Sony GV-A500E, Service Manual

Page: 90 / 127

5-31
9. NTSC Hi8 REC C Current Adjustment
(VC-197 board)
Set the recording levels of the REC AFM signal and REC ATF signal.
If the level is too low, the audio S/N will deteriorate, tracking will
not be stable, or SP/LP will not be discriminated properly. If too
high, color beets will be produced on the self-recording /playback
image.
Adjust the REC chroma signal recording current.
Mode VTR recording
Signal No signal
Measurement point Pin
2
of CN207 (REC RF)
Measuring instrument Oscilloscope
(20 MHz BW LIMIT: OFF)
Adjustment page F
Adjustment address 60 to 71
Specified value A = 30.3 ± 1 mVp-p (ME, E, SP mode)
Adjusting method:
1)
Set page: 0, address: 01, data: 01.
2) Insert a tape, and set to recording mode.
3) Note down the data of page: F, address: 29, set data: 01, and
press the PAUSE button of the adjusting remote commander.
4) Note down the data of page: D, address: 10, set data: 06, and
press the PAUSE button of the adjusting remote commander.
5) Set page: 2, address: 61, data: 30 and press the PAUSE button
of the adjusting remote commander.
6) Set page: 3, address: 01, data: 41 and press the PAUSE button
of the adjusting remote commander. (ME, E, SP mode)
7) Change the data of page: F, address: 69, and set the REC L
signal level (A) to the specified value.
8) Press the PAUSE button of the adjusting remote commander.
9) Read the page: F, address: 69, data (D
69
).
10) Convert D
69
to a decimal number, to obtain D
69
´.
(Refer to Table 5-1-7. Hexadecimal notation-decimal notation
calculation table.)
11) Calculate the adjustment data (decimal) from the following
equations (decimal calculation), convert it to a hexadecimal
number, and input each adjustment address.
Address: 68
D
68
´ = D
69
´
Address: 6A D
6A
´ = D
69
´ – 11
Address: 6B D
6B
´ = D
69
´ – 11
Address: 6C D
6C
´ = D
69
´ + 16
Address: 6D D
6D
´ = D
69
´ + 16
Address: 6E D
6E
´ = D
69
´ + 16
Address: 6F D
6F
´ = D
69
´ + 16
Note : After setting each data, be sure to press the PAUSE
button of the adjusting remote commander.
12) After setting data noted down at step 3) for page: F, address:
29, press the PAUSE button of the adjusting remote commander.
13) After setting data noted down at step 4) for page: D, address:
10, press the PAUSE button of the adjusting remote commander.
14) Set page: 3, address: 01, data 00 and press the PAUSE button
of adjusting remote commander.
15) Set page: 2, address: 61, data: 10 and press the PAUSE button
of the adjusting remote commander.
16) Set page: 0, address: 01, data: 00.
Note : Do not insert a plug into the AUDIO (R) terminal.
Connection:
1)
Remove C1060 (0.01
µ
F, near Pin
5
of IC101).
Note : After completing “REC L Level Adjustment” and
“REC C Current Adjustment”, replace C1060 with new
parts (1-162-970-11 CERAMIC CHIP 0.01
µ
F 10%
25V).
2) Connect Pin
^£
of IC101 and GND with a 0.01
µ
F capacitor.
0.01
µ
F capacitor: 1-101-004-00
Fig. 5-3-16.
A
0.67
µ
sec
Center of the luminace line width
Center of the luminace line width