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VC-483GS,GB,N
2. Observe waveform at TP401 with an oscilloscope
(with external trigger at TP404) and adjust R448
(PBY LEV) so that the requirement given in the
figure be met.
White peak voltage (DC)
Sync tip voltage (DC)
1 Vp-p
Figure 49
Figure 47
2. EE level adjustment
Note:
Leave VIDEO OUT open.
1) Select record mode.
e Playback chroma level adjustment
Precaution:
Leave VIDEO OUT open.
1. Select play mode and playback the alignment tape
(step wave).
2. Observe the output of TP401 (internal trigger) and
adjust R512 so that the burst level will be 0.275
Do not perform this adjustment except after replace-
ment of IC401
or when Carrier Set (3.8 MHz) or
Deviation (4.8 MHz) is not adjusted properly.
1) Select record mode and input color bar signal.
2) Release clipping with R210 (DARK CLIP) and R216
"i
(WHITE CLIP).
3) Connect an oscillocope to IC 401 pin 20 and read
the sync tip level (DC). Open the input.
4) Connect a regulated power and oscilloscope to
IC401
pin 20 and observe DC voltage.
5) Adjust the regulated voltage to be equal to the
100%
Figure 50
4. AFC adjustment
1) Select record mode and input color bars.
sync tip level read before.
6) Connect a frequency counter to TP203 and ad-
just R206 (for FM FREQ. ADJ) to read 3.8 MHz.
7) Raising the voltage of the regulated power sup-
ply, write down the DC voltage when the frequen-
cy counter reads 4.8 MHz.
8) Applying stepped wave (color bars) to the input,
adjust R225
(deviation ADJ) so that the white
peak voltage becomes equal to the DC voltage
obtained in 7).
25
2) Connect a digital voltmeter to TP503 and adjust
R518 to get 2.50V.
5. Adjustment of FM recording current
1) Select record mode.
2) Input color bar signal (stepped wave).
3) Observing waveform with oscilloscope (with ex-
ternal trigger at TP404), make the following ad-
justment.
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