKTRONIX 2465B or equivalent
. Extension harness: 14P (Part No. 1-952-684-11)
. Extension board: EX-377 (Part No. J-6269-810-A)
. Alignment tape
For NTSC: CR5-1B (Part No. 8-960-096-41)
For PAL: CR5-1B PS (Part No. 8-960-096-91)
Preparation
1. Extend the TBC-24 board with an extension
board EX-377 and an extension harness.
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Before removing TBC-24 board, wait for more than 30
seconds after turning off the POWER switch.
2. Check the setting on the upper control panel.
REMOTE/LOCAL
3. Check the setting on the sub control panel.
KEY INHIBIT switch 8 OFF
4. Check that the equipment has warmed up.
Before starting the adjustment, warm up the VTR and
oscilloscope through the power for 20 minutes or more.
A B C
TP201
RV500
TP203
RV200
RV501
LOT No. S No.
A No.
RV201
E200
RV202
TP202
E501
TP500
TP601
RV503
TP602
TP604
TP606
RV502
TP603
RV601
LV601
RV604
TP605
TP303
TBC-24 Board (Side A) (Suffix-11 and-12)
DNW-A100/A50/A45
DNW-A100P/A50P/A45P
8 LOCAL (unlit 9P)
D E F G
TBC-24
RV300
RV101
TP101 TP103
RV102
E100
TP102
RV400 RV402
TP300
TP401
TP400
E302
RV303
TP403
TP404
TP402
TP301
TP406
RV404
LV401
RV401
TP302 TP405 E301
E502
Measurement / Adjustment
1. If the alignment tape is inserted, eject it.
2. Connect and set the oscilloscope as follows:
CH-1: TP202/TBC-24(C-3), 500 mV/DIV
GND: E200/TBC-24(C-1)
CH-2: TP102/TBC-24(F-2), 500 mV/DIV
GND: E100/TBC-24(E-2)
TIME: 10 us
3. Set each GND level of the oscilloscope's CH-1 and
CH-2 to the oscilloscope's scale.
4. Set the oscilloscope to CH-1 display mode.
5. Turn off the power of VTR, than wait for more than 1
minute.
6. Just after turning on the power, measure the DC level
of CH-1 (TP202) on the oscilloscope, and fill up it
measured level on the following table.
(Measurement for C)
7. Turn the oscilloscope to CH-2 display mode.
8. Turn off the power of VTR, than wait for more than 1
minute.
9. Just after turning on the power, measure the DC level
of CH-2 (TP102) on the oscilloscope, and fill up it
measured level on the following table.
(Measurement for Y)
Measurement point
CH-1: TP202/TBC-24(C-3) A = _______________
CH-2: TP102/TBC-24(F-2) B = _______________
10. Turn the oscilloscope to CH-1 display mode.
11. During play back the alignment tape in PLAY mode,
adjust the DC level of CH-1 (TP202) on the oscillo-
scope. (Adjustment for C)
PB portion: Color-bar signal (14:00 to 17:00) of
CR5-1B (NTSC) / CR5-1B PS (PAL)
1
1RV202/TBC-24(B-2)
Adj. point:
Specification: Measured DC level = A (in step 6)
2
12. Turn the oscilloscope to CH-2 display mode.
13. During play back the alignment tape in PLAY mode,
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adjust the DC level of CH-2 (TP102) on the oscillo-
scope. (Adjustment for Y)
4
PB portion: The same as step 11
1RV102/TBC-24(D-2)
Adj. point:
5
Specification: Measured DC level = B (in step 9)
14. Stop the playback of the alignment tape.
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6
It is not necessary to eject the alignment tape when
perform subsequent "3-8-20. VCO Lock-in Range
7
Adjustment".
3-8. Analog Betacam PB System Alignment
3-8-19. A/D Clamp DC Level Adjustment
Measured DC level (fill up) Note
C
Y
3-93